The Food and Agriculture Organisation of the United Nations released a report on Monday called Edible Insects: Future prospects for food and feed security and since then news outlets have been looking for images of people eating bugs.

Even I was on our local TV news this week commenting on the issue. The reporter who rang to seek my input asked if I would be willing to eat a live bug for the camera. I politely declined, not just because I am a vegetarian, and not because I am squeamish. As I told the reporter and camera man, if I were to eat an animal, it would most certainly be a bug.

Indeed, I probably eat bugs all the time. As explained by an insect food producer to the ABC, most of us eat a quarter of a kilogram of insects by accident each year. Insects find their way into our foodstuffs no matter how hard we try to keep them out. Interestingly, if you eat organic, your rate of insect consumption is much higher.

So even though I have avoided eating animal flesh (including fish) for over 30 years, I nevertheless engage in entomophagy. And so do billions of people all over the world.

It is not true that the eating of insects is something that humans resort to only when they are starving. Many cultures cherish the flavours and texture of insects. Right here in Australia, indigenous people travelled to the alps each summer to feast on the bounty provided by the annual influx of bogong moths.

Which, you might say, is fine for them but not likely to convince me to fry up some moths (hint: remove the wings by scorching). So what are the arguments for entomophagy, and why on earth does the United Nations want us to do this apparently disgusting thing?

Eating insects is efficient, good for the environment, improves animal welfare and reduces the risk of diseases in humans. Let’s go through the arguments presented in the FAO report.

Efficient feed conversion. The amount of feed you need to provide to get animal based food varies greatly depending on the species. Predatory fish are expensive to raise in aquaculture because they need to be fed fish. Herbivores are more efficient, but it still takes 10 kilograms of food to produce 1 kilogram of cow, only half of which can actually be eaten. By contrast, 10 kilograms of feed will produce up to 9 kilograms of insects, of which over 95% can be eaten. If we want to find a way to produce more protein with less, insects are the way to go.

Food inputs from waste. Now let’s talk about what kind of food we give our livestock. If we have to catch fish to feed our aquaculture fish we are still dependent on wild caught protein. If we grow grain to feed our cattle, we still have to use land and fertiliser and water. But if we choose to raise insects we can feed them our waste products. Think about it, flies grow on manure. Other insects could grow on agricultural waste products high in cellulose. This transcends efficiency. Growing insects for food could actually clean up the mess made by growing other food.

Less greenhouse gases. Cattle produce so many greenhouse gases that a kilogram of beef has an impact similar to driving 250 kilometres in a car. The only insects that even produce methane as a waste product are cockroaches, termites and scarab beetles. Getting our protein from insects would significantly reduce greenhouse gas emissions.

Water savings. Agriculture consumes 70% of water worldwide, and the production of animal protein requires 100 times more water than protein from grain. This includes the water used to grow the grain to feed the animal, also known as “virtual water”. By this method of calculation, 1 kg of chicken requires 3500 litres of water and 1 kg of beef requires between 22,000 and 43,000 litres of water. Insects need far less, and can be grown throughout the drought.

Animal welfare. All of our concerns about live animal exports and battery farm hens are based on the need to reduce animal suffering. High density of livestock is necessary for commercial food production but is undesirable from an animal welfare point of view. Insects, on the other hand, are naturally gregarious. Many of them prefer to live in high densities and killing them humanely is possible and easy. No more nightmare film clips from abattoirs.

Reduced risk of disease. Think about the infections that move from animals to people and have frightened all of us: swine flu, bird flu, mad cow disease. These infections are called zoonotics, and they spread because we are similar enough to our livestock to be able to catch their diseases. Insects have a much lower risk of passing disease on to us.

In fact, it is difficult to find many disadvantages to eating insects. We don’t even have to get over our aversion to biting into a crunchy morsel with too many legs. Factories are already growing insects to produce protein powders which can be used to supplement foods we already enjoy.

The only downside I could find is that eating fresh insects collected in the wild puts you at risk of consuming pesticides. Which is one of the reasons I did not want to eat a bug for the camera – we did not have any insects from a trusted source.

The other reason is the backlash that could result from the disgust factor. Yes, it would make good TV viewing, because it is shocking and kind of gross. But if we really want people to eat more bugs (and we do!) then I don’t think we want to give the impression that we will have to start picking crickets up off the lawn and popping them in our mouths.

No, we are much more sophisticated than that. Insect protein will be produced by reputable growers who will care for their charges and ensure a high quality product. Make no mistake, this is a growth industry.

In future, entomophagy will be something we do by design, instead of by accident.

Yesterday’s announcement of the removal of trout from a small creek in the Alpine National Park to protect a critically endangered native fish highlights the problem that is trout.

Trout have been so successfully and so pervasively introduced into Australian freshwater systems that most people now think that they are native. The truth is that trout have caused the extinction or demise of many freshwater fish and invertebrate species, including some excellent angling fish such as the Murray cod, Macquarie perch and trout cod.

The introduction of trout to Australia was supported by Acclimatisation Societies which supervised the hatching and release of introduced trout without any consideration of its impact on native fauna.

This does not surprise us because we know that these organisations deliberately introduced thistles, sparrows and rabbits, all of which are well known pests in an Australian context.

The surprising thing is that trout have evaded the pest label, and despite abundant evidence that they are causing the extinction of native fauna, their continued existence in Australian rivers is supported by government agencies that release millions of trout fry every year.

These same agencies are responsible for protecting the native species impacted by trout, and ironically breed and release trout’s victims at the same time. In 2012, Victorian Fisheries hatched and released Murray cod, golden perch, trout cod, silver perch, Australian bass and Macquarie perch, all of which are native fish struggling to compete with trout. At the same time they released brown trout and rainbow trout despite the fact that many trout populations are known to be self – sustaining (in other words, not at risk of extinction). To be fair, Victorian Fisheries now only releases troutinto lakes or impoundments, but the movement of these populations into nearby rivers is virtually guaranteed.

Trout have been removed from other small rivers and creeks in the past to protect the barred galaxias and the spotted tree frog. The responsible agencies are aware that trout are a serious threatening process, and yet they are unlikely to ever remove trout from a large river. This is because recreational fishers have come to believe that trout fishing is something which every Australian has a right to. Worse, many fishers think this is because trout are a natural part of the Australian environment and therefore deserving of our protection.

Obviously, trout fishing is an important part of the tourism industry and many rivers are so well stocked with trout that there is no point in trying to remove them. On the other hand, few Australians realise that we enjoy trout fishing at the cost of excellent native angling experiences.

Macquarie perch and trout cod (formerly known as blue-nose cod in Victoria) were excellent angling species before they became endangered. Murray cod are still highly prized where populations are not too vulnerable to be fished, but they no longer grow to the great sizes of the past.

People who fished the Murray River used to be called “whalers” because they came back with monster fish as large as themselves. Current regulations require anglers to throw fish back if they are above a certain size, so the thrill of fishing for something that could be larger than yourself is no longer available.

This is not due to trout alone, of course. River regulation, pollution and habitat alteration all play a role in declines of our native fish. But the reverence with which trout are held among fishers obviously plays a role.

The construction of a barrier to prevent trout from moving into a small stream and the removal of 700 trout by electro-fishing is an important and laudable step towards the protection of one species of upland native Australian fish. The Shaw galaxias is a critically endangered species that would not have survived without this intervention.

But let it also remind us that trout are threatening native fish in rivers, impoundments and lakes, and too few people are concerned because they think that trout belong here.

Unfortunately, trout are actually worse than rabbits, because they are both carnivorous and voracious. As a fisher said in 1905 in the Sydney Morning Herald: “Trout will eat anything but the log fences hereabout. They have cleared out the bream, the cod and the carp, but we will not mind that if they stay themselves.”

Some of us do mind.

Last week, Victorian Fisheries announced changes to the fishing regulations for Murray Spiny Freshwater Crayfish to bring them in line with recent changes in New South Wales.

This is a quick turnaround, but will not be considered quick enough by fishers who have already made plans for the 1 May season opening. It was necessary because NSW fishers, whose season has been moved from 1 May to 1 June, were quite likely to shift their fishing trip to Victorian waters, thereby putting extra pressure on crayfish in some populations.

I have already written about how I felt about the new rules in NSW, which will go a long way toward addressing some of my concerns about the viability of this fishery. What I haven’t said before is how remarkable it is that these animals are part of a fishery at all.

In Victoria, the Murray Spiny Crayfish are on the threatened list of the Flora and Fauna Guarantee Act.

This means that when I want to collect this species, in addition to the usual research permits from Victorian Fisheries and my University’s ethics department, I need to get permission from the Department of Sustainability and Environment to handle this threatened species. That it is harvested and eaten by people for three months of the year on a humble fishing license is a highly unusual situation.

Obviously, many fishers believe this should continue and see their yearly crayfish trips as a right, rather than a privilege. In some cases, they are fishing in areas where the decline in numbers is not apparent, so they may wonder why these changes in regulations are necessary.

One of the new regulations is the introduction of a maximum size, which will mean that really big animals cannot be removed from the river. The reason this is necessary is that fishing pressure tends to remove all large males, which reduced the productivity of large females.

Basically, a large Murray cray female will not produce as many eggs when she mates with a smaller male. This can have a big impact on a population because the largest females are the most prolific breeders, producing up to a thousand young in a season under the right conditions. When they are forced to mate with a small male, their egg set will be much smaller, and the next generation is less secure.

Under the new regulations, it is hoped that some males are lucky enough to escape the pot until they exceed the maximum size limit, at which point they can live the rest of their long lives servicing those large females and keeping the population strong.

So even though, according to NSW Fisheries, recreational fishing does not appear to be the main cause of the decline of Murray crays, managing fishing pressure is the best way to ensure the species recovers from its current decline. Protecting habitat is another important component, but given that this would mean, in some cases, preventing drought, it may be beyond our ability to manage.

Just to be clear, the Victorian rules for Murray crayfish season now reflect those of NSW: a minimum size of 10 cm OCL (occipital carapace length: from the eye to the base of the tail), a maximum size of 12 cm OCL, reduced bag limits (to 2 ), reduced possession limits (to 4) and a delayed season opening to 1 June.

In my own discussions with fishers, many are motivated (as are my students) by the joy of meeting these remarkable creatures, and eating their catch is not as important as being able to introduce these animals to their children. A catch and release fishery would meet their needs, but ensuring compliance would be a significant challenge.

Our research at present is focussed on a river that is not part of a commercial fishery. We are examining the impact of various land uses (cropping, pine plantations, cattle) on the distribution of crays. We are also interested in the temnocephalan worms that use the crays as a substrate: these unique flatworms are not parasites, but rather partners in crime; the crayfish are their godfathers. By assessing the distribution of temnocephalans along a gradient, we hope to learn more about their ecology, which is linked to but not completely driven by crayfish abundance.

My two new Honours students have just begun their fieldwork and it has been a joy to watch them fall in love with these spiny, gorgeous, often grumpy creatures. I can therefore understand the pain that fishers feel when their fishing activities are curtailed. Just remember that the future of this species may depend on us leaving them alone in some areas.

Fisheries NSW have recently announced large changes to the rules about fishing for Murray crayfish after calling for the status of this species to be changed. The Murray crayfish is now considered vulnerable in New South Wales.

Fishing for Murray crayfish will continue, but only in certain rivers, with a shorter season, lower bag limits, and increased minimum sizes. All of these changes are in line with the recommendation made by myself and others following our research on the Murray crayfish.

The fishing season would normally begin in a few short weeks on 1 May, but now this will be delayed until 1 June. Some fishers have expressed their dismay at the timing of announcement, because they have already made plans for trips in May. I can understand their frustration, but this shift in timing will save hundreds of female crayfish.

The fishing season for Murray crayfish was designed to coincide with their breeding season. This is the time when females carry eggs under their tail (we say they are “in berry”). Our research showed that many large females had not yet laid their eggs in May. The rule is that berried females must be returned to the water, which protects breeding females and their offspring from fishing pressure. We were concerned that with a delay in breeding season, these animals could be caught and eaten early in the season, a week or two before they produced the next generation. By shortening the season by one month, Fisheries ensures that all breeding females will be protected.

Another major change is the increase in minimum size from 9 cm to 10 cm OCL (occipital carapace length), which is the distance from their eyes to the beginning of their tail. This will also protect the species by ensuring that all crayfish get a chance to achieve sexual maturity and mate before they end up in a fisher’s pot. The downside is that it will be that much more difficult to find legal sized animals in some areas. Where the fishing pressure has been strong, legal sized individuals have been rare.

The reduced bag limits (from 5 to 2) will also mean that fishers may have to pack other food if they want a good feed during their fishing trip. In the short term, this will reduce the pressure on crayfish populations and I hope that this means they can bounce back.

The maximum size of 12 cm OCL will give large crayfish a get out of the net free card. Large crayfish produce significantly more young, and a few experienced breeders surviving in each stretch of river can vastly improve the viability of that population.

The challenge is to get the word out to the recreational fishing community, so that this year’s fishers are able to comply with these new rules. The rules are there to protect the fishery for the future.

One question remains: will Victorian Fisheries change their regulations to match? If so, then the Murray crayfish has a much brighter future.

