Eating Aliens: One Man's Adventures Hunting Invasive Animal Species (13 page)

Justin soon had a smaller carp, then Patrick hauled in a mirror carp. At first glance, the mirror carp looks like a different species. It has very few scales, which are widely distributed over its body, as opposed to most other carp, which have plenty of scales close together. In fact, mirror carp are simply a kind of common carp that has been bred by humans for its lack of scales.

Carp don’t chase down their food. They are mostly herbivorous, though all species will swallow invertebrates and even smaller fish if they have the opportunity. They’ll also take a worm on a hook now and then. Anyone fishing for them should cast the bait and then leave it alone for a while, so I put my ball of oatmeal on its hook and let it settle to the bottom of the river. I rested the rod on a forked stick to wait for a bite. With my hands free, I decided to see what I could catch with a rubber worm and the lighter rod I’d borrowed from Patrick.

This turned out to be a mistake. Hoping for a bass, I hooked what I can only presume was a good-size carp. The light rod strained at the heavy weight, bent almost double, then snapped off. The line broke with it. I stared in disbelief at the dark, blank water for a moment before reaching into my pocket for a twenty-dollar bill, which I handed to Patrick as compensation for his rod.

We took a few more common carp before stopping for the day. Back at Patrick’s house, we cleaned the fish. I froze enough to fill the cooler for the trip home to Virginia a few days later.

At home, I smoked some of the carp, and it went nicely on toast for breakfast. There was no foul taste, and for a fish so big, I didn’t find it to be at all bony. It tasted as good as any other common whitefish, though a bit blander than the game fish, such as crappie and sunfish, that American fishermen are accustomed to eating.

As for the carp in my parents’ pond, the battle continues. In addition to nets, standard tackle, snag hooks, and corn, I’ve chummed oatmeal balls and anything else that ought to work. The fish dive and disappear as soon as I show up.

Many American anglers think of carp as, well, carp, and fail to recognize the various species. Each has a story behind its introduction and may require a different approach to catching it. Common carp were brought to the United States much earlier than were grass carp. German immigrants were accustomed to eating and fishing for them back home and first released them into the wild in the 1830s. Later that century, there was a series of efforts by the federal government to introduce common carp to American rivers. They were touted as a miracle food that would feed a growing country. Carp do indeed grow very large very quickly and can provide a lot to eat with one catch. But carp never became as popular a food as the government had hoped.

The carp that most recently is loathsome to Americans is an invasive species called the silver carp. This Asian native is notorious for leaping high into the air at the sound of an approaching motorboat. Seeing one fish do this is remarkable. When a hundred are leaping at once, it’s downright surreal.

Silver carp were brought to this country, for aquaculture purposes, in the 1970s. At the time, the species was appealing because of its astounding efficiency at converting suspended phytoplankton in the water into fish flesh. It doesn’t need to deliberately feed; it’s equipped with a unique spongy pad on its gills that soaks up the finest of algal particles from the water as the water passes into the mouth and through the gills. This fish literally eats as it breathes.

Aquaculture researchers looked at this trait and the rapid growth of silver carp as being ideally suited to turn wastewater treatment facilities into centers of food production. The high phosphorus content of the sewage resulted in huge blooms of plankton, which a carp could transform directly and rapidly into protein, growing up to a foot in length in its first year of life.

From the aquaculture perspective, this plan worked extremely well. The fish thrived in the wastewater ponds. There were, however, two problems. First, the FDA didn’t even want to discuss the idea of allowing the carp to be sold as food. After all, let’s face it, these fish were swimming around in water contaminated with human feces. Who wants to eat the poop fish?

The second problem was that despite the research that private businesses and federal agencies had conducted in advance, the fish escaped into the wild, and did well there, too. Nobody had predicted or even thought this would happen, mostly because silver carp didn’t seem to spawn readily outside of their native range. Research had suggested that silver carp wouldn’t be a problem if they escaped. One of the funny things about silver carp, though, is that even when they’re hardly spawning at all, you still end up with a lot of fish. The fry grow so fast that they quickly reach a size that protects them from most predation. When they’re still small, they don’t need to stray far from protective cover in order to feed (especially if there’s a lot of phytoplankton around for them to take in as they breathe).

Eventually, it became clear that the silver carp in the wastewater treatment ponds were spawning and that the eggs were drifting many miles downstream. The mature fish became established in rivers all over the Midwest, and in some stretches of river, they now constitute up to ninety-five percent of the animal biomass.

The stories I had heard about invasive silver carp sounded too strange to be true, especially the one about their habit of leaping out of the water in response to the sound of a boat’s engine. Imagine: enormous silver fish hurtling through the air at speeds fast enough to kill somebody and sometimes jumping into a boat. A refreshing change from conventional fishing, that’s for sure.

After watching grainy YouTube videos of these leaping carp, I desperately wanted to see the phenomenon for myself. I also wanted to eat one. Carp in general have a reputation among American fishermen for being inedible, even though most of those fisherman have never actually tried it. I don’t dismiss anything that moves as a food source until I’ve eaten it myself.

Out of the blue, I received an invitation from Jim Low, whom I had met at an outdoor writers conference in Utah. Jim is president of the Outdoor Writers Association of America, and also happens to be the print news coordinator for the Missouri Department of Conservation. Would I like to come out to Missouri for a few days and see these silver carp in action? Would I like to cook up a mess with one of the agency’s biologists?

I told Jim I’d be hitting the road as soon as humanly possible.

I didn’t even have to pack. By that time, I’d been on the road hunting and fishing for alien species for the better part of a year. The crab traps, fishing rods, guns, camping gear, and spices lived in the car. My suitcase hadn’t been emptied in months.

