A recent study funded by the ocean advocacy group Oceana shows that more than one-fifth of seafood caught nationwide is discarded at sea. Alaska, by comparison, comes out fairly clean with a 12 percent discard rate, the lowest among the eight regions managed by the U.S. National Marine Fisheries Service. Bycatch is a “serious problem in the world’s oceans” that can disrupt entire food chains and ocean habitats, the report says.

The study appears in the December issue of the journal “Fish and Fisheries” and details problem areas and species, and represents the first comprehensive accounting of the amount of bycatch in the United States. Fisheries consultant Jennie M. Harrington, Dalhousie University professor Ransom A. Myers and University of New Hampshire professor Andrew A. Rosenberg used federal data collected from 1991 to 2002 to calculate which regional fisheries inadvertently kill the most unwanted fish.

The report found that for every 3.7 million tons of target species caught, 1.06 million tons is thrown overboard. The worst offenders are Gulf Coast shrimp draggers, who discard four times as much as they keep and account for half of the waste nationwide. In 2002, Gulf Coast shrimp fishermen had a bycatch of one billion pounds. U.S. fisheries on average throw away 22 percent of what they catch.

In an article published in the Washington Post, Dalhousie University professor Myers talked about the impact of bycatch on overfished or depleted stocks.

“The scale of the problem here is enormous,” Myers said, adding that the annual wasted fish would fill every bathtub in a city of 1.5 million people. “And it’s an insidious problem, because we cannot have the recovery of fish stocks as long as they keep getting caught as bycatch.”

Susan Buchanan, a spokeswoman for the National Oceanic and Atmospheric Administration, told the Washington Post that the agency “remains committed to further reducing bycatch through innovative technologies and management approaches, and NOAA’s investment in bycatch reduction programs have cut commercial fishing bycatch considerably in the last decade. NOAA Fisheries data shows that bycatch has dropped 50 percent in the Gulf shrimp fishery and substantially in virtually all other U.S. fisheries, benefiting the ecosystem and protecting our valuable marine resources.”

Susan Murray, associate regional director of Oceana’s branch office in Juneau, told the Juneau Empire that Alaska’s ranking in the report is mostly due to the low bycatch in its largest industrial sector: pollock. “If you look at (other trawl fisheries) ... we have some fairly dirty fisheries,” she said. According to federal data, bycatch in the pollock fleet is less than 2 percent of the catch.

In contrast, the Atka mackerel fishery in the Aleutian Island archipelago uses “rockhopper” trawl gear that rolls over obstacles on the sea floor — whether boulders or corals. Some trawl fisheries in Alaska end up discarding as much as 50 to 60 percent of their catch, according to Ben Enticknap, an Oregon-based project manager for Oceana who has analyzed the Alaska trawl fisheries.

The authors did not analyze bycatch of turtles, sea mammals or birds, but focused on fish and marine invertebrates. They also did not analyze two of Alaska’s major fisheries that occur partly in federal waters — salmon and crab — because bycatch is minimal for those fisheries.

Cristy Fry has commercial fished in Homer since 1978. She also has designed and built gear for the industry. She currently longlines for halibut and sablefish and gillnets salmon in upper Cook Inlet aboard the F/V Realist.