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Tuna or not tuna? The real cost of taking a fish out of water

The Commission for the Conservation of Southern Bluefin Tuna is meeting today to discuss raising Australia’s tuna fishing quota. The tuna industry is expected to ask for a 30% rise in Australia’s allocated…

Southern bluefin tuna are critically endangered, but the fishing industry wants to catch more. AAP

The Commission for the Conservation of Southern Bluefin Tuna is meeting today to discuss raising Australia’s tuna fishing quota.

The tuna industry is expected to ask for a 30% rise in Australia’s allocated fishing rights for the critically endangered species.

But conservationists say stocks are still too low for fishing to resume at this level, and the science of conservation is being ignored.

But focusing solely on tuna ignores the wider threat to the environment posed by fishing in the first place.

We need to reassess our approach to commercial fishing as a whole if we are to avoid a massive environmental fallout.

Bluefin tuna are a sought-after commodity. mttsndrs

We need to eat less fish

It will come as a surprise to some that eating fish is bad for the environment. In the past, fish was seen as a healthy and sustainable food option with few ethical implications.

But we know now that fishing fleets are completely dependent on fossil fuels, and have to travel longer and longer distances to find fish in commercial quantities. We also know seafood stocks are crashing at an alarming rate.

The methods we use to improve catch rates harm habitats and kill other species we never meant to eat in the first place.

Unfortunately, farming fish does not solve these problems.

The best solution to this growing problem is to eat only those fish you know to be harvested sustainably. Unfortunately, you will soon discover that this means eating a lot less fish.

The way we catch and consume fish is completely unsustainable. AAP

Counting the carbon cost

Fishing used to be an idyllic pastime that involved sitting on the riverbank or floating in a canoe. But the fish that end up on your plate today are caught in large quantities far from shore using boats that use up huge amounts of energy.

Fishing fleets account for 1.2% of global oil consumption. That is equivalent to the consumption of an industrial nation.

Small fish like anchovy and herring, which travel in schools, can be captured for 50 litres of oil per tonne, but shrimp, tuna, swordfish, sole and flounder can use up to 2000 litres of oil per ton.

When you add refrigeration and transport to get it to the consumer, the carbon costs of fish are considerable.

Extinction is forever

When fish stocks fail, they do so quickly and catastrophically.

When cod stocks in the North Atlantic collapsed and the fishery was closed in the 1990s, more than 40,000 people lost their jobs and many communities that relied on the industry still have not recovered.

Despite the apparent vastness of the oceans, it has become clear that fishing can have a significant impact on fish populations.

Fish aggregation devices find fish that would otherwise be protected. AAP

Improvements in fishing technology have allowed us to find populations that would have been protected in the past. Electronic fish finders, larger boats, and high tech netting systems let us continue to find fish even when the stocks are low.

Deep-sea fish are often slow growing and individual fish can be very old. Orange roughy might be 150 years old by the time they are dragged to the surface for our dinner.

Every time we eat a large fish we remove its potential to contribute to the next generation.

Obviously, there are some fish that just should not be on the menu.

The consequences of global over-fishing are clear. Many fish species are close to extinction, and some are not are no longer viable to commercial fisheries.

Fishing hurts the whole ecosystem

Animals inadvertently caught by fishing activity are referred to as by-catch.

Ocean fishing practices kill large numbers of turtles, dolphins, squid and seabirds. By-catch can also include the juvenile fish of the species being targeted, removing the next generation and killing the future of the fishery.

Shrimp trawling can have by-catch ratios as high as 20:1 – for every tonne of shrimp collected, 20 tonnes of other species are destroyed.

By-catch is a serious problem for the fishing industry. ASOC pictures

Some fishing practices harm the habitat directly. Bottom trawling involves dragging a net along the ocean floor, removing seaweed beds, shattering coral, and disturbing otherwise productive sediments. These are the habitats fish rely on for survival.

A global study from 2006 says that the reduction in ocean biodiversity caused by human activities is likely to result in the destruction of all our current seafood fisheries by the year 2050 if we don’t take drastic action.

I know I would prefer a future world in which fish still swim in the sea.

Farming isn’t the solution

It would seem that one answer to the destruction of wild fish stocks and habitats is fish farming, but aquaculture is not the panacea one might hope.

Fish farms are carbon intensive and require vast amounts of fishmeal. Fishmeal is made from other fish species that are caught by unsustainable methods. It takes two kilos of fish and squid meal to produce a kilo of farmed shrimp.

What can we do?

When governments are serious about protecting fish stocks they make a huge difference.

Regulations that limit the acceptable level of by-catch can drive the production of innovative and effective technology and practices.

Marine reserves established to protect ocean ecosystems have been more effective than even the scientists expected.

As for individuals, any change in consumer demand has a big impact on which fish are targeted.

Community awareness of fishing practices is growing. AAP

You can personally change the fishing industry by not buying fish that are collected unsustainably. Educate yourself about which fish are good to eat and which ones to avoid by using internet sites such as Good Fish Bad Fish.

The environmental damage that occurs in the ocean is invisible to the average person. The consequences of over-fishing will not be apparent until it is too late.

One small thing we can do for all the species that depend on a healthy ocean (and we are one of those!) is to ask questions about the fish we are eating.

Are they older than your grandmother?

Did catching them kill tonnes of other innocent species?

How much carbon was used to get it onto your plate?

Or, to keep it simple, we can just stop eating fish.

