Fishing: what we don't keep.

As any angler knows, fish thrown back-because they're too small, the wrong type, or hunted only for sport-often don't survive. Because of the trauma they undergo when they are hauled in the net and taken out of the water for sorting, virtually all fish that commercial trawlers throw back are dead by the time they hit the water. This by-catch can be staggering, a new study illustrates.

In work done for the Alaska Department of Fish and Game (ADFG), Larry Cotter of Pacific Associates in Juneau sieved through an ocean of 1994 data for groundfish harvested commercially in the Bering Sea, Aleutian Islands, and Gulf of Alaska. The National Marine Fisheries Service (NMFS) defines as groundfish nearly all area fish except salmon, crab, halibut, and herring. Cotter's analysis, released earlier this month, reports that fishers discard 15 percent-some 651 million pounds-of the annual groundfish catch.

These discards included about 17 million pounds of halibut, 4 million pounds of herring, 400,000 individual salmon, and 15.5 million crabs. Ironically, though most trawlers had fished for pollack, this species accounted for more than 245 million pounds of discards, most of them the wrong sex or size.

With overharvesting causing the collapse of many fisheries around the world, Alaska Governor Tony Knowles responded to the report by proposing a new policy to make fishers keep all they catch, even the wrong sex and size. Indeed, he argued, last year's groundfish discards would have provided roughly 50 million meals.

However, notes Andrew Smoker of NMFS in Juneau, the law demands that fishers discard some types of by-catch, such as halibut. The requirement aims at discouraging trawlers from circumventing halibut fishery management by bringing in this valuable species as a by-catch.

A United Nations treaty, opened for signatures last week (SN: 12/9/95, p.389), also addresses by-catch losses of highly migratory fish and stocks-such as the pollack-that straddle nations' 200-mile exclusive economic zones. The treaty would require the ratifying nations to minimize such waste "through measures including, to the extent practicable, the development and use of selective, environmentally safe and cost-effective fishing gear and techniques."