I welcome yesterday’s announcement that the Victorian government will continue to contribute to the Murray Darling Basin Authority. Recent cuts by the New South Wales and South Australian governments have already had an impact on research capacity in the region.

The future of the environment in the Murray Darling Basin will be at risk if it is driven by politics alone. We need evidence and sound scientific analysis to ensure that the decisions we are making are responsive to the needs of society and the environment.

It is hard to follow the logic of water policy in Australia, because each pile of money is announced as if it is a separate, stand alone project. In 2008 the Water for the Future program was set up with $12 billion to reduce water use with the goal of recovering environmental water. More recently, $1.77 billion was set aside to recover additional environmental water, while The Living Murray program has invested $287.9 million to deliver and manage environmental water delivery to five of the six Living Murray icon sites.

When funds were cut to the Murray Darling Basin Authority, what was at risk is the ability to oversee these various projects and how they interact, and the capacity to do research on the ongoing health and sustainability of the basin.

The Murray Darling Freshwater Research Centre (MDFRC) is based on La Trobe University campuses in Wodonga and Mildura. My own department works closely with the researchers in the centre: co-supervising PhD and Honours students, providing advice to water managers, contributing to outreach programs for young people, and monitoring the success of water releases and other government initiatives.

The MDFRC has provided expert scientific advice to water managers for 25 years, and the staff have become adept at responding to queries for research on the impact of drought, salinity, algal blooms, acidic soils and blackwater events. When they are not reacting to environmental crises, they are quietly amassing data that has the best chance of informing Australians about how to manage the precious water resources in the Murray Darling Basin.

Recent cuts have put the Murray Darling Research Centre at risk. They may soon lose up to 80% of their capacity. By capacity we mean staff, many of whom have extensive expert knowledge of the basin. These long term researchers know how to get the river research done, which is not just another government desk job. From running electrophoresis boats to predicting the state of muddy roads to being able to identify thousands of freshwater species, the expertise and knowledge required would take years to replace.

It is ironic that opposition to the Murray Darling Basin plan has made it harder to do research on the Murray Darling Basin. At a time when detailed analyses of the options are critical, and when the benefits of a healthy river are more apparent than ever before, disagreements about the role and future of the Murray Darling Basin Authority (MDBA) have limited our research capacity. Yes, there have been job losses in the recent past, and the MDFRC is bracing itself for more to come.

And yet these people give us the best chance of spending the billions of dollars committed to environmental works wisely. For some reason it is easy to find money to spend on infrastructure, but hard to find money to pay the salaries of people who can tell us the impact of that spending. In years to come, Australians will want to know the payoff from our investments in environmental water management, but we are at risk of cutting the funding that supports the monitoring that will allow us to answer those questions.

Some people think that environmental water will be taken from the river at the cost of communities that depend on the river. This makes no sense to me. Environmental water ensures the future of the river, and hence the communities that rely on it.

The researchers whose jobs are at risk are not statistics to me. They are my colleagues, people with families who live along the Murray River and love it. They are also farmers and fishers and friends. The communities they live in will be harmed in several ways if the MDFRC does not continue. Job losses always have an impact in regional communities, but these will also harm the delivery of knowledge to those communities and put them at further risk of unsustainable practices at all levels of government. Catchment Management Authorities, Landcare Groups and fisheries organisations rely on the MDFRC to answer important questions and provide sensible advice.

The MDFRC is a joint venture between the Murray Darling Basin Authority (MDBA), La Trobe University and CSIRO, with additional funding from the Federal Department of Sustainability, Environment, Water, Populations and Communities, or SEWPaC.

Continued funding of this centre is critical. Thanks to Peter Walsh, the Victorian Water Minister for not cutting his state’s contribution to the MDBA. Please lobby your politicians in other states and federally to follow his lead.

Last week a group of Japanese scientists published a paper describing a sea slug with a disposable penis.

As strange as this sounds to us, the concept of the detachable penis is not a surprise to malacologists, which is what we call people who study slugs, snails, octopus and other soft creatures.

Actually, I was thinking about snail sex a couple of weeks ago because our department ran a taxonomic workshop where, among other expert presentations, a malacologist named Winston Ponder told us how to tell one gastropod from another. I learned for the first time that many snails have an external cephalic penis.

Think about what that means. A cephalic penis doesn’t have a head, it grows out of your head. The snail penis looks like a fleshy dreadlock growing right near their stalked and googly eyes. At least they can see what they are doing when the deed is being done.

And suddenly I realised that snails have to carry their penis on their head, because if it were tucked inside their shell, how would they use it? I wondered why I hadn’t thought of this before, while Winston enlightened us about other anatomical oddities of our molluscan brothers.

You might think that two days of this kind of thing would send a roomful of human beings into a paroxysm of giggles, but taxonomists are made of stern stuff. That fact is that people who name and describe species spend a lot of their time illustrating and discussing the shape of sexual organs. (Unless you work on fish or birds, but that’s another story.)

The sexual organs are often the most distinctive feature of a species. We often know plants by their flowers. While you may recognise a rose bush from its foliage alone, you cannot be sure of the exact type of rose you until the flowers come out. For some reason, you are not ashamed to pluck that sexual organ and stick your nose in it. So don’t judge scientists for mounting snail pricks on slides, and categorising them.

Gastropod penises come in different forms, including the bilobed, or two-pronged version. Some snails have internal penises, and others are aphallate. That is a word that means “without penis”. These would be the dick-less snails. One might be tempted to call them girls, except that they all really are, even the ones with penises. This is because snails and slugs are hermaphrodites, with both girl and boy reproductive parts, completely functional, and often in multiples.

I wanted to ask Winston Ponder about if the aphallate species were considered “lower” gastropods because as humans we believe that anything without a penis cannot be highly evolved. I never got around to it, but my head was unaccountably full of questions about sex in snails, which may be why the latest news about slug sex caught my attention.

Slugs are snails that have lost their shells, and this has allowed them to put their penis back where it belongs, which to say away from their head. When slugs have sex, they line up head to toe because their male and female bits are always on the same side of their body. The logistics of two penises and two vaginas creates a complex set of sexual politics, including something quite sinister in land slugs, called apophallation.

The Greek prefix a- means without, and phallate means to have a penis, so it makes sense that aphallate snails have no penises. The Greed prefix apo- means separation, so apophallate slugs had a penis at one point but lost it somehow. This seems particularly tragic in the case of the well-endowed banana slug, whose scientific name means “big penis”. The truth is that apophallate is a fancy word for a violent act.

Sometimes land slugs get stuck during the sexual act. When they cannot separate after sex, according to Wikipedia, “one slug gnaws off either its own, or its partner’s penis”.

I find this hard to believe.

Even a slug is going to hesitate about gnawing off its own penis when it could bite off another slug’s penis instead. The alternative is a level of altruism that I cannot believe: slugs in love protecting their partner by making the ultimate sacrifice. I prefer to believe this quote from an actual malacologist who has considered the pay off involved:

“The apophallated slug … cannot regrow his penis and is now obligated to be a female and forced to offer eggs. It may be that the castrator can raise his reproductive success by increasing locally the density of females.”

This brings up the idea that although slugs start out with the equipment to be male or female, they can be forced to take the role of the female. Growing and nurturing eggs is an energetic burden, and if the decision of who gets to be the male happens during the sexual act, then we have a true battle of the sexes.

Some flatworms “penis fence”, which means that they fight off their partner’s penis while trying to make contact with their own. The first to penetrate remains male, while the other has to carry and care for their developing eggs. The Australian species that does this is not only two-faced, it has two penises and two-tailed sperm.

Which brings us to the sea slug with the disposable penis. Chromodoris reticulata is a sea slug only a few centimetres long, and when the scientists brought specimens into the lab for observation, they were not surprised by the sight of two penises reciprocally inserted, but by the fact that their penises fell off about 20 minutes after the sexual act.

By offering these individuals mating partners at various intervals, they learned that it took about 24 hours for these slugs to regrow their penises. One individual was able to mate three times in three days, regrowing his (or her?) appendage each time.

The most famous detached appendage is the hectocotylus, or octopus penis, first described by Aristotle. Because it remained inside the female, it was long thought to be a parasitic worm.

Argonaut octopus males are so small compared to the females that scientists did not realise they were the same species for hundreds of years. They use their modified arm to transfer the sperm to the female, but it breaks off and they never get it back. As a consequence they mate only once in their lifetime.

Athough losing your penis is not unusual among molluscs, growing it back again is a neat trick.

Everyone knows what a yabby is, don’t they? Well, you would be surprised. Those charming little critters with nippers in your local dam may belong to the species Cherax destructor, also known as the common yabby, but they may also be juvenile spiny crayfish (genus Euastacus), adult burrowing crayfish (genus Engaeus) or another species within the genus Cherax, including gilgies, marron and redclaw.

As a scientist who has worked on Australian freshwater crayfish for decades, the diversity of common names in this group is one of the most frustrating part of the job. It is not that I mind people using the vernacular or that I refuse to use it myself, it is just frustrating to be labelled an idiot by well meaning locals.

Here is a typical scenario: I am poking around in a creek in some remote location, with my laminated scientific collecting permit tucked into the field kit, and a farmer or fisher or curious teenager asks me what I am doing. The answer is simple, I am trying to collect the rare and beautiful species (insert scientific name here) for the purposes of research.

But how do I explain it to someone who thinks that species is a yabby, craybob, lobster or gilgie? If I use the scientific name I sound like a wanker, and if I use the word yabby I will be lying (becuase I almost never go in search of Cherax destructor). Invariably, whatever word I use I will stand corrected by the local, who has lived their whole life calling that species (insert “common” name here). And at that point I lose credibility. Doubt and suspicion floods their eyes. How can I be a crayfish expert if I do not even know the “correct” name for their local crayfish?

My own humiliation is only the tip of the iceberg. Because many species of freshwater crayfish have limited distributions and are therefore rare and threatened, it is dangerous when the locals consider them to be “common”. It is even more dangerous if they think they are yabbies, because the fishing regulations for yabbies are quite generous (you can kill and eat 200 per day).

On the other hand, any species in the genus Euastacus (also known as spiny crayfish, which includes the mighty Murray cray) are protected from fishing if they are under a certain size. People who assume that all small crayfish are yabbies may be scooping up endangered species to use for bait. It happens all too often and is one of the threatening processes for the group. Extinction by obscurity. The assumption that an unknown crayfish is “just a yabby” is dangerous for the crayfish.

The surprising and important fact that most Australians do not know is that there are almost 140 species of freshwater crayfish in Australia, in 10 genera.

The genus Cherax includes the yabbies, gilgies, marron and redclaw, but also a couple of dozen other species that have no common name at all. The genus Euastacus are usually known as crays (but so are marine lobsters in Adelaide, and that is another group entirely) and there are currently 50 different species.

Burrowing crayfish live underground most of the time, and they belong to the genus Engaeus if found in Victoria aor Tasmania, the genus Engaewa in Western Australia, or the genus Tenuibranchiuris near Brisbane.

Two additional genera are found only in Western Victoria, and three more in Tasmania, one of which (Astacopsis) is the largest freshwater crayfish in the world. All of them are special, and none of them can be described using their common names.

One species of Astacopsis is also known as the Giant Freshwater Lobster, a great common name that confuses me by using a word for a freshwater creature that is normally used only for animals found in the ocean. I guess Tasmanians don’t like to follow the rules.

The point I am trying to make is that if you are lucky enough to have a creek or river or swamp near you that is full of creatures that look like yabbies, take a moment to consider the possibility that they may instead be the critically endangered Euastacus robertsi (which are purple underneath) or the critically endangered Cherax leckii (which looks just like a yabby). In some locations, such as Fitzroy Falls, you can catch yabbies in the same net as a critically endangered Euastacus. It is your responsibility to learn how to tell them apart.

Most people do not plan to do any harm to these beautiful and amazing creatures, but most people do not think they are doing any harm when they set out to have a feed of yabbies. Just bear in mind that not all crayfish are yabbies.

Some of them are rare and beautiful and have no common names at all.

If you had to guess what creature in the world had the largest testes, I doubt you would guess that the prize belonged to a cricket.

The testes of the tuberous bush cricket (Platycleis affinis) are an internal affair, taking up most of the cricket’s abdomen. At nearly 14% of their body weight, they are disproportionately large when compared to other species. Just think, a 100kg human would be walking around with 14kg of testicles, which would be mighty uncomfortable.

Why do these crickets need all that sperm power? It is because their females are highly promiscuous. The male bush crickets do not release more sperm than normal in any given sexual act, but they can be called upon to do it so often they apparently need the reserves. In the world of insects, it is not worth missing an opportunity, and if the females are going to be all available like that, then a cricket needs some world-class balls.

But this is not the only sexual record held by crickets. An Australian species known as scaly crickets (Ornebius aperta) have the most frequent sex of any species in the world. These little guys can do it more than 50 times in a few hours, often with the same female!

Why do they have to keep this up? Because she eats it.

That’s right, cricket sex provides more than the spark for the next generation. Males actually produce a package called a spermatophore, which is sperm wrapped up in a nutritious protein package. When the males insert it into a special opening in the females, sometimes she just bends down to gobble up her yummy post-coital snack.

