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Bycatch the real concern as super trawler heads for Australia

Concerns about licensing a foreign super trawler to fish our southern seas have centred on the negative effect on fish stocks. These fears are largely unfounded. The real concern is for Australian mammals…

It’s not the fish we should worry about, but the other creatures the “super trawler” will catch. Charles Van den Broek

Concerns about licensing a foreign super trawler to fish our southern seas have centred on the negative effect on fish stocks. These fears are largely unfounded. The real concern is for Australian mammals which will inevitably meet their demise in some numbers because of the mid-water trawl method of fishing.

Catch likely to be sustainable

There is little doubt that the quota of 18,000 tonnes of small pelagics, issued by the Commonwealth to the MV Margiris to be taken off Australia’s south coast, will not lead to depletion of fish stocks. This quota is only half of the total allowable catch (TAC) currently set for the fishery.

The catch of jack mackerel in the Commonwealth managed Small Pelagic Fishery (SPF) has been very small because fishing has been unprofitable. Only 156 tonnes of jack mackerel was taken in 2009-2010. The total catch of the several species in the SPF was only 2,482 tonnes. The low catches will have enabled the recovery of stocks after very heavy fishing in the 1980s and 1990s.

Commonwealth of Australia

Having said that, the fishery is due for an update to its harvest strategy based on a biomass assessment, something that has not been done for five years. It is important to review stocks so that TACs can be confidently declared for the longer term. A biomass assessment will be particularly useful for the slow growing, long-lived and slow to breed jack mackerel (east), whose TAC has been recently raised from 4,600 to 10,000 tonnes – and of redbait (west), listed as “uncertain” in status and with a TAC of 5,000 tonnes.

Problems with the mid-water trawl

The small fish are the regular diet of the Australian fur seal (Arctocephalus pusillus doriferus). The fish in the net being trawled behind the MV Margiris will be very enticing for the seals; but for many it will be their last dive.

Monitoring has shown that seals enter the body of a trawl in half of all shots; and that about one in every five interacting seals will drown. Trawlers provide a seal exclusion device (SED) in their nets. But many seals fail to find the mouth of the net or the hole provided by the SED.

Underwater cameras have shown that more seals meet their demise in mid-water trawl nets than was previously thought. This is because the dead ones roll out of the net unseen during hauling. The seven independent scientists who recently gave the SPF a clean bill of health, augmented their conclusions as follows: “… measures … will be required to manage the ongoing risk of marine mammal interactions and capture”.

Seals get inside trawler nets to eat fish. Some can’t get out. Lyle and Wilcox

Research recommends the top-opening SED, yet the main vessel that has been fishing uses a bottom-opening device. There is considerable scope to further refine the orientation, size and scope of SEDs. But crucial trials to find optimum devices have not taken place, due to lack of funding and very low activity in the mid-water trawl fishery.

MV Margiris will continually encounter seals. Several dolphin and whale species might also invade trawl nets. And there are two bird species listed as “vulnerable” under Commonwealth legislation (shy albatross and black-browed albatross) that may suffer mortality but at low rates.

Who cares about seals?

The NSW Government lists the Australian fur seal as “vulnerable”. It says that the seal is directly threatened by fishing operations and that fishing may limit the availability of prey. And it says the species is also threatened by entanglement or ingestion of plastic debris increasingly discarded from boats or washed out to sea.

The depleted population of Australian fur-seals resulting from commercial sealing has increased the species' vulnerability to other threats. For example small colonies on islands are susceptible to stochastic events such as oil spills.

The range of the Australian fur seal overlaps the Commonwealth’s SPF, but the Commonwealth does not share the concerns of the NSW government and has not listed the Australian fur seal as endangered under the Environment Protection and Biodiversity Conservation Act 1999. It is an offence to kill, injure, take, trade, keep, or move Australian fur-seals in Commonwealth waters. But it can be done with a permit, and presumably a permit will be issued.

Environment Minister Burke is thus toothless when it comes to stopping fishing by the MV Margiris on the grounds of threats to listed species unless he invokes the threat to listed albatross, which is very unlikely.

The Commonwealth may have had some authority in demanding that the MV Margiris deploys nets configured to minimise seal mortality. But such action cannot be taken because effective SEDs don’t exist. Monitoring and observing the super trawler is all very well, but the Commonwealth won’t be able to stop the drowning of Australian fur-seals.

Instead of feeding small fish to tuna then eating the tuna, why not eat the small fish? norobodo/Flickr

Culinary switch recommended

Most of the catch of small pelagics and sardines in Australian waters goes to fatten juvenile southern bluefin tuna (SBT) caught and penned in South Australian waters. Under the Commonwealth’s own assessment, the tuna is overfished and subject to overfishing. Moreover, the species is listed as “threatened” under the Victorian Flora and Fauna Guarantee Act 1988, and “endangered” under the New South Wales Fisheries Management Act 1994. The World Conservation Union lists this tuna as “critically endangered”. Though it lists the SBT as “conservation dependent”, the Commonwealth continues to issue SBT quota because of the business is so lucrative.

Using small pelagics to fatten tuna is inefficient: the conversion ratio is very low. Every tonne of farmed tuna requires between 10 and 20 tonnes of feed. The feed is Australian-caught small pelagics, Australian sardines or imports.

This inefficiency is grounds to suggest we stop eating tuna, and start eating small pelagics and sardines ourselves. These highly nutritious fish – delicious when grilled Portuguese style – would make an important contribution to healthy diets and at the same time could relieve pressure on overfished shark and snapper. Before we make such a culinary switch, however, we should prove that trawling is not killing animals and birds.

