In Search of Fish Contraceptives

If you care about fish, stop them from having sex.

Probably the most convincing argument I’ve heard for eating animals—as with the most convincing argument for a lot of things—was a random observation by Tyler Cowen some fifteen to twenty years ago. From an interview with Peter Singer in 2009:

I have been very influenced by a lot of what you've written, but I'm also not a pure vegetarian by any means, and when it comes to morality, for instance, my view is that it’s perfectly fine to eat fish. […] [T]he utilitarian would look at the marginal impact and say, “most fish die horrible deaths anyway, of malnutrition or they’re eaten or something else terrible happens to them.” The marginal impact of us killing them to me seems to be basically zero. I'm not even sure a fish’s life is happy, and why not just say it’s fine to eat fish? Should it matter that we make them suffer? It's a very non-utilitarian way of thinking about it, a very moralizing approach.

Cowen’s argument is worth considering for a few reasons.

First, like any good argument, it knows its limits. Cowen isn’t saying anything here about factory farmed land animals or farmed fishes, which live miserable lives and wouldn’t exist if it weren’t for animal agriculture. There are basically no good arguments that defend factory farming, and Cowen isn’t looking for one.

Second, even though it says nothing about factory farming, Cowen’s argument is still meaningful. Most of the animals that people kill each year actually aren’t farmed animals. We slaughter over 80 billion land animals and 100 billion farmed fishes every year, but more than 1.1 to 2.2 trillion wild caught fish. If you count shrimps—and you should—the wild caught number goes up by 25 trillion.

Third, Cowen’s assumptions are all plausible. Should we think that fish in the wild live really bad lives? Plenty of smart people think so. A lot of fish die from disease, starvation, and predation, and those who survive might suffer in ways that we can’t even imagine. Should we think that’s worse for them than being killed and eaten? Maybe, and it’s at least worth considering. Is utilitarianism a plausible moral theory? You bet.

Finally, there aren’t any crazy good arguments that might make us think Cowen is destroyed by madness, starving hysterical naked. There are some good arguments that he’s wrong, but no crazy good arguments.

The best good argument is this: A few years ago, Tyler John and Jeff Sebo coined the term “Logic of the Logger.” This is the view that:

if most wild animals have negative well-being, then the world could be improved simply by ending the lives of these animals and destroying their habitats.

Even if destructive intervention in nature can successfully reduce animal suffering, John and Sebo argue, it would negatively affect our beliefs, values, and practices because people might conclude that it’s generally acceptable to harm animals. People have “at least partly deontological moral intuitions,” and even if our actions have positive first-order consequences, the second-order consequences for the ways we think and behave are probably bad.

That’s a plausible reply, but it won’t necessarily convince an act utilitarian that fishing is bad. Brian Tomasik argues contra John and Sebo that intervening in nature, including through destructive practices, models other values that are good, “such as not shrinking away from unpopular but quantitatively important moral stances.”

Thankfully, we don’t have to think as hard as John and Sebo to poke holes in the logic of the logger. Let’s consider a few of the empirical claims that make Cowen’s argument work.

• Does suffering dominate happiness for mature fishes? Typical arguments that nature contains more suffering than happiness point to the lives of immature animals, but they don’t delve a lot into the lives of mature animals. It’s possible that mature fish welfare is negative, but the question is unsettled—and at this point, probably not something we should be willing to bet trillions of fish lives on.

• Do fish suffer less when they’re dredged up from the ocean than they would if they remained in the wild? Again, we can’t be sure. There’s just not an obvious or intuitive answer. And if you give any credence to the argument that it’s worse to cause suffering than simply allow it to occur, a precautionary principle ought to come down against fishing.

• Does fishing actually reduce the number of suffering fish in existence? You might think the answer is obvious, but it’s not so clear. Fishing could reduce the number of fish, or it could make room for fish to reproduce more quickly until the ocean again reaches its carrying capacity. About a third of global fish stocks are decreasing (a perverse win for “ocean communism?”) but that’s just one part of the story. For every fish who’s killed and replaced, there’s a vast number of fish offspring who live very short lives of intense suffering and then die before they reach sexual maturity. Atlantic cod, for example, spawn somewhere around two million eggs per year. When you account for fish offspring, the total amount of fish suffering is likely far greater in the fishing scenario than the non-fishing scenario because fishing results in more reproduction to replace caught fish, and that means more fish are spawned even if the mature fish population is declining.

The last point is the most important. Fish sex is a really bad thing, and it seems like our best solution to the logic of the logger would be to find some way to meaningfully reduce the number of fish that are ever spawned. That’s a better solution than painfully killing trillions of fish, and it’s not irreversible or as unpredictable as destroying aquatic habitats. Now, we don’t have a way to do it yet, but I’m willing to bet there’s at least one wealthy-grantmaker-and-enterprising-young-grad-student duo out there that would be willing to do a plausibility-probing research study into fish contraception.

This is the first thing that comes up on Google when you search “fish having sex.”