Australian spiny cricket males respond to this sabotage by releasing only a few sperm per package, between 5 and 225 sperm per copulation, an astonishingly low amount compared to the average (100,000). Yet when researchers measured sperm loads in females, they had up to 20,000 sperm stored away. This means that they had sex up to 200 times to collect that amount.

Of course the females were storing up more than sperm. They also gathered nutrients that will help them develop eggs for the next generation. Other species of crickets manage the situation by offering a courtship gift in the form of food from the dorsal glands that distract the female and give her something to eat during sex.

Some female crickets seek out males in order to get these tasty gifts. A study of 32 different species of bushcrickets showed that the larger the spermatophore, the more likely the females were to actively seek out males. These gifts are costly to produce, so species that produce small spermatophores may mate twice a night, while those with large spermatophores may mate only once or twice in a lifetime.

The final cricket sex record goes to the Mormon cricket, which produces a spermatophore that is 27% of its body weight. That’s a huge investment in wild oats, which is a good description, since most of the package is food. The Mormon crickets are flightless and form swarms similar to locusts. These great walking hordes are often so hungry that cannibalism is common.

Female Mormon crickets will compete for males just so they can get a feed, and the benefit for the male is that some of his sperm may make it to the next generation.

Crickets are not likely to be overly loyal to each other, because research on Spanish field crickets shows that individuals with more mating partners leave more offspring. This applies to both male and female crickets, so it is surprising that males will nevertheless protect a female that they have mated with.

Male crickets will linger near a female they have recently given their sperm to, not to scare away other suitors, but to protect the female from predators. He does this at his own peril, because males that hang about after sex are four times more likely to be eaten. On the other hand, the females are six times less likely to be eaten if he is there to protect her.

Male crickets are not confused about the goal of spermatophore transfer. But female crickets want more than just sperm from their partner. A meal (or several dozen meals) increases the male cricket’s chance of getting lucky.

Maybe they are not so different from people, after all.

Murray crayfish never fail to impress. When you pull up the hoop nets from the murky depths and those large white claws start waving about, the uninitiated invariably recoil, sometimes even threatening to upset the boat in their efforts to avoid these spiny armoured angry aliens.

Probably this is why fishers enjoy catching them so much. The pay- off is a sense of being part of something strange and magical. There is a thrill involved in grabbing one of these beasts while the claws wave and snap and the tail flips water in your face. There is the joy of discovery and secret knowledge when you turn it over to check for the berries that mean it is a fertile female.

If you have not seen a Murray cray live, feel free to have a look at me and my ten-legged friends as shown on Catalyst last year.

In the past, a long weekend could be self-catered by the catch, a pot of lovely lobster meat after a day on the river. Nowadays, fishers are struggling to fill the modest bag limit of 5 per day. Legal sized individuals are increasingly hard to find, and the really large animals that could feed a family and provide bragging rights for the rest of the season are just not seen anymore.

Murray crays used to be abundant enough to support a commercial fishery. Now they are protected in South Australia, where they are as rare as a mythical beast. They are protected in the ACT, where they can be found but are listed as vulnerable. They can no longer be found near Mildura, where they used to support a recreational fishery. And they are threatened in Victoria and part of an endangered lower Murray ecological community in NSW, but are still part of a recreational fishery in those states.

Naturally, there are restrictions. Murray cray season is closed from the beginning of September to the end of April. Berried females (those bearing eggs that will produce the next generation) must be returned to the river, and the bag limit is 5 crays per person per day. But in many popular fishing spots it is getting hard to find legal sized individuals, and fishers are naturally tempted to take animals that are nearly legal so that their day on the river is not wasted.

These declines are not new. In Victoria the fishery was closed in 1983 in response to low catch rates, but it was reopened again in 1991 with a range of restrictions, including the minimum size limit of 9 cm OCL (occipital-carapace length, or the distance between the eyes and the base of the tail).

Our research on the Murray crays in the Ovens River compared catch rates over many years with a survey in the 2010 season. This included contacting and seeking comments from people who fish for Murray crays. We found an alarming decrease in the number of animals in the river as measured by number caught per net lift (or catch per unit effort). Perhaps more concerning was that the 91 fishers who responded to our survey agreed that the catch rate had decreased, the animals were smaller, and it was increasingly difficult to reach their bag limit.

More poignantly, some of these fishers rang us to express their dismay that they were still allowed to do this. Some reported that they had voluntarily stopped fishing and hung up their nets. Now they have a chance to report directly to the people who control the regulations.

The Fisheries Scientific Committee of the Department of Primary Industries in NSW is seeking public submissions on a proposal to list the Murray cray as vulnerable. This will not lead to an immediate closure of the fishery, but it will protect their habitat. Submissions are due next week on 21 December.

Fishing pressure did not wipe out the crayfish in South Australia, a change in the river’s conditions that did that. River regulation, droughts and even floods have impacted Murray crayfish populations. So fishing pressure is not the only cause of decline, but it is one of the few contributing factors under our control.

Low oxygen conditions caused by floods last year meant that Murray crays were walking right out of the river, which got everyone’s attention. I went on local TV to tell people not to gather them up for a feed, because some folk made the assumption that the crays were dying. Unlike fish, crayfish have gills that can function out of the water as long as they remain damp. These crays were catching their breath and could return to the river as long as they were not attacked. The truth was that birds and other predators probably had more of an impact than people. Everything, it seems, likes to eat crayfish.

I will be putting in a submission about the Murray cray and urge others who have appropriate local knowledge to do the same. Use this link to make your views known about this iconic and apparently delicious species. I say apparently, because I have never eaten one myself.

For me, it would be like eating a unicorn.

Someone who recently discovered that I do research on freshwater crayfish asked a simple question: How long do yabbies live? But this simple question has no simple answer. I found myself opening and closing my mouth as I tried to figure out where to start, and realised I looked like a complete idiot.

Why is this such a hard question to answer?

Well, it depends on a bunch of stuff. It depends on the yabby, for starters. What species of yabby does the questioner have in mind? It depends on the habitat. Is the yabby in a dam, a river, underground in a burrow or in a fish tank in your bedroom? It depends on the environment and the weather. Is there a drought or a recent flood? Has a bushfire filled the river with ash?

And it depends on the luck of the yabby. Most yabbies die young, because they are on everyone’s menu. If they are not eaten by a fish or a bird or another yabby, they are likely to end up on your plate.

Indeed, when I put “yabby definition” into my search engine to find out what other people mean when they say the word yabby, I got the following: “A small freshwater crustacean with a sweet, delicate flesh. Yabbies can be substituted with shrimp or crawfish.” In other words, when most people think of yabbies, they are thinking of food.

To me, however, yabbies are members of the genus Cherax, a group of freshwater crayfish found almost exclusively in Australia. More specifically, it usually refers to the species Cherax destructor, which is also known as the common yabby.

Last week, in the state of Victoria, the government changed the rules about catching yabbies. They have set the bag limit to 200 individual yabbies per day, which is in line with the rules in New South Wales and South Australia. Previously, the limit was 30 litres, and the problem was that if people were chasing juvenile yabbies for the purpose of selling them as bait, they could collect literally thousands of yabbies every day. If kept up for an extended period, this fishing practice could destroy entire populations.

Another change to the yabby rules is that berried females must now be returned to the water. A female in berry is carrying eggs under her tail, so that killing her would result in the unnecessary death of hundreds of unhatched yabbies. All other freshwater crayfish are protected in this way, and it is common sense to provide this minimum protection, even for a species known as C. destructor.

The final change provides a little relief for the yabby hunter: a new type of net has been approved for catching yabbies. The old opera house net is banned in public waters in Victoria and eastern New South Wales because of the risk of catching platypus, water rats and turtles, who will drown if caught in these nets. The new open-top pyramid nets allow the fisher to set a trap that will hold a reasonable haul of yabbies, while allowing protected air-breathing species to escape.

There are well over a hundred species of freshwater crayfish throughout Australia, and some people call them all yabbies. Most people can recognise the really tasty versions: marron, red claw and crays, but all of these are hard to tell apart when they are still small. Unfortunately, people sometimes use juvenile Murray crays as bait because they assume that any small crayfish are yabbies. Being able to tell the species apart would really help with their conservation.

There are 38 species of freshwater crayfish in Victoria, of which 27 species are threatened. Freshwater crayfish are critical components of ecosystems where they are found: as juveniles they are tasty snacks for other species, and as adults they are top predators critical to managing the food web. Crayfish are environmental engineers — they dig burrows, chew on submerged logs and rearrange aquatic vegetation, all to the benefit of other freshwater species. If the crayfish are removed from the system, our freshwater systems will suffer.

So how long can a yabby live? In a farm dam, with a good source of food and a bit of luck, they could live for ten years, although five years would be more common. But if the lake they are living in dries up due to drought, then the yabbies burrow down into the mud and aestivate (or hibernate), waiting for the next heavy rains. It is anyone’s guess as to how long they can stay down there.

Lakes that have been completely dry for many years become full of large yabbies within days of filling up with water. Those animals come out in such vast numbers, that these populations are enthusiastically targeted by fishers keen to harvest the bounty. Last year, a flood produced so many yabbies that the locals were scooping them up with shovels.

The problem is that these adults are a remnant population; their job is to feed and breed in order to produce the next generation of crayfish. When the droughts are long, and the fishing pressure is heavy, we risk removing the breeding stock and reducing the overall size of yabbies.

A bumper year is predicted for yabby harvests throughout south eastern Australia. This is a good time to remind ourselves that even the hardy, virtually indestructible species C. destructor needs to be protected from unrestrained fishing pressure.

How long can a yabby species survive? This is a hard question to answer, but the common yabby will remain common a lot longer under the altered fishing rules in Victoria.

People who live far from the seashore still benefit from ecosystem services delivered by the oceans of our planet, and people who cannot see the sea still damage the oceans by impacting the water quality of rivers that flow to the sea.

A recent study by Glenn De’ath and colleagues has analysed the causes of the decline of coral in the Great Barrier Reef, and found that a large proportion of coral mortality is due to algal blooms that are caused by increased nutrient loads delivered by freshwater rivers and streams. This means that managing the health of the reef means convincing people who live on the land to take part.

What does the ocean do for you?

Some people believe that if they do not live on the coast, or spend time fishing, then conserving oceanic habitats or species has no benefits for them personally. But the oceans provide climate regulation by absorbing carbon dioxide, it produces oxygen for us to breathe, and seafood provides essential protein for a large proportion of people on our planet. These are things we will not miss until they are gone. We call them ecosystem services, and they are easy to take for granted.

A recent analysis by the Centre for Policy Development concludes that Australia’s marine estate provides over $25 billion worth of ecosystem services every year. That figure does not include the money produced from commercial fishing, boat building, marine tourism or offshore oil. The marine reserve network, which is widely undervalued, provides $2 billion of ecosystem services each year.

But putting aside areas of marine habitat is only one aspect of ensuring the health of our oceans. Much more needs to be done to protect ourselves from catastrophic consequences. And the Great Barrier Reef is only one component of our marine estate, but it is both visible and important, so recent research on the causes of decline in live coral is instructive.

Study of coral reef deaths

Based on 2,258 surveys from 214 reefs over 27 years, a study by Dr De’ath et al. quantified the mortality of coral across space and time within the Great Barrier Reef (GBR). They found a large decline in live coral across the GBR over this period, from 28% coverage in 1985 to only 13.8% coverage in 2012. But the damage is not evenly spread across the GBR: in the isolated north the impact is far less than in the developed southern end, where live coral coverage has fallen as low as 8.2%.

More interestingly, the researchers identified three causes of coral death: 1) bleaching, 2) tropical storms, and 3) crown of thorns starfish. At first glance it would appear that these are beyond human control, but on careful examination, all three may be linked to human activities.

Bleaching occurs when symbiotic algae that capture energy from the sun for their coral hosts are affected, causing the death of the coral itself. Bleaching is triggered by warm water events, which are increasing due to global warming. Tropical storms will always be with us, but the kinds of damaging cyclones that cause damage to reefs are also likely to increase in frequency with warming ocean temperatures. To manage either of these causes of coral death we need a global response to reduce greenhouse gases. In the past three decades, tropical storms and bleaching were responsible for about 58% of coral deaths in the Great Barrier Reef.

The third cause of coral decline is a starfish that can become super abundant. The crown of thorns starfish are voracious predators of coral, and 42% of coral mortality was caused by outbreaks of this single species. One way to reduce crown of thorns outbreaks is to ensure that their predators remain prevalent, and restrictions on fishing have had some impact on crown of thorns populations because fish eat starfish. But the outbreaks are not due to predator release, they are caused by prey abundance.

Crown of thorns starfish outbreaks are due to increased survival rates among baby starfish. Algal blooms provide superabundant food for the larval stage of starfish life, allowing populations to explode beyond the capacity of fish to clean them up. Algal blooms are the consequence of high nutrient and sediment loads from cleared, fertilised and urbanised catchments.

Nutrient loads are now five to nine times higher in rivers than before European settlement. The lesson is that the water quality of our freshwater systems directly affects the water quality of our marine environments. The same problems caused by nutrients in inland waters are caused by inland waters providing nutrients to the ocean: algal blooms fundamentally alter the food web. In this case, extra algae means more crown of thorns starfish, which means death for coral reefs.