Join the conversation

11 Comments sorted by

  1. Byron Smith
    Byron Smith is a Friend of The Conversation.

    PhD candidate in Christian Ethics at University of Edinburgh

    Thanks! This is an excellent summary of an important issue. I particularly appreciated learning about the carbon footprint of fisheries, which was not an issue I was particularly aware of before.

    1. Byron Smith
      Byron Smith is a Friend of The Conversation.

      PhD candidate in Christian Ethics at University of Edinburgh

      In reply to Byron Smith

      Oops, I meant to add that the carbon footprint of industrial fishing is of course linked to two more of the great threats facing the world's marine ecosystems: ocean acidification and ocean warming (which shifts species ranges, increases stratification and is linked to coral bleaching). I had no idea that industrial fishing contributed so much to these issues directly.

  2. Stephen Prowse

    Research Advisor at Wound CRC

    This is an interesting and important article except for the last line. Seafood is an important part of the diet of many people so to stop eating fish is not realistic. Perhaps we should be more strongly supporting research to improve sustainable wild harvesting, reduce the impact of aquaculture and identify and promote the benefits of marine reserves. It would also be useful to know the basis for the anticipated request for a 30% increase in tuna harvesting.

    1. Byron Smith
      Byron Smith is a Friend of The Conversation.

      PhD candidate in Christian Ethics at University of Edinburgh

      In reply to Stephen Prowse

      Stephen - Are you aware of how severe this problem is? We are likely within decades of seeing all commercially viable stocks collapse. There won't be many people eating fish once we reach that point, so we need to cut back now in order to avoid it.

      I agree with your other suggestions, but think that they will likely be insufficient on their own.

      I would also like to know the basis for the requested increase in tuna catch.

    2. Jane Rawson

      Editor, Energy & Environment at The Conversation

      In reply to Stephen Prowse

      Stephen and Byron, here's what the ABC quoted the fishing industry as saying:
      Australian Tuna Association chief executive Brian Jeffriess says the fishing industry is only looking to recover the 25 per cent drop in quota it lost in 2009.
      He says a final scientific report will show the quota increase is sustainable.
      "What it says is that you can set the quota much, much higher than we're asking for," Mr Jeffriess said.
      "All we're asking for is the quota that we lost in 2009 when the quota was cut."

      You can see the full story here:

    3. Byron Smith
      Byron Smith is a Friend of The Conversation.

      PhD candidate in Christian Ethics at University of Edinburgh

      In reply to Jane Rawson


      Bluefin tuna numbers have dropped by something like 95% in the last few decades. Any increase in quotas at this stage seems shortsighted. I realise that southern bluefin tuna are distinct from other varieties of bluefin (and their situation is not quite as critical), but this is not a sustainable industry at present levels and so any attempt to "create more jobs" by reflating Australia's quota is very likely to be short-lived.

    4. Susan Lawler

      Head of Department, Department of Environmental Management & Ecology at La Trobe University

      In reply to Stephen Prowse

      Obviously we can understand the science but still object to having to change our behaviour. This is human nature. But it is completely realistic to not eat fish. I have personally not eaten fish for 32 years (so far). I would prefer to live in a world where people can choose to eat fish, but given our current fishing practices, that choice will be removed from the next generation. Eating less fish now may mean that there will be some fish for our children to eat later on.

  3. Annalisa Roger

    Founder of

    We have to get this article out to as many people as possible!

    I see it like this...we have been politically correct about people's cultures and diets and customs for decades...that is sensitive and ideal, but now we are out of time! ... and scientists KNOW and SEE the evidence that we are out of time to just keep "thinking" about things, etc.

    I LOVE eating fish !!!! I would eat it everyday if I thought I could get away with it. I know it is good for me and my children to eat fish. The truth is NONE of us can ever eat fish again if we don't SAVE OUR PLANET starting with our ocean!!! Fish dependent cultures have the most interest in the sustainability of wild fish! They need to lead the movement! Either we choose to stop depleting BEFORE extinction, or the decision will be made for us AFTER extinction...and then no one will be eating fish, regardless of culture. Extinction is forever! Cultural diversity is beautiful too - preserving resources preserves culture.

    1. Byron Smith
      Byron Smith is a Friend of The Conversation.

      PhD candidate in Christian Ethics at University of Edinburgh

      In reply to Annalisa Roger

      Functional extinction can occur well before actual extinction. Commercial fisheries collapse prior to the total elimination of an entire species. Both are threats, though the former is currently the proximate outcome, and is the one that has the most widespread and immediate human impacts.

      So I guess I'm raising a question of messaging: which danger ought to be given more attention?

    2. Susan Lawler

      Head of Department, Department of Environmental Management & Ecology at La Trobe University

      In reply to Byron Smith

      Bryron, you raise an excellent point. Functional extinction is what we are going to notice. When fisheries collapse, people lose their livelihoods and communities are destroyed. The fish species that is no longer commercially viable will get a chance to recover, but the damage to human enterprise has been done.

      We need to change the conversation from one about quotas to one about sustainability. What do current fishing practices do to future fishers and their families?

  4. Pandoy Filipino


    In my line of work, I have had the opportunity to access four SPC logsheets from two purse seiners. For the information of people not familiar with this, SPC logsheets are reports generated by the fishing vessel’s officer and are counter-checked by the fisheries observer onboard. The fisheries observer is a representative of the government who acts as an auditor as well as an enforcer to ensure that fishing activities are executed and documented according to the set “rules”. Please pardon the way…

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