Commentary: New insights about an old fish


Bowfin. Image: Wikimedia Commons

By Dave Strayer

In books and movies, it’s common to discover that someone who we thought of as a good guy is really a villain, or vice versa – think of Severus Snape, who appeared to be Harry Potter’s nemesis, turning out to be his most loyal protector, for example. When this sort of thing happens in real life, it can be a little disorienting.

As a long-time angler and ichthyology student, I thought I knew a lot about the bowfin. But recent developments have shown that much of what I knew about this fish was wrong. I learned as a kid that bowfins are “trash fish” – not good for eating or anything else. They are supposed to taste like “mud-soaked cotton”. What’s worse, bowfins are voracious predators, so we always imagined they were eating all of the best fish before we could catch them. Like many other anglers, I was taught to kill any bowfins that I caught, to protect valuable sport fish populations. If ever there was a useless fish, it was the bowfin.

I learned in ichthyology class that the bowfin is a “living fossil”, the single surviving member of a line of fishes that was already around more than 100 million years ago. Something very like our modern bowfin was swimming around in prehistoric swamps between the legs of dinosaurs. Bowfins also have a number of interesting traits: they can breathe air, they ferociously guard their young, and they have a skeleton unlike any other modern fish.

But it turns out that I didn’t know the bowfin very well. A careful analysis of bowfin DNA and anatomy that was just published shows that there isn’t just a single species of bowfin, as has been so long assumed, but two, or maybe even four. The different species, though similar in appearance, each live in different parts of the United States and Canada. Probably only one of these species (Amia ocellicauda, which doesn’t yet have a common name) lives in the Great Lakes region. We don’t yet know whether the different species have different habits or abilities, or perform different roles in their ecosystems.

This discovery reminds us that we still have a lot to learn about the natural world. There still are secrets waiting to be uncovered, even about a large, familiar fish that lives in one of the best-studied regions of the planet. So it’s best to be a little humble about our understanding of the natural world. No matter how sophisticated, our knowledge usually isn’t the final truth.

The other recent news about the bowfin is that this most useless of fishes has turned out to be very valuable. How is this possible? Although bowfin meat is unpalatable, their eggs are now being made into delicious caviar. Bowfin caviar (sometimes dressed up as “Cajun caviar” or “choupique caviar”) costs about $10 an ounce, and is at the forefront of a movement to develop a sustainable American caviar industry from our native fishes.

As the bowfin shows, the value of a species can change dramatically from one time to another. If we had found in 1975 a way to kill all of the bowfins, probably nearly everybody (except for a few wild-eyed ichthyologists) would have been in favor of doing just that, and we never would have discovered the value of bowfin caviar.

The answer to “what is species X worth?” depends as much on human ingenuity and current fashions as on the species being judged. We may think that we know what a species is worth today, but there is no way to know what it will be worth tomorrow. This means that we should be very cautious when making irreversible changes to the natural world, like destroying habitats or extinguishing species.

So as we learned for Snape, don’t judge the bowfin (or any other species) too quickly.

Dave Strayer is a freshwater ecologist at the Cary Institute of Ecosystem Studies in New York.

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