Link between land and sea

The good news part of this story is the author’s prediction that if crown of thorns starfish are controlled, the Great Barrier Reef would be able to recover from the other two causes of coral death. This means that people who live on the land have both a responsibility and an opportunity to make a difference to global health.

Protecting marine habitats and environmental management of the Great Barrier Reef is not enough to save it. The ocean is not as distant from inland environments as most people think. You do not have to have an ocean view or be addicted to seafood to see the benefit of preserving our marine estate. Let me use myself as an example: my home is over a three hours drive from the ocean, I don’t eat fish at all (vegetarian for 33 years so far) and I am the first person to get seasick if I do get the opportunity to go boating. And yet I cannot ignore the plight of the reef that flanks our continent, or the waters that support life as we know it. As a thinking person I know that a healthy ocean directly impacts my family and my future.

People who live far from the ocean have the power to save or destroy this World Heritage Site. Saving our oceans starts on the land, in the home, in the factory and on the farm. What we pour down the drains or spray on our soil inevitably finds its way into our freshwater systems, and they deliver the bounty of our activities to the sea.

Better management of our rivers and streams will benefit the native fish and habitats close to our homes, as well as giving the reefs and seagrass beds and other marine habitats a fighting chance. The payback for us is those ecosystem services, at once invisible and indivisible from our own health and well being.

Unfortunately, ecosystem services, like fresh air and clean water and food security, are easy to take for granted. But we will miss them like mad when they are gone. Just remember that you are not powerless to make a difference, in fact, the truth is quite the opposite. Only you, and others like you (human beings, that is) have the power to protect planetary health. Caring for the world’s heritage begins at home, no matter how far you live from a World Heritage Site.

Today’s announcement of the marine parks is a significant step forward in the conservation of the southern oceans. Australia is now the world leader in the protection of marine environments, but the decision has not come without controversy and quite a bit of emotion.

Not all areas with the marine parks will have the same restrictions. Some areas within the park will ban oil and gas exploitation, others will have restrictions on the type of fishing gear that can be used, and about 13% of the total 2.3 million kms will be no take zones, setting up sanctuaries where all forms of fishing or extraction are banned.

Recreational and commercial fishing groups have been vocal opponents of the marine parks, despite the promise of $100 million worth of compensation for the commercial fishery and the relatively small number of areas where recreational fishing will be banned.

Certainly some fishers will be negatively impacted, and I hope they get a fair price for the loss of business, but in the long term most of them are likely to benefit. There is strong evidence that setting aside sanctuaries increases the numbers of fish. Coral trout, in particular, have benefited from no take zones in the Great Barrier Reef, and because fish do not stay within the sanctuary, fish numbers increase in adjacent areas. A recent study showed that only 28% of a reef can produce 50% of the larval recruitment. This is because fish in sanctuaries are not only more abundant, they are able to grow to a larger size, producing more offspring per individual.

In other words, marine reserves are effective in increasing fish stocks.

The fisheries minister in Queensland has complained that the reserves will destroy local business and not produce any environmental benefits, saying the initiative will be lose-lose. I think he is wrong and that in a few years people will acknowledge that the decision to establish a network of marine parks is win-win.

Taking a good look at the environmental challenges facing our oceans is depressing; we face some daunting statistics of decline and there are few obvious solutions. But when others have done the research they come to the same conclusion as Tony Burke and our federal government: a system of National Parks in the oceans is a good idea.

This week we learned that a member of the Science, Space and Technology committee in the United States House of Representatives does not believe in science. Paul Broun, a Republican from Georgia, probably earned the post on the committee because he is scientifically trained; he has a B.S. in Chemistry from the University of Georgia. However, during a recent speech to a church group he said, “All that stuff I was taught about evolution, embryology, Big Bang theory, all that is lies straight from the pit of hell."

Paul Broun was speaking to a church function, so his remarks were well received on the night, but within days of the remarks going public, over 40,000 people signed a petition seeking to remove him from the committee. I guess that many people do not want to have someone on the Science, Space and Technology committee who does not believe in the basics of scientific process and critical thought.

If a powerful politician thinks that key scientific theories are lies designed to keep us from embracing certain religious truths, then there is no opportunity for thoughtful debate and evidence based policy. Indeed, when Paul Broun said that the earth is less than 9000 years old, he was expressing an opinion that was not well argued (not argued at all) and does not deserve to be taken seriously. A recent post on this site explained the danger of allowing everyone to have ill-informed opinions.

In the same vein, just few months ago, the Texas Public School system decided not to teach higher order thinking or critical thinking skills, because they “have the purpose of challenging the student’s fixed beliefs and undermining parental authority.“ This is another blow for science and thoughtful discourse, but possibly even more frightening, because it supports the idea of denying young people the benefit of an education. If they are not allowed to learn the difference between thinking and doing what they are told, then we are creating a generation of disempowered, helpless idiots.

Unfortunately, they may grow up to become powerful politicians themselves. Paul Broun is not alone in his ignorance of science. Many other members of the Science, Space and Technology committee have made statements that indicate anti-scientific views or deep misunderstandings of science, as pointed out by Wired.

But the thing that is really disturbing about both these cases is not the muddy thinking or the lack of evidence based arguments. The point of Representative Broun’s comments and the decision by the Texas School system is that religious views are more important than common sense. This is particularly true when politicians feel that waving the Bible around will secure votes in a conservative electorate, or when a community that lacks religious diversity can get a group of educators to agree on what ideology would be best for our children.

Ironically, both of these views are being trumped by yesterday’s news that the fastest growing religion in the USA is no religion at all. Apparently, the number of people who are not affiliated with any church group has increased 25% in the last five years, and this is more prevalent among people under 30. These “nones” are becoming a political force in their own right, worthy of pandering to if you are campaigning for office.

Apparently, the “nones” are not all atheists. Many espouse a belief in God or a desire for spirituality, but they do not want to be associated with the church of their parents or a religion that expects them to act like idiots. Probably they are not willing to believe that science consists of lies from the pit of hell. Hopefully they are capable of critical thinking, and are looking for leaders with some skills in this area.

This is an exciting time to be a human being. We’ve got the old way of thinking, the religious fundamentalists, driving a section of the Republican party and many political parties across the world. These groups may be motivated by a fear of hell and are united in a disdain for secular humanism and critical thought. Like Paul Broun, these people still think that the Bible (or Koran, or Talmud) — books written thousands of years ago — should drive public policy in the 21st century.

Fortunately, there are new ways of thinking coming to the fore at this time. Religious affiliation is not as important to young people, who share their ideas and opinions more widely than any other generation. Online friendships allow people from different cultural backgrounds to gain new perspectives and take a wider view, and political movements are jumping across national borders and shaking the globe.

In a changing world, the ability to frame an argument and base it on evidence is a powerful skill. Unfortunately, religious traditions also have power, especially to politicians who use religion to justify their own positions and ideas.

Paul Broun may have been elected in part because his religious views reflect those of many members of his electorate. Unfortunately, his scientific views could harm his constituents, particularly if decisions about science policy are made without the application of evidence based thinking.

This is a great opportunity to point out again that not everyone is entitled to their opinion.

Yesterday, in the wake of the banning of the super trawler, Australia’s Nobel Prize winner Brian Schmidt called for a more scientific approach to policy. He pointed out that in Britain, science is embedded in every government department, while in Australia, public confidence in scientific advice has been damaged.

Today, a member of the Small Pelagic Fishery Resource Assessment Group, which makes recommendations about quotas, said that the doubling of the jack mackerel quota occurred for economic, rather than scientific reasons.

This puts science in an awkward position. When policies are justified by science, the public has every right to expect that the evidence was collected in a manner appropriate to the question, and that conclusions were based on data. Science must be both rigorous and independent, if it is to be trusted.

Unfortunately, saying that changes to the jack mackerel catch limits were based on “the best available evidence”, is not very comforting in this case. This is not to say that the scientists did a poor job of analysing the data. Indeed, the scientific report* used to justify the adjustment urged due caution because the egg survey was designed to study spawning dynamics of blue mackerel and the data were therefore not collected at the right time or in the right place for optimally estimating the biomass of jack mackerel.

The Australian Fisheries Management Authority website defends the decision by saying: “AFMA uses the best available science to set catch limits and seven of Australia’s and the world’s leading fisheries scientists have publically (sic) supported the science.”

There is nothing wrong with that statement, except that it implies that the world’s leading fisheries scientists support the catch limits set by AFMA. The scientists might be dismayed at the way the research has been used (or ignored) but they have every right to defend the science.

The question is not about the science, but about the application of the science. The Resource Assessment Group within the AFMA had the task of reviewing the science and making a recommendation about total allowable catch for these species, and a member of the group has told us that the decision was not based on science.

To be more precise, Graham Pike said in The Australian: “Seafish Tasmania Pelagics, was registered on April 21, about a month after AFMA (wrongly) doubled the jack mackerel quota to economically justify the venture.” This was not a failure of science, but of the interaction of science and policy.

The AFMA defends the super trawler by adding, “There is no evidence that larger boats pose a higher risk to either commercial species or broader marine ecosystem.” This is another statement that does disservice to the science. It is written as if the research has been done and no evidence was found, rather than admitting that no data has been collected about the impact of larger boats. It seems to imply that the people who oppose the super trawler must prove that big boats pose a higher risk, rather than acknowledging that it is the responsibility of Australian fishery managers to determine the risk.

Both of these statements could be used in a classroom as examples to teach critical thinking. They are very similar to logical fallacies known as ambiguity and burden of proof. Scientists are trained to spot these types of errors and avoid them in their own thinking and writing. Politicians are trained to employ these types of statements, particularly when they are engaged in an activity known as “spin”.

Fisheries managers serve the politicians and employ the scientists. They live in a strange no man’s land where political spin is not normally necessary and science is someone else’s job. And yet, as Brian Schmidt said, the public confidence in AFMA has broken down.

Perhaps this is a good time to seriously consider more scientific advisers to government at all levels. Imagine the benefits of introducing critical thinking, rigorous logic and independence into every department and agency. If the goal is to restore the public’s confidence in decisions made by government, then the first step is to recognise that the public knows the difference between evidence and spin.

So please don’t give us evidence that decisions were based on spin. The trick is to spin it so that we believe that decisions are based on evidence.

• Neira, F. J. (2011). Application of daily egg production to estimate biomass of jack mackerel, Trachurus declivis – a key fish species in the pelagic ecosystem of south-eastern Australia. Final report to the Winifred Violet Scott Charitable Trust. Fisheries, Aquaculture and Coasts Centre, Institute for Marine and Antarctic Studies (IMAS), University of Tasmania. 42 pp.

The report in this morning’s paper about complaints to the Fisheries Minister by members of the group that set the quotas for the small pelagic fishery highlights the challenges of setting fishing quotas.

The conservation and recreational fishing representatives on the Small Pelagic Fishery Resource Assessment Group asked for an investigation of the decision to double the total allowable catch of jack mackerel back in June. Without this decision, there may not have been enough fish stock available to attract a super trawler to Australia.

As members of the group, it was part of their job to assess the science behind the decision, so they would have read the relevant research. Nevertheless, Senator Joe Ludwig declined to hold an inquiry. This raises the question: how do we assess the adequacy of scientific research in areas where society, politics, industry and emotions are involved?

This is not a new problem, but it does seem to come increasingly to the fore. Just yesterday, another article in The Conversation addressed the problem of which comes first: science’s assessment of data or society’s need for knowledge? The answer lies in the interface between. Society decides, through agitation, curiosity and approval of funding, which questions scientists will address at any given time. Science is not something that happens in a vacuum. The case of the super trawler and the fishing quotas is an excellent case in point.

The Australian Fisheries Management Authority has posted information about the decisions made by them about the super trawler on their website. It is very useful, providing a table showing the total allowable catch for various fish species in the small pelagic fishery that would be targeted by the super trawler. For the past five years, these quotas have either stayed the same or been reduced, with one notable exception. The eastern jack mackerel fishery had its allowable catch increased from 4,600 tonnes in 2011 to 10,100 tonnes in 2012. This is the dramatic change that upset two members of the resource assessment group.

Fisheries scientists have posted a paper on the AFMA website outlining the background to the scientific issues. They explain how the harvest strategy is more cautious when the available data are out of date. This is important because all of the data are several years old. This situation is probably unavoidable given the complexity and cost of assessing fish stocks.

Estimating the biomass of oceanic fish is not an easy task. The adjustment of the jack mackerel quota was based on a survey of fish eggs, which are drawn from the ocean in plankton nets across a wide area, followed by mathematical calculations designed to estimate the average egg production. The last survey of jack mackerel eggs took place in southern NSW in 2002, and rather than complaining about the applicability of 10 year old surveys to current fish stocks, the scientific debate revolves around which algorithm should be used.

Another helpful document on the AFMA website is a report on the small pelagic fishery in 2010. This provides a comparison of the total allowable catches with the actual catch, giving us an insight into how much of the quotas are actually fished. In 2008/2009 the combined allowable catch for redbait, blue mackerel, jack mackerel and sardines was 46400 tonnes, but fishers only caught 5130 tonnes. In 2009/2010 the combined allowable catch was 35600 tonnes, and fishers caught 2482 tonnes. So, in recent years in the southern pelagic fishery, the average catch was than 10% of the total allowable catch.

