Unintended Consequences in Tuna Fishing

In the 1980’s, fishermen trawling for tuna killed tens of thousands of dolphins each year, scooping them up as “bycatch” in their nets. A public backlash spurred development of a “dolphin safe” fishing method — which, while great for dolphins, turns out to be a catastrophe for sharks, sea turtles, mahi-mahi, and other sea creatures, many of them endangered. Dolphin-safe fishing is also a less ecologically sustainable way to harvest tuna stocks. The Southern Fried Science blog has the grisly details, showing that eco-reform, like everything else, is beholden to the law of unintended consequences. [%comments]

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  1. Phil says:

    In fairness, I think part of the argument is that dolphins are so intelligent that they have a right to not be killed. That right doesn’t apply to sharks or sea turtles, so advocates of dolphin-friendly fishing methods might not be all that concerned about those particular consequences — unintended or not.

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  2. hunter says:

    paraphrased: “saving 1 dolphin equals the death of 382 mahi-mahi, 188 wahoo, 82 yellowtail and other large fish, 27 sharks, and almost 1,200 small fish”

    it has always struck me that “dolphin-free” tuna was very artificial anyway. why not “turtle-free” tuna? those turtles are at least as cute as the dolphins…

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  3. Peter says:

    There should be a “public backlash” for overfishing tuna. When already low tuna stocks becomes depleted, you’ll be signing the reverse song of the law of unintended consequences.

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  4. DaveyNC says:

    There should be a public backlash over animal rights activists grandstanding when the “cute” animals are involved. We’re at the top of the food chain and I, for one, prefer to stay there.

    I’m having tuna for lunch today.

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  5. charles says:

    Peter – only some species

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  6. frankenduf says:

    the market is not so safe for dolphins- check out the documentary – “the Cove”

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  7. Anonymous says:

    Hah! This is a classic example of opportunity costs, the most important part of someone’s decision making process. Reading the first sentence you can assume that the method fishers used was inefficient. Then as you keep reading you might be relieved when they developed a “dolphin safe” method. Now it results that dolphins are safe, but what about sharks, turtles and mahi-mahis and other similar bycatch creatures that aren’t? There’s a huge opportunity cost for both ways of fishing, both will kill bycatch animals, but which method is more efficient? It’s either dolphins or sharks and the other similar creatures or not fish tuna at all. I think the government should interfere by thinking at the margin and establish rules. They can develop a new way of tuna fishing without harming other animals, and if they can’t, keep the same method (only if the profit gained from tuna exceeds the cost of killing the bycatch animals) or not fish tuna (only if the benefit of not killing the bycatch animals exceeds the profit gained from tuna). I only warn them to think rationally at the margin but all the decisions will have costs, choose the one they think has the least cost, where the benefits exceed the costs.

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  8. BSK says:

    No one realized the irony in making the hunting of one type of animal safe for a different type of animal? Obviously, you’d rather not cause the needless death of an animal. If the tuna will be eaten, that is useful. If the dolphin dies and discarded, that is needless and ideally would be avoided. Yet, if more animals are dying as a result, well, we haven’t really done anything to improve things.

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