Latest Issue of Science News

5/2/15 Cover


Gory Details

The bizarre side of science

Erika Engelhaupt
Gory Details

If you really hate a species, try eating it

More people are trying to get rid of the invasive northern snakehead by eating it, a strategy that can reduce numbers but probably won’t eliminate the problem.

Sponsor Message

For the Fourth of July, I went all-American. First my husband and I headed to Home Depot and bought a grill—that felt pretty American. Then we fired it up and cooked a meal fit for a red-blooded patriot. We did our part against an invading force, an army of slimy fish trying to take over the United States. We ate a snakehead.

It tasted like chicken.

Here in the D.C. area where I live, the northern snakehead (Channa argusis one of America’s Most Wanted. The fish is big, slimy and has jaws bristling with sharp teeth. It’s originally from East Asia, but turned up in the Potomac River in the early 2000s and started eating everything in sight. The snakehead has now invaded a swath of the U.S. East Coast and pockets across the country. Experts fear that it’s eating and outcompeting native fish.

But Americans are fighting back, with true entrepreneurial spirit. I bought my snakehead at a gourmet market. The District Fishwife in uber-trendy Union Market sells local snakehead, wild-caught by Maryland bow hunters. I would be doing a good deed to choose the snakehead, the fishmonger said, because I would be eating an invasive species. We should gobble up as many as possible to keep their numbers down.

So I did my bit, to the tune of $14 for a pound of the snakehead’s pink flesh. But it made me wonder: Can we really eat our way out of this problem?

A lot of people seem to like the idea. There are plenty of snakehead recipes online (most involve grilling or frying). There’s even a fishing competition devoted to catching — and eating — as many snakeheads as possible. The annual Potomac Snakehead Tournament awards cash prizes for the most snakeheads caught by bowfishing or hook-and-line. (Bowfishing, if you haven’t heard of it, is just what it sounds like: You shoot the fish with a bow and arrow.)

I asked one of the world’s leading experts on fishing, Daniel Pauly of the University of British Columbia, if he thinks we can fish the snakehead right out of our hair, along with other invasives like the lionfish (a poison-finned nasty that I hear tastes like lobster).

“Given the marvellous job we do at overfishing, depleting and otherwise dispatching species into oblivion, fishing and marketing for food invasive species such as lionfish and snakehead does seem a reasonable approach to me,” Pauly says. “If their biomass is kept very low, the damage they can do is lower.”

Sounds good. But we’re not off the hook yet. “I am well aware that some will use this possibility to suggest that invasive species are not a problem,” Pauly says. “We should ask someone suggesting this about the last time they have eaten ‘pasta con vongole,’ with zebra mussels substituting for the vongole.”

As Pauly says, we can reduce populations of some kinds of invasives, at least the tasty ones. But don’t take that to mean that we’re going to send American snakeheads the way of the passenger pigeon.

For one thing, snakeheads are hardy and adaptable, says Paul Angermeier, a U.S. Geological Survey fish ecologist and conservation scientist who teaches at Virginia Tech. And because these fish have lungs and breathe air, they easily survive transport to new locales (though Angermeier says it’s a myth that they can drag themselves from pond to pond by land).

“That kind of critter, once it gets a foothold, it’s going to do very well,” he says. At that point, options are limited. If the invader is in a pond, you can poison or drain the pond. But once they’re in open water, your options are down to fishing.

And as any fisherman knows, in a big river like the Potomac you’re never going to catch every last fish.

Now, ecology kicks you in the rear again. Any growing population eventually hits an environmental constraint: a limit on food, nutrients, spawning sites, what have you. The opposite is also true: A dwindling population gets a release from these constraints. “Eventually, everybody’s living on easy street,” Angermeier says. You end up with a small number of snakeheads in paradise, and they do very well. Reproductive success skyrockets. Before you know it, they’re back. This is one reason why bounties haven’t totally eliminated coyotes, Angermeier says.

So tournaments, sport fishing and demand at fancy gourmet markets are all fine, but we have to manage our expectations. These keep numbers down, and help educate people about what invasive species are and how to recognize them.

But the plan can still backfire. Once there’s demand for a fish as food and for sport, there’s also a perverse incentive to stock more waters with them. That may be what happened in 2002 in Crofton, Md., when a pond turned up chock-full of snakeheads. All it takes is one yahoo with a cooler.

What’s more, thinking that we’re solving the problem can make people less likely to make the hard choices that would prevent the spread of invasives in the first place, like barring more species from entering the country.

So keep all that in mind, and by all means, throw another snakehead on the barbie. We’re going to have to eat quite a few just to keep the population in check.

My recipe: seven minutes for a filet, skin side down, at medium heat on the grill. Great with mango salsa. And really, it is very much like a chicken breast. Maybe we could try Snakehead McNuggets. But we don’t want to encourage the establishment of a long-term fishery…. Got it.  Snakehead McRiblets, for a limited time only.

Follow me on Twitter: @GoryErika

 

More Earth & Environment articles