This is good news if you are worried about overfishing, because it means that none of these stocks have been over-exploited in the recent past. But it is bad news if you are thinking about these fish as a resource, because from an industry perspective these fish are not being fully utilised. No wonder somebody thought it was time to get a bigger boat.

The super trawler could be a game changer, providing an open ocean fishing method that actually harvests most of the total allowable catch. The increase in quota, combined with the prospect that it is finally achievable, concerns me.

It is an unfortunate aspect of the industry that fishing companies such as Seafish Tasmania are the ones who pay for and provide practical research support (such as collecting the egg counts) for the assessment of fish stocks. It would be better if our biomass estimates were based on regular, independent monitoring. If society is interested enough, perhaps they will find a way to ensure that there are funds to do this important research.

But the research is not the end of the story. How we represent it in committees that make the decisions, how our Minister responds to concerns, and how the community understands these issues are all critical to the implementation of fishery science.

Our Federal Environmental Minister has stepped up to the plate. He has exercised every legal avenue open to him to regulate the super trawler currently known as the Margiris when it begins fishing in Australian waters.

Tony Burke said, “What I’ve signed off on today is effectively the big vessel will have to fish with the rules so that the impact that it has on the environment is no more than if it were fishing as a small vessel.” I wonder how small a vessel he has in mind. Did he read my recent post about the super trawler where I complained that the super trawler could take as many fish in a day as 56 traditional African fishing boats (canoes, really) can take in a year?

Or should we be concerned that a member of the Commonwealth Fisheries Association claims that smaller boats catch more by-catch than the big boats? If this is true, then Tony Burke has pulled a swift one and increased the by-catch for the big boat while making it sound reasonable to the concerned public.

In either case, I applaud the plan to put observers from the Australian Fisheries Management Authority on the super trawler, to place fully monitored cameras in the nets, and to bring in European experts to check the nets. One risk of super trawlers is their ability to do enormous damage to threatened species, both because they have the capacity and because they operate in the open ocean where their practices are not observed. Observers that submit daily reports, and will review the restrictions again in two weeks, are a really good idea.

In addition, whenever one dolphin or three seals are killed, the boat will have to suspend operation, pull in its huge nets, and move 50 nautical miles (over 90 km) to a new location. This will cost them a lot of money and time, so I am amazed to hear the director of the local company say in the Financial Review that he is happy with these restrictions. If it is true that we can get super trawlers to adhere to these rules, and if it actually does reduce by-catch to extremely low levels, then half of my concerns about its operation will be addressed.

Of course the thing that excites me is that not only will fewer seals and dophins die, but that we will be collecting data that could shed light on this debate. I hope the data will go beyond the mammalian bias shown here. We need to count the penguins, albatross, turtles and non-target fish that are affected. But as a scientist, I will be greatly relieved to see some actual figures about the impact of this boat in Australian waters.

Some people say that no by-catch is acceptable, and that if one mammal (or penguin or turtle) dies then the whole operation should be suspended. The leader of the Greens, Christine Milne, has criticised the regulations on this basis, but all this does is prove that Christine has never gone fishing. Some by-catch is unavoidable, and the only way to impose a no by-catch rule is for all of us to stop fishing right now. We might as well say that because road kill is unacceptable, nobody should drive cars anymore. It is an argument that does not hold water.

Given this madness, I am pleased to see that the Recreational fishers are joining forces with the Greens, at least down in Tasmania. I am hoping these groups can learn things from each other. Things like: a no by-catch rule is a pipe dream, and: not all greenies are completely mad.

Still, can we trust the observers that are going to be placed on the boat? The industry works so closely with the government that there is a risk of non-independence. The most recent allegations that the director of Seafish Tasmania, who brought the super trawler to Australia, was a member of the government advisory panel that set the quota for this fishery, is disturbing.

Because the other half of my concern about the super trawler is the risk of overfishing. The pelagic fishery that will be targeted by the super trawler in Australia is made up of species that are larger, longer lived, slower growing and higher on the food chain than many pelagic fisheries. Estimates of the biomass available for harvesting are based on old information, inference, and in some cases, no information at all. It is a guessing game that can be easily swayed by personalities, loyalties and economic arguments. But losing this game can have dire consequences for hundreds of species, including us.

It is exciting to read that in addition to all his efforts so far, Tony Burke still holds out hope that he can eventually ban the super trawler. To do this Labor will have to introduce a private members bill to change federal laws.

I, for one, am happy with the Minister’s response to the super trawler issue thus far. Although I signed the petition and donated money to the cause, I never thought we’d get this far. Well done, Australia.

A reader complained that my last column about the environmental damage caused by super trawlers was too emotive. We agreed about the facts, but not about how to frame them. I tried to ignore this comment, but it kept bothering me, and for different reasons on different days.

After some rumination, and conversations with colleagues, I have decided to address it. Must serious conservationists avoid using their hearts? Do we do better science when we only use our brains? Is our advocacy for the planet best framed in dry factual statements? I think not, and my reasons are varied.

Reason one: science communication often suffers from a lack of emotive content. Yesterday, a colleague sent me a link to an article called three tips for science communication, in which the author complains:

“It dismays me how scientists – so full of passion and creativity – sometimes make the wondrous mundane, and the story of their work stripped of emotion.”

Part of my life’s goal is to share my enthusiasm for science and the species with whom we share our planet, and being told that I need to be wary of wearing my heart on my sleeve is frustrating. I want to keep my heart where it belongs, right here in my chest, but I want it to be part of my work. Otherwise, how can I convince non-scientists that I speak from a place of truth and honour? My integrity is firmly embedded in my passion for this thing called life.

Reason two: science is more fun than most people realise. I know from personal experience that scientists are passionate, emotional creatures. We get really excited about apparently esoteric stuff, but when we explain it, we get our students, friends and families excited too.

I have often been on field trips where we meet unique, endangered creatures, and the students do not realise how special the moment is until the senior staff’s excitement becomes apparent. If scientists do not share their emotional responses, they are not truly teaching.

Scientists, like everyone else, do better work when they put their whole person, body and soul, into their work. The world needs more people to learn and use the scientific method, but this won’t happen if people think they have to check their hearts at the door. If we portray ourselves as merely walking brains, how are we going to convince others to join us, and become scientists, too?

Reason three: my environmental students are afraid of being labelled as greenies. I think this is the crux of the problem. Young people who want to save the planet and protect our environment enrol in a degree in science so that they will have the knowledge and credentials to make a difference. But to do this they feel they must reject the extremes of some in the environmentalist movement.

I can illustrate the problem with a conversation I had about a year ago. I rang someone (in government or industry, I forget the exact issue) and introduced myself as a conservationist. The person on the other end began with, “You people”… and began to tell me what I thought, almost none of which was true. When I managed to break in and explain that I was a scientist who had been doing research in the area and had hoped to offer some useful suggestions, the individual calmed down and said, “Oh! You mean that you are a conservationist!” … as if I should have said so. Except that I had.

Conservationists are therefore somewhat twitchy, and as a group we are schizophrenic. We feel compelled to express our concerns about the environment in a way that distances us from other people who care about the environment. Some of us work from a scientific framework, base our arguments in logic, and seek solutions that are acceptable to society. Others are looking for fundamental changes to society as we know it, and are willing to take radical actions including vandalism. Most environmentalists are somewhere in between.

Is our language too limited to encompass this diversity? Or are we just too sensitive about the words people use? Personally I don’t mind being called a tree hugger, but the derogatory connotations of the phrase are both undesirable and incorrect.

What annoys me most about all this is that a physicist can get as excited and emotional as they like about landing a car on Mars, but a conservationist has to tread lightly when they express concerns about the extinction of a species or the impact of an industry that is destroying the environment.

I love fish, and I love fishers. People who harvest the bounty of the planet’s waters often know their fauna intimately and are deeply concerned about threats to the natural system that supports them. This does not, in my mind, include people who run the floating factories known as super trawlers.

Can we find a way to support both the fish and their fishers by careful management of our rivers and oceans? I think we can, but we need to be able to have a frank discussion about the impacts of certain fishing practices, the politics of fishing regulations, and the importance of sustainability.

To do this, we will have to carefully manage our emotional responses to people with alternative views. But that does not mean that we have to pretend that we are emotion-less.

I want to thank the reader whose comment got me thinking about this issue. And I want to thank the readers who are going to comment on this post. Let’s have a proper conversation about the nature of conservation.

Protests on the weekend in Hobart against the Dutch owned super trawler, the FV Margiris, have led to the Australian environment minister, Tony Burke, expressing some concerns. Greenpeace’s petition against the super trawler is clearly having an impact.

The super trawlers are boats that should never have been built. They are anti-sustainable in design and devastating in their implementation. This particular boat recently caused the collapse of fish stocks in West Africa such that Senegal has recently banned all super trawlers. Ironically, the European owned boat processed these fish and sold them back to African markets, thereby raping not only the environment, but the economy, of their host nation.

But why such concern about a single boat? It would take 56 traditional African fishing boats a year to harvest the number of fish this boat can remove from the seas in a single day. A small crew of 40 people will get just one days wages for this fishing effort, as compared to the hundreds of local fishers who would have received wages for a whole year. In Australia, the quota of fish allocated to this super trawler is half of the entire allowable catch in the area. This is economically unsustainable.

The by-catch, or random killing of non-target species, is much higher in the automated fishing operation of a super trawler than in any other type of fishing. Dolphins and seals are killed directly, and the removal of vast quantities of red bait and mackerel impacts the ecosystems where these boats fish by destroying the food chain that supports tuna, sharks, seabirds and mammals. This is environmentally unsustainable.

Managing the legal and political impacts of these trawlers is proving too much for most nations. As Tony Burke pointed out, last year a Korean super trawler over-fished their quota in New Zealand, causing harm to Pacific mackerel stocks. The captain of the super trawler fled the country and was convicted in absentia, but this does not bring the fish back.

I would suggest that there are no political, economic or environmental solutions that could make super trawlers sustainable. They are literally a juggernaut: mercilessly destructive, and virtually unstoppable. Once built, the economy that released them on the world will demand that they achieve their dreadful potential.

All we can hope is that governments find the will to make it illegal to use these boats anywhere in the world.

Oh, and if you want to add your name to the petition, use this link.

The WCPFC (Western and Central Pacific Fisheries Commission) is meeting this week in Korea in an attempt to regulate the world’s largest tuna fishery. An earlier attempt in March this year failed to get hundreds of delegates from dozens of countries to agree on how to prevent overfishing and ensure the sustainability of an industry worth $US 5.5 billion last year.

Several island nation members rely entirely on this fishery for their financial viability, and all of them rely on the management of fish stocks to ensure a future for the industry. Nevertheless, the complexity of the task is proving overwhelming. Conservation scientists have not prevailed despite widespread agreement on the need for action.

How complex can it be? The Commission was established in 2004, after six years of negotiations. It comprises members from 25 countries and 8 territories, as well as 11 cooperating non-members, for a total of 44 different political viewpoints.

The commission is responsible for management of a part of the Pacific Ocean that is over 10,000 kilometres across, or almost 20% of the earth’s surface. They manage the fisheries of five species of tuna (albacore, bigeye, bluefin, skipjack and yellowfin), three species of marlin (black, blue and striped) and the swordfish. Each of these species has unique behavioural patterns, feeding grounds, and conservation issues.

In 2011, the tuna catch was 2,244,776 tons, which comprises 79% of the total fish caught in the Pacific Ocean, and 55% of the global tuna catch. Globally, at 4,077,814 tons, the tuna catch was the lowest in 10 years.*

These fish are caught using 10 different kinds of gear or approaches (trap, gillnet, harpoon, longline, pole and line, troll, hook and line, purse seine, recreational and trawl). Of these the purse seine fishery is currently the dominant one, with the number of vessels and effort (traps set) at an all time high. Despite this, last year the purse seine catch was the lowest for 3 years.

The fish targeted by this industry are not the only victims of the fishing industry. By-catch is unavoidable most of the time, and the species that die as a side effect of all this fishing include whales, sharks, dolphins, rays, octopus and squid, turtles, seabirds and other fish.

Five species of sea turtles are affected, three endangered and two critically endangered. Leatherbacks are more likely to be caught by longlines, while the Olive Ridley turtle is taken most often by purse seiners.

Nine species of dolphins and nine species of whales are affected. The three most commonly caught species are spotted dolphins, spinner dolphins, and common dolphins. In 2011, a total of 986 dolphins of those three species were killed by the fishery. On the other hand, some species of dolphins, such as the short-finned pilot whales, have increased in abundance in recent years, possibly because of the decline of their competitor, the spotted dolphin.

Sharks and rays are common by-catch in the tuna fishery. Silky sharks and white-tip sharks are the most affected, but hammerheads, thresher sharks, makos and the enormous whale shark are also impacted. In addition to the six shark species, several species of manta rays and stingrays are commonly caught and killed.

