Trouble In The Trout Family

When a Southern Pacific freight derailed near the town of Dunsmuir, Calif, on July 14, spilling nearly 20,000 gallons of a potent pesticide into the Sacramento River, it created an ecological blank slate: 45 miles of prime riverine habitat reduced to complete sterility. Unlike an oil spill, though, the chemical didn't linger, and by the end of last week the waters were clean enough to support fish. For state Fish and Game officials, that left the question of which fish.

The answer is of great moment to anglers, travel agents and trout. Left alone over the next decade, wild rainbow trout swimming in from the Sacramento's tributaries would rebuild populations to the prespill level. The quicker solution would be to dump hatchery fish into the river right now-to be caught tomorrow. But faster is not always better. Trout raised in hatcheries are more gullible than their free-born cousins, apparently because, having been fed by machines most of their lives, they associate people with food rather than frying pans. To a true fisherman, that makes the fish too easy to catch.

For the fish, restocking is likely to start a brawl. In streams where both hatcherybred and wild trout compete, the domestic strain sometimes crowds out the natives; biologists say the hothouse variety fail to recognize the signals by which their wild cousins keep one another at a distance. Some experts, like Maryland's director of inland fisheries Robert Bachman, maintain that adding hatchery trout to a wild population may actually result in a net loss of fish. "There's a gradual awareness," Bachman says, "that the solution is not just to dump more trout in trout streams."

Environmentalists worry about the gene pool. Wild and hatchery trout may interbreed, which threatens the genetic individuality of the wild stock. "We don't want chemical pollution followed by genetic pollution," says Tom Hesseldenz, regional manager for California Trout, a state group that tries to preserve rivers for fishing.

To many merchants along the river, who depend on angler-related tourism, and to the railroad, which has to pay the damage claims, a quick restocking is clearly desirable. These proponents point out that small numbers of hatchery fish have been introduced into the river in the past without threatening the natives. But with all the wild trout dead, the equation may have been altered in unknown ways. State Fish and Game officials plan to proceed with caution. "This is all virgin territory," says spokeswoman Mary Gail, likening it to Genesis. One interested group is the bald eagles that live in hills along the river. Fish and Game officials, concerned about how the birds would fare without trout, released some hatchery fish last week into carefully penned "fish corrals." If the trout were easier to catch than usual, the eagles, at least, didn't seem to mind.