The Chernobyl Tomato

It’s called Lone Lake, but don’t let the name fool you—it’s anything but lonely. There are lots of homes around it, many with nice lawns extending down to the shore. There are also several farms where cows, horses, and alpacas graze. The lake is always busy with fishermen and boaters, and swimmers in season. It’s far from a wilderness angling venue, yet for me Lone Lake has two important virtues: It holds rainbow trout, some of large size, and it’s only about 15 minutes from my home. That makes it a handy place to drop in for a few hours of fishing.

That’s what I was doing one spring afternoon when large chironomids were hatching and trout were nosing through the surface to take them. I tied on a chironomid pupa imitation to match the naturals, and cast to a subtle rise tight against the weeds where big trout often cruise. I gave the fly a little twitch, felt immediate resistance, set the hook—and this THING began moving ponderously toward the center of the lake, taking my fly line with it. It wasn’t the swift run of a rainbow, but more of a strong, slow, steady pull, as if I’d hooked a power lawnmower.

Muskrat? Beaver? Somebody’s escaped pet alligator?

None of the above. When the thing finally came to the surface, I saw I had hooked a hugely fat, hideously ugly grass carp, Ctenopharyngodon idella. When I saw how big it was I knew I’d have to handle it carefully on the light tackle I was using.

The carp made several short, strong runs, taking line each time, then headed for the bottom where it grubbed around like a pig rooting through a landfill. After about ten minutes of this it finally returned to the surface, rolled onto its fat side, and came obligingly to my boat.

It was built like a garbage bag, which made it difficult to estimate its weight, but my guess was somewhere between five and ten pounds. Grass carp are supposed to be vegetarians, but this one obviously hadn’t gotten the memo; it had clamped down hard on my chironomid pupa imitation, which was stuck firmly in one of its thick, disgusting lips. I didn’t want to touch the ugly thing, but I did want my fly back, so I reached out and managed to twist the barbless hook free without even touching the fish. I watched the carp swim slowly away, then threw up.

Just kidding. I didn’t really throw up. I sure thought about it, though.

Although it wasn’t my intention, I had just proved grass carp can be taken on an artificial fly. Keep that in mind as you continue reading.

How the carp got there is an interesting story. Lone Lake has long been a popular place for people to empty their goldfish bowls, and God alone knows what all is swimming around out there. At some point, one of those goldfish bowls contained Brazilian elodea, a fast-growing invasive weed that quickly gained a foothold in the lake. It spread so rapidly that within a few years vast areas of the lake became clogged with weed and were no longer usable for fishing, swimming, boating, or anything else. The lake was on the verge of becoming a marsh, the next-to-last stage before it would become a meadow. Something had to be done to stop the weeds, and the Lone Lake Homeowners Association, the county government, and several local fly-fishing clubs banded together to seek a solution.

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Once nuclear weapons were ruled out, the groups decided to treat the lake with an herbicide that kills Brazilian elodea but is harmless to fish and insects. The results were immediate and dramatic: Great clots of dead weed floated to the surface and washed ashore, and suddenly all of Lone Lake was again open for fishing, swimming and boating.

The effects of the herbicide were only temporary, however. Something more was needed to keep the weed from coming back. Grass carp had been used for this purpose in other settings, with mixed results, but they appeared to offer the most promise, so the county applied for a state permit to plant sterilized Ctenopharyngodon idella in Lone Lake. State fisheries managers understandably weren’t thrilled at the idea of introducing a new exotic species, even if the carp were sterilized, and denied the permit. Twice more the county applied, and finally, in the absence of any other remedy, the state reluctantly approved.

The next step was to figure out how many carp should be planted. The available scientific literature was sketchy, lacking any established stocking formula, but biologists eventually came up with a figure of eight fish per acre. Since Lone Lake has 101 surface acres, that meant 808 carp.

I don’t know where they got the carp—Mars, maybe, or some equally alien venue—but 808 sterilized grass carp were planted in Lone Lake in the spring of 2007. At the time of ­planting, they averaged about 12 inches in length, but they can live up to 10 years and reach weights of 40 pounds under optimal grazing conditions.

The carp wasted no time doing what they were supposed to do, chomping every weed in sight. Periodic sampling of the lake showed steadily declining levels of aquatic vegetation. In fact, after a couple of years, sampling showed no aquatic vegetation whatever. That explained why anglers had begun to notice declining insect hatches; there was no longer any aquatic weed habitat for insects to breed in or feed in. It also explained why the trout in Lone Lake were beginning to look skinny.

Worse was to come. Removal of the aquatic vegetation allowed water-borne nutrients to become concentrated in blue-green algae, resulting in thick blooms toxic enough to kill house pets.

It was obvious things had gotten seriously out of whack, as often seems to happen when one exotic species is used to try to control another. Something had to be done to reduce the population of super-efficient carp in order to restore a balance between weed growth and carp numbers; otherwise it probably wouldn’t be long before Ctenopharyngodon idella started hungrily eyeing the well-kept lawns of lakeside residents.

How do you thin a population of grass carp? Easy: You just ask fishermen to catch them. State fisheries managers invited members of the Whidbey Island and Evergreen Fly Fishing Clubs to join in a special carp-fishing season with a goal of reducing the carp population by about 160 fish.

But there was a catch: To reduce impacts on nontarget fish species, such as trout, carp anglers would be required to use “barbless hooks baited with baits attractive only to grass carp. These include lettuce, spinach, alfalfa, sunflower sprouts, grass clippings, cherry tomatoes, and fresh fruit.”

That’s an actual quote. I’m not making this stuff up.

Why anyone thought fly fishers would be interested in a fishery requiring the use of fruits and vegetables for bait is beyond me, especially when I knew from recent experience that grass carp could be taken on an artificial fly. If they’d take a chironomid imitation, why not imitation fruits and vegetables?

That idea, however, apparently was never considered, and as this is being written the special fruits-and-vegetables-only carp season has been under way for several months. From what I hear, it’s not going very well. Not very many anglers have participated and not very many carp have been caught, even though various combinations of garden produce and ripe fruit have been employed. One determined local fly fisherman, obviously not a purist, even tried chumming with grass clippings.

Too bad. Just think what might have been: If anglers had been allowed to use artificials, every fly tier in the state would have descended on Lone Lake, anxious to try his or her own hand-crafted fruit and vegetable imitations. Imagine the new flies we’d all be talking about: Lefty’s Lettuce. Skykomish Sunripe. Woolly Rutabaga. Sparse Grape Hackle.

The carp wouldn’t have had a chance. By now the weeds would be growing back in Lone Lake, the bugs would be hatching again, and the literature of fly fishing would have a whole new genre of patterns to celebrate: Beethead Nymph. Crazy Chardlie. Eggplant-sucking Leech. Kale Morning Dun. Chernobyl Tomato.

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Steve Raymond is the author of many fishing books including Nervous Water: Variations on a Theme of Fly Fishing (Lyons Press, 2006).