Meanwhile, it looks as though we will have to grit our teeth knowing that Australian fur-seals will likely be drowning in numbers while the MV Margiris is trawling our waters.

bJORk(D)mAN/Flickr

Join the conversation

14 Comments sorted by

  1. Ian Ritchie

    mad

    I fail too see what earthly good comes from allowing this so-called 'super trawler' to operate at all. Where is the benefit to Australia, the Australian people, Australian sea life and the environment which includes the mammals and other sea creatures alluded to in the article.
    What are they doing here anyway? Don't they have any fish in their part of the world?
    Piss them off.
    They can fish off their own bloody coastline - if they haven't fished it to the brink.
    I can live without the catch that will be (presumably) be canned in Europe and shipped back to supermarkets world wide as a 'value added' product.
    No. No. No. Go away.

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    1. Colin Hunt

      Honorary Fellow in Economics at University of Queensland

      In reply to Paul Wittwer

      Paul, European subsidies for fishing are of course deplorable. However the immediate issue is not who is fishing but whether the level of fishing will be sustainable. In the articles you point to, Wadsley addresses the problem of level of fishing and spawning biomass of jack mackerel; I called for an updated assessment of its biomass in the article. And Nevill says fish less than 25% of biomass: in fact SPF quotas meet this criterion (unlike many other Commonwealth fisheries). Neville also advocates an ecosystem approach - and the impact on the ecosystem is what my article is actually about.

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  2. Wade Macdonald

    Technician

    This article does not address the public admission by Seafood Tasmania that it seeks to increase this quota down the track. The potential for localised depletion on stocks if this boat doesn't 'spread the load' of it's operations is also of major concern.

    I haven't seen one credible report that shows this boat has fished sustainably anywhere before either.

    I don't like calling for unjustified bans before sound management but this smells of vested stupidity and if the majority of Aussies don't want it here then it should go.

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    1. Colin Hunt

      Honorary Fellow in Economics at University of Queensland

      In reply to Wade Macdonald

      Wade, You raise several pertinent points. Any increase in future quota would come after an updated estimate of biomass and will be determined by the Commonwealth and not Seafood Tasmania. The large freezer vessel is able to fish further away from the coast than the relatively smaller boats who usually fish the SPF, moreover the fish are highly moble, so local depletions are highly unlikely. Such a vessel's fishing should be within sustainability limits developed scientifically by the host country, unfortunately - unlike in Australia - these are often absent and overfishing can easily result. In this case - the Small Pelagic Fishery - the proportion of biomass being fished is one of the lowest of all Australian monitored fisheries, Commonwealth or state. Its the bycatch that's the real issue.

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  3. Andy Saunders

    Consultant

    Colin;

    You raise a lot of points in your article, a few responses include:

    SED (lack of) research is a bit of a furphy. As you mention, "crucial trials have not taken place, due to...lack of activity" in the fishery (few/no mid-water trawls). This is just a chicken/egg situation, the proper course of action would be to have the Margiris undertake trials. After all, the Margiris is operated by the same company and personnel that are responsible for the SED research linked in your article…

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    1. Colin Hunt

      Honorary Fellow in Economics at University of Queensland

      In reply to Andy Saunders

      Andy, Thanks for your considered response. I am not suggesting that we ban the Margiris because of Australian fur sea seal mortality. That we cannot do unless the seal is listed as endangered by the Commonwealth.
      But I would like to see serious trials underway so that in future years Australian fur seal mortality is reduced to much lower than one in five interactions in the trawl fishery. If the company concerned would consent to undergo trials that would be an advance, but it will take many months…

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    2. Colin Hunt

      Honorary Fellow in Economics at University of Queensland

      In reply to Andy Saunders

      Andy, you query albatross mortality in the trawl. Fair enough, because longlining is the more obvious major culprit. However, albatross mortality is well documented in the trawl fisheries; they get caught in the warp during hauling.

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    3. Andy Saunders

      Consultant

      In reply to Colin Hunt

      Hi Colin. Longline comment was about seabird mortality, not for targeting small pelagics. In fact longlines consume a fair bit of small pelagics rather than catch them - used as bait.

      If you look at the dedication on the Jeremy Lyle Seal Exclusion Device/bycatch paper you'll see he is fulsome with his praise for the cooperation by several people. These are the same people who will be operating the Margiris so I think it is reasonable that they will also cooperate with SED trials again.

      My point…

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    4. Colin Hunt

      Honorary Fellow in Economics at University of Queensland

      In reply to Andy Saunders

      Andy, Apologies for my false reading of your point about longlining and sea bird mortality.
      Is bait fishing a big contributor to TAC in SPF? I doubt it.
      I hope you are right about the Margiris owners cooperating in SED trials, but note the scientific personnel and financial inputs also required for trials to proceed.
      Yes, bbq grilling does make the sardine and jack mackerel bones nice and crunchy.

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    5. Andy Saunders

      Consultant

      In reply to Colin Hunt

      Colin;

      Although the current Margiris plan is for export of jack mackerel to Africa as human consumption, I believe historically the majority of small pelagics in this fishery were marketed as bait, for tuna-ranching, long-line bait, rec-fishing bait Historically there was also fishmeal conversion which ended up as salmon feed and possibly other animal feed (poultry, pigs).

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  4. Damian Venn

    logged in via Facebook

    Why is it that commercial net fishing has been banned in parts of South Australia due to the effects it has on dolphins and seals but this boat is still allowed in our waters.

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    1. Andy Saunders

      Consultant

      In reply to Damian Venn

      Maybe because they didn't use BRDs? Maybe because it was a political decision rather than evidence-based?

      Given state waters only go out 3 nautical miles, this fishery is mostly Commonwealth rather than state (the quota is a federal one), and that I don't know of any Commonwealth bans (excluding MPAs for other reasons), it would seem a little irrelevant?

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