Fishing Lines: Changing the laws of natural selection

THE freshwater bass, America's most popular fish, probably owes its continued popularity to the fact that fishery scientists can't play God with its genetics. Smallmouth and largemouth bass don't take kindly to the gilded cage and three meals a day treatment that salmon and trout meekly accept. Maybe that's why bass fishing in the United States is flourishing, whereas salmon and trout anglers are now conceding that artificial rearing may actually be the problem rather than the solution.

Here's what happens. When the prodigal salmon return, they are trapped, their eggs stripped and fertilised. The baby salmon hatch and are fed until they are big enough to avoid predators and get their own breakfast. Then they are put back into a river or lake.

Yankee fishermen are among the crudest in the world. This is because there are so many fish in most of their waters that a total duffer will catch a netful. Fishermen here have got used to this super-abundance, and come to expect it. And listen, we are talking 38 million people here. Lots of votes if they keep catching lots of fish.

Unfortunately, the public also demands luxuries such as electricity and water. In many states, this is provided by dams and hydro- electric stations. However, it's a pretty nifty salmon that can negotiate half-a-dozen 100-ft dams. Rivers in states such as Maine, where fishing was once so good that the bears got fed up with salmon, now rely on stocked fish.

Can't see the catch? Nor can most of the fishery biologists. But here's what happens. In the wild, the smaller, sickly fish would not be able to breed. But what has happened in Maine is a typical example of how man's interference can screw up hundreds of years of genetic selection.

A 3lb landlocked salmon is now an exceptional fish on waters that once produced 10-pounders regularly. Their life span has halved, to just over seven years, while brook trout only live for an average two-and-a-half years. Wayne Hockmeyer, who has fished the state for most of his life, tried to voice the anglers' fears to the fisheries department, but got a hostile reception.

'The trouble is that in a hatchery, every fish survives. There is nothing to eliminate the weaker ones. They pass their genes on in large numbers, and soon small, slow-growing fish are the norm. This is a business and political thing. If you close the hatcheries, you put people out of work, perhaps even the people from the fisheries department.

'They have tried the quick, easy solution. What we need is a long- term programme to set up artificial spawning areas, using very large wild fish. But it will cost a lot of money, take a long time and even then, the results are uncertain. No bureaucrat will risk his career on such a thing.' And so Hockmeyer now fishes solely for bass, which refuse to play the artificial mating game and so grow big and healthy.

The Maine experience is far from unique, and it is a lesson for the British. With a continuing decline in Atlantic salmon returning to our rivers, there is growing talk that salmon farms will save the day. On the contrary. They may be the factor that results in the wild fish's extinction.