Over 100 species of seabirds fly over the Pacific, many of which rely on prey driven to the surface by schools of tuna or dolphins. Albatrosses and petrels are susceptible to being caught by baited hooks on longlines, because they are adapted to scooping fish up from the ocean’s surface. One study estimates 40 seabird mortalities per million hooks on longline vessels. Many albatross species are endangered, and all of them are affected by the tuna fishery.

I could not figure out how many species of squid or octopus were implicated, although they are commonly found in the fisher’s nets, much less the countless smaller creatures that lie at the bottom of the oceanic foodweb: jellyfish, phytoplankton and zooplankton.

The total number of species affected by the decisions made by the WCPFC is large: hundreds of vertebrates, thousands of invertebrates, and who knows how many plants and algae.

But one of those species is us. The delegates at this week’s meeting have over 100 papers to read, 39 reports from member countries, and dozens of important decisions to make. These decisions affect the economies of nations, the fate of individuals and businesses, and the future of the Pacific Ocean ecosystem.

When we are harvesting limited natural resources such as the ocean’s fish, careful management is the difference between a future for the industry and a complete devastation of our planetary plenty.

We wish the commission the very best of luck, because this is not just a numbers game. It is a cruel calculus, affecting us all.

*The measurements in this paragraph previously read “megatons”, but have been corrected.

Lonesome George was a giant tortoise, the last of his species, and he died this week, on Sunday (24 June). I wrote about his death and made everyone sad in a recent post.

George was found living alone on a tiny rocky island called Pinta. He had been there a long time, presumably alone for most of his life – he was 60 years old. His species had been hunted by humans a hundred years before he was born, but the death knell came when goats were introduced to Pinta Island. Goats can eat hundreds of times faster than tortoises. The goats quickly removed the native vegetation, so there wasn’t even enough for thrifty and slow-munching reptiles.

I want to thank Fausto Llarena, who was Lonseome George’s keeper for 40 years, on behalf of my species. He showed compassion and companionship to this animal who was the last of his species. We may have caused the decline of his kind, but at least one of us treated him with kindness.

It means a lot to me, and to all of us, that we have this ability to care for other species. But there seems to be a limit to our generosity. While we can be keenly aware of our impact on one animal in an enclosure on the other side of the world, it is harder to see the daily impact we have on animals in our own neighbourhood.

The best response to our feelings about exotic animals going extinct, is to see what we can do for our local native creatures. We can open our eyes to the various ways in which our behaviour might harm the species with whom we share our environment. We rarely hunt things to extinction on land anymore (we are still hard at it in the oceans, unfortunately), but we do release a lot of metaphorical goats.

Livestock of all kinds encroach on native habitat. Growing crops uses land that could support native fauna. All introduced plants and animals are like the goats released on the island of Pinta – they exclude the species that were originally here.

Each spot on our planet has its own complement of native species, and too often the people who recognise how special they are live on the other side of the planet. We have a tendency to take for granted the creatures we grow up with. I thought squirrels and salamanders were boring until I moved to Australia, where we have neither. I thought kangaroos and possums were exciting until I moved to the country where they are practically pests.

The trick is to nurture the special creatures that live in their own backyards, even when they annoy us. There are so many simple things we can do, like planting trees or putting aside land to make space for local creatures.

Doing this will foster in each of us a sense of place, a spirit of peace, and a deep connection to this thing called life. For better or worse, we are all part of it.

Lonesome George, a Galapagos Giant tortoise, died a few days ago. He was the last individual of the species Chelonoidis nigra abingdon, or the Pinta Giant Tortoise, so his demise is also an extinction.

George was found alone on Pinta Island, one of the smallest islands of the Galapagos archipelago, in 1972. These large land tortoises were hunted to near extinction in the 19th century, and the introduction of goats hastened their decline.

Both Lonesome George and his species died before their natural lifespans were complete. At 100 years old, George was only middle-aged. Although scientists will attempt to discover the cause of death, he may have died of a broken heart.

After his discovery in the early 1970s, George was transferred to the Charles Darwin Research Station, where every attempt was made to save the species. Researchers offered a $10,000 reward for anyone who found a female Pinta Giant Tortoise to mate with George, without success. They introduced George to females from closely related species.

Female tortoises from Isabela Island (of the species Chelonoidis nigra becki) lived with George for 15 years, and he did attempt to mate with them, but the eggs were inviable. More recently, George was living with two female tortoises from Espanola Island (a more closely related species known as Chelonoidis nigra hoodensis), but I don’t think he even attempted to mate with them. George may have been hampered in the romance department by a lack of social skills due to having grown up all alone. Or maybe, because the offspring would not have been the same species as their father, he did not see the point.

Either way, the species was effectively extinct when it was down to a single individual. We had a similar situation in the 1930s when the last Tasmanian tiger was held in the Hobart Zoo. If you watch the film of the last Tasmanian tiger, you see a restless individual, whose longing for companionship or wilderness is strong. Compare this to a film of George who greets his keeper with a modicum of enthusiasm.

How does a tortoise express its longing? When mastication is an indication of activity and all movements are methodical, our ability to empathise is limited. But Lonesome George was in the Guinness Book of World Records as the loneliest creature on earth.

Lonesome George’s demise leaves me feeling a little lost and sad. After all, it was human activity that decided his fate. It is both sad and creepy when your death is noticed only by the species that caused your extinction.

Even this eulogy feels inadequate, because it should be written in Pinta Giant Tortoise, a language that nobody on earth knows anymore.

Two men walk into a bar. The first man says “I would like a glass of H2O.” The second man says “I would like a glass of H2O too.”

It’s funny because H2O2 is the chemical name for hydrogen peroxide, and hydrogen peroxide is inimical to life. I don’t recommend drinking it.

Is this joke chemical or biological? I think it is both: it is about the interaction between chemical toxins and this thing called life. But there is another level of biological organisation that is important to the outcome. The person that tends the bar is an important component of the equation.

What will the barmaid do? Will she hear the “too” and give the second man water? Or will she hear the “two” and serve a clear liquid that is lethal? Perhaps she has good reason to serve water instead of peroxide. She might not have any on the shelf, or the bar may have a policy of locking up dangerous liquids, so as not to harm themselves or their customers.

A recent paper describes a natural situation where the barmaid’s decision renders the environment benign. The story takes place in the open ocean, where single cells known as plankton produce energy and oxygen through photosynthesis. Excess oxygen tends to increase the levels of H2O2. These tiny organisms protect themselves by releasing a protein called catalase-peroxidise, which breaks down hydrogen peroxide.

But one crafty bacterioplankton known as Prochlorococcus takes advantage of the other plankton by letting them do the costly energetic work of making the open ocean safe for cells. Prochlorococcus has lost the gene for catalase-peroxidase.

Gene loss is usually an undesirable outcome, most often occurring through a process known as drift. Drift happens by accident, and rarely increases the survival prospects of the organism. But this is a case in which the gene loss is adaptive, and not accidental. Natural selection has responded to the low nutrient environment by choosing cellular efficiency. This decision is possible because of other plankton species alter the chemistry of the ocean to make it safe for themselves.

The authors call it the Black Queen Hypothesis, after the Queen of Spades in the game of Hearts. Getting passed the queen drastically raises your points in a game where the low score wins. Prochlorococcus has lowered their own score by reducing their energetic output, and they have done this by passing the cost on to their distantly related cousins.

This species could shed an essential gene because the other organisms in the environment act like a friendly barmaid. Customers are served water even when they accidentally order hydrogen peroxide.

Contrast this situation to one where the other organisms are hostile. If the barmaid is likely to serve hydrogen peroxide, then species need to keep on their toes and hold onto their genes. Too often the biological component of the environment is antithetical to a species’ survival. Predators, competitors and parasites are always looking for ways to take advantage.

This evolutionary scenario is known as the Red Queen Hypothesis. The Red Queen in Alice in Wonderland said, “It takes all the running you can do, to keep in the same place.” The fact that a species’ enemies are evolving as fast as they can to feed on them creates an environment in which every new gene is potentially critical.

Just last year, some researchers found that parasitism may be responsible for sex. And you thought parasites never did anything for you! The Red Queen produces an environment in which new genes are favoured, and sex is important because it is designed to create new genetic combinations at every generation.

Evolution is about adaptation to the environment, but the environment is not limited to air, water, and soil. The environment includes other living things that affect our own survival as surely as the presence of toxins or the availability of water.

It all depends on whether your barmaid is a Black Queen, who takes the Queen of Spades from your hand, or a Red Queen, who looks for every opportunity to do you harm.

So watch what you drink (water is good), surround yourselves with friends to whom you can sometimes pass the costly black card, and try to frequent bars with friendly staff.

References:

Morris JJ. Lenski RE. and Zinser, ER., The Black Queen Hypothesis: evolution of dependencies through adaptive gene loss, mBio 3 March/April 2012.

Levi T. Morran, Olivia G. Schmidt, Ian A. Gelarden, Raymond C. Parrish II, Curtis M. Lively, Running with the Red Queen: Host-Parasite Coevolution Selects for Biparental Sex. Science, 2011; 333 (6039): 216-218

The Australian government today has announced a series of marine reserves that will make Australia a world leader in ocean protection. The reserves will cover over 3 million square kilometres, or nearly a third of Australian waters. Commercial and recreational fishing will be restricted or banned, and other activities such as mining and gas recovery will be limited.

This is a wonderful news story about which every Australian should be proud. It will protect habitat for juvenile fish, prevent damage to coral reefs and sea grass beds, and increase the outlook for many large species such as sharks, whales, tuna and marlin. Research on the impact of reserves has shown that they are more effective than expected in driving the recovery and sustainability of fish populations.

Unfortunately, the news cycle has been negative. The conservationists are unhappy, because the proposal does not go far enough. The fishermen are unhappy because the compensation may not be large enough. And another author on The Conversation is concerned that the reserves will not protect the World Heritage Listed Great Barrier Reef because coastal development and gas exploration continues outside of these reserves.

I am sure that all these people have a point, but let’s remember which problem we are addressing. The degradation of oceanic ecosystems affects all of us, and commercial fishing is a large part of the problem. As fishing boats get bigger and more sophisticated, fish that were formerly protected by living in remote areas or deep waters are now regularly harvested. Some fishing practices, such as trawling, damage the sea bed grasses and coral that provide habitat for juvenile fish. The overall impact of oceanic fishing is a decline in fishing stocks and a general decline in the health of oceanic ecosystems. The ocean is a shared resource. We all need to look after it.

So although the reserve system might have been larger and done more to protect our fisheries and marine ecosystems, I still think this is impressive, world class effort. Let’s praise the government for taking a bold move that makes Australia a world leader in the conservation of marine environments.

And although the compensation may not, at this stage, seem like enough for the fishers who have to face uncertainty and job losses, let’s not forget that this policy contains substantial payback for that industry. Protecting our fish stocks into the future will mean that some fishers will be able to pass their livelihoods on to the next generation. This might not have been the case if overfishing and habitat destruction continued at current rates.

And for those who say that this will hurt our economy, remember the huge impact of tourism, and consider that this may only increase in a world where healthy marine ecosystems are getting harder to find. The reefs, the whales, and the magnificent clear waters of this great southern land will continue to attract tourists long into the future.

The next step is to turn toward the land-based conservation measures that will protect our oceans. Coastal development, pollution and rubbish need to be controlled. These are not affected by the marine reserves, but nothing is stopping us from addressing these issues in due course.

Tony Abbott, of course, wants to complain as well. He is quoted as saying that he is “Instinctively against anything that damages recreational … and commercial fishing.” But his instincts are wrong.

Research supports this initiative, and fishing outside of the reserves will be more successful and more sustainable because of it.

I began writing a series on sex cells when I heard about hammerhead sharks giving birth without the benefit of a male. This type of reproduction is called parthenogenesis, and I tried to explain it, in part, by referring to the Parthenon.

Each row of columns in the Parthenon represents a set of chromosomes. In most cases, an organism needs at least two sets to be able to support a whole organism. The analogy works because you would need two sets of columns to keep the roof on a structure.

Sex cells are interesting because they serve as a chromosome delivery system to the next generation. Normally, these special cells carry only one set of chromosomes. They need to join up with another sex cell to create an embryo.

I have been writing about the exceptions to the rule. In the case of the hammerhead shark, an egg joined up with another cell from the female shark to produce a virgin born shark. Let’s call this true parthenogenesis.

In the case of the Amazon molly, the all female species has eggs that double their own chromosomes to produce a clonal offspring, but they require the stimulation of mating to turn their eggs into embryos. No actual fertilisation takes place, however. This type of reproduction is called gynogenesis.

I want to explain a third type of unusual reproduction called hybridogenesis. It is an apt name for what some fish do: they not only let their sperm hybridise with their eggs, they are hybrids themselves. Some species have two different species’ chromosomes inside their nucleus, and others (the rare triploid species) have three!

Hybridogenesis occurs in several species of the genus Poeciliopsis. Unfortunately, they do not have a common name, and their scientific names are long because they include the names of both of their species of orgin (for example, Poeciliopsis monacha-lucida). Hybridogenetic species actually let the sperm fertilise the egg, but it is a cruel trick, because the male genes are not incorporated into the offspring.

