Tuna or not tuna?
Dr Susan Lawler
This opinion piece first appeared in The Conversation on 23 August2011.
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.
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.
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.
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.
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.
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.
Dr Susan Lawler is Head of the Department of Environmental Management and Ecology at La Trobe University, Albury-Wodonga