I made the eight-hundred-eighty-eight-mile drive to Columbia, Missouri, in two days. There was a time when I would have tried to do it all in one, but during my adventures in the last year, I had come to enjoy a lot of small things about being on the road. Eating at run-down old barbecue joints and roadside fruit stands. Pulling off to check out a state park, curious after seeing a sign. Picking up a hitchhiker on those rare occasions when there was room for a passenger. You miss out on those things when you try to rack up almost nine hundred miles in a single day. Not to mention that driving as you’re falling asleep is a recipe for disaster.

Once I’d gotten out of the familiar mountains and coal country of Virginia and West Virginia, the landscape was new. I crossed a river and went through a big town full of smokestacks and soon found myself in the midst of low, steeply rolling hills covered with grass and dotted with stands of hardwoods. I thought of hills like these as foothills — a prelude to mountains a short distance away. But these hills continued on as far as I could see.

I was into real horse country now and closing in on Lexington, Kentucky. The road cut through blasted-away sedimentary rock with unfamiliar layers of geological stories; I wanted to pull over and climb onto those man-made cliffs and look at the rocks up close and touch them. On an interstate highway, though, that’s usually frowned on.

Eventually those low grassy hills gave way to more trees until, suddenly, I became aware of the absence of hills with that keen, eerie sensation that is understood by anyone who grew up surrounded by mountains. The landscape was flat and open to the wide sky above. I was into Indiana, then Illinois. Cornfields lined the road, most of them low and brown with drought. I stopped in a town called Burnt Prairie, looking for lunch and finding only a gas station.

Missouri is a state I still can’t quite get a handle on. Sometimes it feels like the Great Plains and other times it seems like the South. Even the accents are all over the map.

I met Jim in the parking lot of a Department of Conservation field station in Columbia. We were quickly joined by biologist Vince Travnichek, who manages the field station. One of Vince’s employees, Kevin, drove a pickup truck into the lot with a surprisingly large flat-bottomed boat in tow. We loaded the boat and truck with gear and drove to a tributary of the Missouri River that Vince thought would yield some silver carp.

Vince is a slightly portly man of middle age who seemed quite cheerful for someone who had given up caffeine a few days before. Decades into a career in biology, he still had an obvious enthusiasm for his field, apparent whenever the subject of fish was raised.

We backed the boat down a ramp into the water and the men began setting up a pair of long steel booms off the bow. This was the electrofishing gear — dangling metal tubes like wind chimes that touched the water in order to conduct electricity into it. In fact, the whole boat was designed specifically for electrofishing. Now I was getting very excited; I’d long wanted to see this unusual fishing method in action.

Electrofishing is used by biologists to zap anything within range of the current. This causes the fish to rise to the surface, where they can be observed. Vince assured me that the fish (with one exception) are only stunned and more than ninety-nine percent of the fish he zapped while sampling would soon swim away and go about the rest of their lives with no trouble at all. The one exception is silver carp. For reasons not fully understood, they have a high mortality rate over the few days after being zapped. This was okay by me.

It turns out that electrofishing is not the silver bullet I had thought it was. The current doesn’t go very deep, and bottom dwellers usually aren’t affected by it. Catfish, in particular, are underrepresented in electrofishing surveys. But this thing was still incredibly cool. Once we were under way, Jim and Vince flipped on the current, and a steady stream of baby shad bubbled up behind the electrofishing booms. I stood with a long-handled net ready to scoop up anything interesting. I handled a longnose gar for the first time. I saw buffalo fish and freshwater drum for the first time.

Suddenly something broke out of the water and landed with a smack about ten feet away. A carp! Then another, then another. We hadn’t been on the water for more than five minutes when I was able to scoop up my first five-pound carp from where it had been stunned by the electricity. The relief at dropping it into the live well was enormous. As of that moment, the trip was a success and I knew I hadn’t driven close to nine hundred miles, not counting the return trip, for nothing.

Carp were leaping everywhere. At times there were a dozen in the air at once. Pretty soon we didn’t even need the electrofishing gear. Huge carp were jumping straight into the boat without any encouragement from us. It was perhaps the most amazing thing in nature I’d ever witnessed. Big silvery torpedoes of some twenty pounds launched themselves out of the water as high as ten feet in a fast graceful arc right into the middle of the boat. They smacked into the aluminum and flopped around in bloody confusion as I tried to pounce on one, even as another came hurtling in.

It’s not often that anything turns out to be exactly as advertised. The silver carp situation in Missouri is one of those few.

As stunning as this was to experience, it’s a real problem on many rivers. Think about what happens when a twenty-pound missile of meat and bone hits you in the face. People have already suffered broken bones. One young man went through months of reconstructive surgery after his face was crushed by a particularly large carp. It’s only a matter of time before someone is killed; a small child could easily die from one of these hitting the wrong spot. Boaters realize this, and there has been a big reduction in pleasure boating on tributaries of the Missouri. This is not a good thing. When people stop seeing a river, they begin to care less about protecting it.

The oddest part of the story is that silver carp are not known for engaging in this behavior in China. They’ll jump now and then, but nothing like what happens in the United States. I’m reminded of the black spiny-tailed iguanas in Florida and their unexpected carnivorousness.

What the leaping silver carp and the rapacious iguanas have in common is that both of these invasive populations descend from a bottleneck population of just a few introductions. One explanation could be that an unusual characteristic — even one that’s actually disadvantageous — can become widespread if the other advantages the species has in that new environment are great enough. Such a characteristic, like jumping straight out of the water at the sound of a boat’s propeller, might disappear from the gene pool before it was even noticed by humans in the original and more competitive environment. When there are only a few individuals in a new habitat where there are few predators and an advantage in feeding behavior, that oddball trait could persist and eventually become normal.