It is an amazing trick, accomplished by the failure of the female cell to recognise the chromosomes of the males. Structures that usually attach to the chromosomes and pull them around the cell fail to recognise chromosomes that came from outside of the egg. Think of it as a bunch of columns without tops and bottoms, unable to stand tall, rolling down the slopes of the Acropolis. The male chromosomes do not stay together as a set, are not passed onto each new cell, and have no genetic role. The fathers of these fish are no better off than the males that mate with the Amazon molly. The baby fish produced have only their mother’s genes.

But hybridogenetic fish are better off in one regard: they have elevated levels of genetic diversity. Because their cells contain sets of chromosomes from two or three species, they start out with a lot of genetic variation. This type of virgin birth has fewer drawbacks from a genetic perspective – the all female species are not at risk of inbreeding depression.

I have summarised (in four articles) three unusual forms of reproduction. It is hard to say which is stranger, the hybrid fish that spit out male genes following fertilisation, the female fish that mate only to remind their eggs to develop, or the sharks that managed to reproduce without any sperm at all.

It is interesting to note that the most extreme version of parthenogenesis was found in a species that usually reproduces sexually in a normal fashion. If they had met a male and got some sperm, their eggs would have known what to do with it, and their babies would have had two parents.

Two parents is the normal situation for most fish and sharks. But unlike humans, they can and do cheat, producing daughters without fathers. These species take single parenthood to a whole new level, proving how diverse this thing called life can be.

Previous articles in the sex cell series

Parthenogenesis in the hammerhead shark

Gynogenesis in the Amazon molly

Sperm that crawl instead of swim

I have recently learnt that human sperm don’t swim, they crawl. Who knew?

This actually makes sense, once you think about it, despite all the videos and cartoons that depict sperm swimming. Our internal organs do not have tubes like garden hoses. Passages in the human body are more potential than actual, with tissues on either side touching most of the time.

So it turns out that human sperm, when placed inside a narrow tube, hit one wall or another and then squirm their way along the surface. Worming, not swimming.

But this has me wondering, what do fish sperm do? Obviously, in species with external fertilisation, such as salmon, the sperm have to do quite a bit of swimming. That would happen when the female deposits her eggs and males deposit their sperm directly onto them. Salmon sperm must move through water, without the aid of passageways to guide them to their goal.

But plenty of fish have internal fertilisation as well, and their passages may well permit their sperm to crawl. And I am thinking about the poor crawling sperm inside the fish called the Amazon molly, because they are metaphorically on their knees. I have written about the Amazon molly before in my sex cells series. They are an all female species that nevertheless requires the act of mating for reproduction. The sperm in this case come from another, closely related species. And none of them get to fertilise the egg. This type of reproduction is called gynogenesis.

I had always imagined the poor rejected sperm in the reproductive tract of the Amazon molly as bouncing off the egg after an energetic swimming spree. I would have explained it as two bubbles bumping into each other: they could combine into one big bubble, or bounce away and never join up. Now it seems that the sperm are crawling up to the egg and nudging it, without success.

Of course most sperm are unsuccessful. Even when there is an egg at the end of the passage, and it is of a compatible type (the same species), only one sperm among millions is privileged enough to fertilise any given egg.

As Aldous Huxley wrote:

            A million million spermatozoa,
            All of them alive:
            Out of their cataclysm but one poor Noah
            Dare hope to survive.
            And among that billion minus one
            Might have chanced to be
            Shakespeare, another Newton, a new Donne –
            But the One was Me.

In the case of the Amazon molly, there is not even one. This seems like an incredible waste of sperm for the males who mate with the molly. Why would they do it? Actually, given a choice, males prefer to mate with their own species and have fry of their own. But female fish can also lure the males by releasing hormones that indicate their receptiveness. These wily females are far from virginal, even though they produce virgin born offspring.

Why would evolution produce such an all female species? Every individual produced can give birth to more young, doubling their reproductive potential. There is a catch, however, in the case of sperm dependent species. If they out-compete the sexual species with which they must mate, they would then go extinct themselves. They use the males of another species, but they are also dependent upon those males.

But this doesn’t make things any better for the lowly sperm who crawl all that way to die. On the other hand, they could succeed in fertilising the egg only to have every single one of their genes rejected by the growing embryo. That sneaky scenario can happen, and I can’t decide if it is more kind or more cruel.

But that’s another fish, and another story.

Today is the International Day Against Homophobia. Actually, it is the evening of IDAH and I am trying to understand why anyone would be For Homophobia.

I keep thinking about a suggestion I heard on the radio from a homophobe with a long term view. He thought we should encourage same sex marriage because those couples would remain childless, and homosexuality would be bred out of the human species.

If I could convince everyone that this plan could work, would homophobes join the cause for same sex marriage? As a geneticist I would like to give it a good old tongue in cheek try.

The first observation that must be made is that all homosexuals have both a male and a female parent. We have to explain why most people who are passing on homosexuality are themselves unaffected and clearly heterosexual. Several explanations are possible.

Homosexuality might be a recessive trait, so that you have to have two copies of the particular gene (technically, an allele) to be gay. That means your parents are straight because they have only one copy. In this case it does not affect them because straight is dominant.

Or homosexuality could be co-dominant. I like to think that bi-sexuality is co-dominant, all balanced and binary. Instead of just straight vs. gay, there would be three phenotypes. You might have straight, bent and more bent. Or likes boys, likes girls, likes both.

We could have variable expression of the trait, with different outcomes depending on gender. A gene that makes a girl like girls might make a boy like girls even more than usual. This would mean that the lesbian gene is spread largely by men who love women a whole lot. A gay gene would then be causing rampant heterosexuality.

But the most interesting situation would be if homosexuality were caused by a dominant allele. This would give us the best chance to breed it out. The problem with this hypothesis is that when the allele is dominant, the parents of affected individuals are always affected too. All homosexuals would have at least one homosexual parent, and that is apparently not the case.

The only way the gay gene could be dominant is with incomplete penetrance. Stop laughing. I know that sounds funny, but ironically, it is the only thing I have said so far that could actually be true.

Incomplete penetrance is a real genetic term that provides a way to wriggle out of the dominance dilemma. Under incomplete penetrance, some people who carry the dominant allele are nevertheless functioning heterosexuals. They are so deep in the closet that they don’t even know it themselves.

The best scenario for reducing the frequency of a trait is for it to be dominant, and for its expression to result in no offspring production. Amazingly, these conditions can be met for homosexuality. All that has to happen is for every homosexual to accept themselves early, marry young, and stay faithful to their partner. True love is the answer.

Incomplete penetrance, however, is still a problem. (It always is, somehow, especially if you have to teach it to teenagers). It could mean that potential homosexuals are indulging in heterosexual behaviour. It is possible that the environment could play a role, for example, when society makes it easier to bring home someone of the opposite sex.
We need to encourage more people to express their latent homosexuality. It would help the cause if we embrace same sex marriage, celebrate true love in all its forms, and make homosexuality super cool.

If that makes you feel squeamish, just remember that you could have the last laugh. In the long term, it could reduce the incidence of homosexuality. In the short term, it will just reduce sorrow and suicide and the need for birth control.

By the time I publish this it will no longer be International Day Against Homophobia. Is this the end of the rainbow, or the beginning?

We have had an exciting birth in our household. A stick insect hatched! My husband Geoff is a teacher who has been lucky enough to participate in a program with the Melbourne Zoo to rescue an endangered species of stick insect. Although we did not get to observe it hatching, a video of one of them emerging from its egg is a family favourite.

The Lord Howe Stick Insects were thought to be extinct, before a few individuals were found on Ball’s Pyramid, a remote rocky islet 23 km from Lord Howe. The discovery of this tiny isolated population about 11 years ago is a story of bravery, tenacity and intuition by the researchers involved. Stick insects, or phasmids, are usually quite cryptic , and many species are common on the Australian mainland. True to their names, they usually mimic the vegetation on which they rely, and surprisingly, they make great pets. Requiring only native vegetation and a spray of water, they are easy to care for and are good for impressing your friends. Geoff and I have kept and raised phasmids for years.

But the Lord Howe Stick Insects, which start out bright green and small, grow to an enormous size and become a deep glossy black. The adults are so large and striking that they have earned the name Land Lobsters.

A shipwreck on Lord Howe Island in 1918 had the unfortunate consequence of introducing black rats to the island, with devastating consequences. Several species of birds and the stick insect succumbed to the appetite of the rats. Within a few years these giant land lobsters were thought to be extinct.

Consequently, the discovery of some Lord Howe Stick Insects living on a small shrub clinging to the cliffs on Ball’s Pyramid was a significant find. Because they hide in crevices during the day, the researchers had to make a hazardous landing at night and climb in the dark to collect a few individuals.

Two of those found their way to the Melbourne Zoo where they were named Adam and Eve. Their offspring now form a captive breeding colony. As part of their program, the zoo invited Victorian schools to apply for chance to raise small colonies of their own. Geoff, as the Science Coordinator at Tallangatta Secondary College, put in an expression of interest and was successful. He attended a training session at the zoo in March where he received a container of eggs, shrubs for food, and a purpose built enclosure.

On Sunday morning he went in to school to check on his charges, and one of the eggs had hatched. It was cold in the classroom, so he brought the baby stick home along with its enclosure. We cranked up the heater in the lounge room and the small bright green insect was gently transferred to its new home. Here is a video of its first steps:

During the day, the newborn stick insect hung about cryptically and ate part of a leaf. I can’t tell you how excited we were by this, and how many times we peered through the glass to see if it had moved. The temperature was checked, the heater moved, and water was gently sprayed to keep up the humidity. Like new parents, we even enjoyed watching the little thing sleep.

Now the baby Lord Howe Stick Insect is back at school, where we hope it will soon be joined by others. Apparently, the adults form pairs and are so devoted to one another that they sleep curled up together. I look forward to watching this behaviour.

Mostly, I am just thrilled to be playing a small part in bringing the Land Lobster back to Lord Howe Island. Of course, the rats will have to be removed before they can be reintroduced to their original habitat, but that is another story.

I hope the students at Tallangatta and elsewhere appreciate how precious it is to have a role in bringing an endangered species back from the brink.

In my first year biology lectures I have a ritual that my students seem to enjoy. I put a quote of the day up on the overhead projector; something for the students to reflect on while they find their seats and I warm up the lectern. Although I choose quotes relevant to the topic de jour, I do not usually comment on them.

But yesterday, as I was preparing to deliver a lecture on the evidence for evolution, I looked at the day’s quote and found myself embarking on an involuntary rant. Typically, my students remembered the rant and forgot the lecture. Worryingly, they may not have been able to tell the difference. Hopefully, it did them no harm. You can be the judge, as I replicate my rant here.

“There are in fact two things, science and opinion; the former begets knowledge, the latter ignorance.” — Hippocrates

Hippocrates’ quote about science and opinion reminded me why I did not watch the recent TV show called I can change your mind about climate change, although I have heard a lot about it.

I cannot bear to watch or read anything that labels the proponents of these debates as sceptics and believers. The misuse of these words creates enough confusion to overpower any substantive points that might be made in the process.
The way these words – sceptics and believers – are used in discussing climate change, just drives me nuts. As Hippocrates says, one is science and the other opinion, but when these words are linked to climate change, their meaning is opposite to their definitions. This is sneaky, underhanded obfuscation.

Sceptics, as portrayed in the media circus, are completely mislabelled. Those who deny actual evidence cannot be called sceptics. They begin by believing in the rightness of their cause, and then cherry pick their facts. No true sceptic would develop an argument based on bias alone.
Scientists are the true sceptics. They begin with doubt, rather than beginning with belief. They ask themselves, “What kind of data could I collect that would prove to me that an idea I think is right is actually wrong?”

Scientists ask rigorous questions, test assumptions and scrutinise each other’s logic. Yet when 97% of scientists agree that climate change is caused by human activities, they are labelled “believers”.

This is a deeply misleading word for the scientists involved, and it is offensive to true believers as well. I am aware that teaching evolution often causes conflict for students whose families think this branch of biology is opposed to a belief in God, but I do not expect my students to deny themselves a spiritual connection to the universe. Doing our best to love the earth, each other or ourselves does not preclude a sensible approach to knowledge.

Indeed, true scepticism is healthy. It allows a person to begin from doubt and move toward something. Scepticism is about moving toward certainty by testing one’s own assumptions. It is about knowledge; the realm of the mind.

True belief can also be healthy. It allows a person to begin from a private experience or emotion and move toward the unknown. Belief often involves a leap of faith because evidence is not available. It is about transcendence; the realm of the spirit.

Climate change deniers are neither sceptics nor believers. They do not believe in anything, other than their own opinions. Because they try to argue about the evidence, they pretend to be sceptics, but they are not. Their scholarship is insufficient, their doubt is selective, and their arguments are flawed.

Saying that facts are not true does not make you a sceptic. The outcome of research is not a matter of opinion. Deniers of scientific evidence are not sceptics, they merely sow the seeds of doubt. Scientists are not people who believe, they simply seek to know. They want to remove doubt from the equation.

I am happy to engage in scientific debate. I am even happy to talk about personal belief systems. But I am not happy to continue to see words twisted and labels misused to muddy the debate about climate change, by people who are neither sceptics nor believers.

