Surely one of the most common forms of seafood enjoyed in North America must be canned tuna. Many a kitchen pantry is stocked with a can or two, handy for quick, nutritious sandwiches or a simple casserole. The tuna in many cans is Skipjack, a fish that grows up to 3 feet long. Skipjacks live a short life, have a high reproduction rate and a high natural mortality rate, and is a pretty good choice for responsible consumers. The problem comes, conservation-wise, with the way it is caught.
Tuna for canning is usually caught by purse seiners. The fishing boats set large nets around floating objects, often Fish Aggregating Devices (FADs), artificial floating structures that attract tuna. When the nets are gathered in, it’s not just tuna that are landed. By-catch can be up to 50% of the catch, and can include billfish, wahoo, triggerfish, barracuda, rainbow runners, sharks, rays and sea turtles. The tuna catch itself includes both mature fish and juveniles, and may include yellowfin and juvenile bigeye tuna, both less plentiful than skipjack. Nets may also be set around whales and catch whales as well as tuna The whales escape by breaking through the nets. Theoretically.
The cans of tuna I looked at were labelled “Dolphin Friendly”. The Environmental Justice Foundation offers this information about tuna and dolphins:
The capture of dolphins that were deliberately targeted in tuna purse-seine nets in the Eastern Pacific Ocean caused an outcry when first brought to pubic attention. Tuna’s association with dolphins makes detection at the surface easier, but dolphins deliberately encircled by the purse-seiners were frequently captured and killed in the process. Dolphin mortalities reached hundreds of thousands every year, and populations declined rapidly until the mid-1990s when technological and operational changes to reduce dolphin by-catch were successfully introduced. The efficacy of these measures, in conjunction with management actions to limit dolphin deaths per vessel, has lowered mortality levels for all dolphin populations to less than 0.1%.
In other words, dolphin as by-catch has not been a major issue for about 15 years and the dolphin-friendly labelling is something of a “red herring”. In The End of the Line, Charles Clover reports that he had difficulty securing figures about tuna fishing by-catch. However, he was able to secure a report about a tuna fishing fleet making its way across the Indian Ocean. About 20% of its catch was endangered bigeye tuna. There were also oceangoing turtles including loggerheads, leatherbacks and others, most of whom are endangered. Whales that were caught included minke and humpback. Other fish included great white sharks, now listed as vulnerable, slow-growing manta rays, stingray and spotted eagle ray, hammerhead sharks and other seagoing sharks. No dolphins.
All in all, it would appear that a can of tuna results in the death of a lot more than just the skipjack tuna that ends up in the can. The most amazing thing is that all this lost sealife comes with such a small price tag. Check out the bin in the opening photo. If the cans were any cheaper, they’d be giving them away at the store entrance. What a waste.
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