Yesterday morning it was part of my job to tell my students that evolution is a fact.There are mountains of evidence for it, some of which I summarised. But I had to explain that evolution is also a theory, because it is understood using theoretical constructs and paradigms that are constantly tested.

Over 150 years since Darwin, scientists continue to learn about evolution by debunking every new idea about the details.

Now, that’s scepticism for you.

As good news stories goes, this is one of the best. Mountain pygmy possums are one of the most critically endangered species in Australia, and possibly the cutest. The recent genetic rescue of the Mt. Buller population has been achieved through translocation – releasing wild caught males from another population to introduce genetic diversity.

Last week this story made the news and was featured on the TV show Catalyst.

Unlike other pygmy possums, which live in forests and nest in the trees, the mountain pygmy possum lives under boulder fields high in the alps. Mountain pygmy possums do not like to emerge from their rocky enclaves, and will only do so voluntarily under dense shrub cover.

Ski field developments on Mt. Buller meant their natural habitat was highly fragmented by roads and ski runs which had been cleared of rocks. This was done before we knew that the possums were there: the population on Mt. Buller was not discovered until about 1996. Male possums were forced to cross roads and open ski runs to find mates, which exposed them to predation. With only a few males surviving each year, the Mt. Buller population became inbred and eventually succumbed to a severe genetic decline.

Captive breeding was considered the best way to help the species recover. But breeding up enough animals to release into the wild proved difficult in practice, so in 2010 a few male possums from the healthy population at Mt. Hotham were introduced to Mt. Buller and two hybrid offspring were produced, proving that this strategy might be successful.
In September 2011, in time for the breeding season, six males from Mt. Hotham were released onto Mt. Buller, and when the young possums were trapped and tested for genetic markers, half of them were found to be hybrids.

In addition, the hybrid juveniles were 15% heavier at the end of summer than the possums whose parents were both from Mt. Buller. This extra weight may be critical to survival for a species that need to put on enough weight over summer to allow them to sleep through the winter.

Translocation, or the release of individuals from a distant location for the purpose of introducing new genes into a population, has not been tried before in Australia. Some scientists think that the mixing of genotypes in this way reduces the distinct characteristics of the populations involved, and should therefore be avoided. But when a population is clearly in decline in both fitness and numbers, there may be no other choice.

Well done to the brave researchers who have given the mountain pygmy possums of Mt. Buller another chance.

In a recent post, I was hopeful that a meeting in Guam would take steps to protect the tuna fishery in the Pacific. Unfortunately, the Western and Central Pacific Fisheries Commission ignored the advice of their own scientific committee and chose to do nothing at all. The situation is complex — politically, socially and economically.

Some of the Pacific island states who belong to this organisation rely on the tuna fishery for up to half of their gross domestic production. So it is understandable, on the one hand, that they do not want to limit their ability to benefit from this renewable resource. On the other hand, the science is not in the least ambiguous. Without effective management, this fishery is not sustainable. Why would any nation put their future at risk by not addressing the situation?

What is going on? As a scientist, I feel concerned when the best available advice is ignored. At the same time, the public seems to feel betrayed by science, which has for many years been making our lives easier. Why now, does science want to make our lives hard?

In the twentieth century, science seemed to have the solution to all our problems. Now in the twenty-first century, science is telling people that we need to change our behaviour and live more gently on the earth. Ironically, the two are not unlinked.

In the case of ocean fishing, it was technology that allowed us to harvest tuna so efficiently that some species have now became threatened. Science made us so successful that we need to regulate the fishery if we want to continue eating ocean caught tuna into the future.

Similarly, river regulation in the Murray Darling Basin allowed us to turn parts of a dry continent into a productive food basket, but at what cost? Now we need people to reduce their reliance on water so we can ensure the health of the environment. Protecting the river will be good for the economy and future of our communities, but many do not want to have to change their behaviour; they are ready to fight the plan.

My point is that science cannot save us from ourselves. And I am deeply surprised when scientists are accused of having hidden agendas and political motivations. Scientists, by and large, avoid those pitfalls both through training and temperament. What scientists do is think hard, test ideas against the facts, and use logic to make conclusions and predictions.
We only speak out when we are fairly certain of our conclusions, and since we tend to be conflict averse, we do not make tough recommendations unless we feel we have no choice.

The truth is that nobody wants the tuna fishery to fail, the climate to change or the rivers to run dry. But to prevent these possible futures, we need people, politicians and businesses to listen to wise counsel.

Some might say that scientists need to learn how to become politically astute, economically relevant or socially adept. I do not think we could do so and continue to do our jobs properly. A certain amount of introspection, a degree of separation from the outcome of our enquiries, and a big dash of pedantic obsession is required to ask the right questions, gather useful data and develop robust models.

But what can we do when the solutions to global problems do not exist in the realm of science or technology? When solutions require individuals, businesses and governments to change their behaviour, scientists are powerless. The flip side of this conundrum is that the power is in the hands of people. Individuals can convince governments and sway businesses to change. The question is, will they choose to do so if they do not believe in science?

I am sorry for the bigeye tuna, whose future is at risk because 500 delegates could not agree on a better way to manage the tuna fishery. But I am even more sorry that this pattern of ignoring the best that science has to offer will be repeated again in other scenarios.

I recently wrote about virgin birth in hammerhead sharks where I tried to explain parthenogenesis, a process at the level of the sex cells which allows females to produce offspring without the benefit of a male. It only occurs in sharks when they are unable to find a mate, but parthenogenesis comes in many forms.

Sperm dependent parthenogenesis requires the stimulus of the sperm to remind the egg to turn into an embryo. This type of parthenogenesis occurs in a small fish known as the Amazon molly, because the species is entirely female. They were named after an ancient, possibly mythical society of female warriors. No men were allowed to join Amazonian society, although men were sometimes kept as slaves, and for sex.

Similarly, the little Amazon molly mates with males of other closely related species, but since the sperm is not allowed to fuse with their eggs, they keep their bloodline pure. Paradoxically, this creates a situation where they produce virgin born offspring without technically being virgins themselves.

The male fish that mate with the Amazon molly are wasting their time. These males, who belong to other molly species, put effort into sperm production and the act of courtship without the desired result. None of their genes contribute to the next generation.

It is interesting to note that the egg cells of the Amazon molly have not gone through the process of meiosis. That is to say, their chromosomes have not swapped alleles and distributed themselves into separate cells. What this means is that the all female offspring contain exactly the same genes as their mothers. This differs from the case of the hammerhead shark, where genetic diversity is lost during parthenogenesis.

Keeping all the genetic diversity from one generation to the next may go some way to explain the survival of this asexual species, scientists are baffled that the Amazon molly has been successful for so long. Theoretically, this species should have gone extinct thousands of generations ago.

Some scientists think that the small portions of male chromosomes are occasionally incorporated into the eggs to create enough genetic diversity to allow the species to thrive.
Sex cells will always find a way to swap a few alleles, even if they have to get them from another species altogether.

Sex cells that live inside sexually active virgin fish are particularly creative.

I was listening to Triple J on Tuesday afternoon when comedian David O’Doherty shared what he called a show stopping fact: female hammerhead sharks can produce baby hammerhead sharks without the benefit of a male. A lively discussion ensued, at the end of which the interviewer, known mysteriously as “The Doctor”, attempted to enlighten us by saying, “It’s called parthenogenesis."

Even the Doctor stumbled on that last word. But I am here to tell you that Parthenogenesisis a lovely word, from the Greek. Partheno means virgin and genesis is about birth, or beginnings. To remember it, think of the Parthenon being generated from the barren soil of the Acropolis in Athens.

As you think of the Parthenon, imagine that the columns are chromosomes: long and grooved with an ornate base and top. The columns hold up the whole structure of the temple. In a similar way, chromosomes (which are homes for our DNA), provide structure to this thing called life.

The truth is that parthenogenesis itself comes in several forms, all having to do with how the chromosomes arrive. Whether or not they are complete depends upon the nature of their journey from a previous cell. So I had to look into it, to learn what happened in the hammerhead shark.

I was delighted to discover that the baby hammerhead shark was born at the Henry Doorly Zoo in Omaha, Nebraska, because I grew up in Nebraska and have visited the zoo many times.

There were three female sharks on display, all of which had been collected as babies and had never met a male shark. Nevertheless, since female sharks can store sperm, the scientists had to rule out the possibility of an insemination event.

DNA tests revealed that the baby shark contained only it’s mothers DNA. Not only were there no new genes which would have pointed to a potential father, there were actually fewer genes in the baby than in the mother. More precisely, there were fewer forms of each gene.

Genes come in various versions, consisting of short stretches of DNA with slight variations that we call alleles. Think of all these little eels, twined around the columns in the Parthenon. Chromosomes are simply swarming with alleles.

When the sex cell of the shark went through a process called meiosis, every column swapped some eels with another column, and then distributed themselves under four new parthenons. Four cells with different sets of chromosomes, each carrying different alleles were produced.

One of those cells was the egg, and the other three were her smaller sisters, or polar bodies. Like bridesmaids at a wedding, their job is to support and care for the bride. In the hammerhead shark which had waited too long for a sperm, the egg decided to fuse with a sister polar body, and the baby embryo was formed.

Unfortunately, in this scenario, some alleles got swapped away. Unique eels were left behind in the unchosen bridesmaids. This means that the baby shark lost genetic diversity, and if this went on for generations, evolutionary potential would be lost.

The sharks know this. Even the baby who had never met a male would prefer to join her sex cells with another shark than be forced to join her own. Creating and maintaining diversity is the whole reason for sex, even though many animals and plants are able to do without it at times. Having the ability to produce a baby shark without a male may mean that an isolated group of sharks can survive long enough to find a mate.

Other sharks seem to have this ability. An Aquarium in Detroit stopped throwing away the eggs laid by their spotted bamboo sharks, which they thought were sterile, once they heard about the virgin born hammerhead. Lo and behold, the bamboo shark eggs hatched even though there were no males in the tank.

During the interview on Triple J, the Doctor and Dave were worried that men might become redundant. In the short term they were worried about themselves, about whether human females could find men unnecessary. In the longer term they may have wondered that evolution might choose a simpler paradigm, with many species deciding to produce offspring without the need for sperm. There is good news on both counts.

Parthenogenesis has never been observed in a mammal. This is not to say that it may not be discovered in some isolated mammal in the future, but the human species is not at risk of virgin births on a grand scale. And in the longer term, the need for genetic diversity is so strong that sex cells and the need to combine them from unrelated individuals will never go out of fashion.

Swapping alleles is too beneficial for any species to give it up without a very good reason.

Fifty percent of the world’s tuna is caught in the Western and Central Pacific region. Today, a meeting in Guam will determine if this fishery will become more sustainable or continue to harm endangered species. This has been highlighted on this morning’s radio.

Three different species of tuna are caught in the region: yellow tuna, skipjack tuna and big eye tuna. The challenge is to ensure that overfishing does not occur, and to control by-catch. By-catch are the species that are killed as a side effect of fishing for the target species. Ironically, big eye tuna, which are the most threatened of these three species, often die as by-catch when fishing boats are targeting skipjack tuna.

Dolphins, whales and sharks are common by-catch victims of the tuna industry. Whale sharks often swim above schools of tuna and are used by captains to identify likely fishing spots. This practice of targeting whale sharks leads to the death of the whale sharks. This is one issue under discussion at the meeting in Guam: can we ban the targeting of endangered species as part of the tuna fishery?

I have argued before that we need to eat less fish. But since many of us continue to rely on the protein provided by fish such as tuna, we can make a difference by changing the way we fish. Using more appropriate gear, altering standard methods of targeting fish and limiting by-catch are all important steps toward sustainability of the industry.

Let’s hope that the Western and Central Pacific Fisheries Commission is able to convince the 25 countries involved to improve fishing practices in our region.

A recent paper in Nature Geoscience has proposed that when the first simple plants moved onto land, they fundamentally changed the atmosphere by accelerating the weathering of rocks.

The time: the late Ordovician, between 444 and 488 million years ago (but who is counting?). The place: rocks and soil on land, a place previously devoid of plant life. The main characters: moss and other non-vascular plants. Although plants were common in the oceans, the first land plants evolved at this time, spreading across the land and breaking down the chemical components of rocks. The absorption of atmospheric carbon by the new land plants may have chilled the planet sufficiently to induce glaciations.

The British scientists who make this claim considered the geological evidence for climate change at the time and found that it was insufficient to explain the reduction in atmospheric carbon dioxide during that time period. They then conducted laboratory experiments that tested the ability of mosses to enhance chemical weathering. Incubating granite or andesite substrates with moss significantly increased the release of elements such as Calcium, Iron, Magnesium and Phosporus. The release of phosphorus increased productivity in the oceans, where it is the ultimate limiting nutrient. This may have triggered anoxia in some parts of the oceanic environments and created high carbon loads which were deposited as black shales.

Ironically, the environmental changes brought about by the first land plants may have contributed to a mass extinction of marine plants and animals at the end of the Ordovician. That is to say, the new land plants (think moss) may have caused the death of their ancestors (such as algae) in the oceans. I am sure this is not the first time that children have altered conditions such that their parents struggle to cope.

I wonder where else this happens, in life?