[Alaska Sea Grant]

Key to reducing bycatch may be taking
the ocean's temperature

Date: February 24, 1997
Contact: Ron Dearborn, 907-474-7086; Allison Barns, 907-474-7990

FAIRBANKS, Alaska--Reducing the number of unwanted fish caught in the state's multimillion-dollar-a-year trawl fisheries has long been the goal of scientists, environmentalists and fishermen. Now, a graduate student at the University of Alaska Fairbanks is taking a new twist on the bycatch problem.

"I'm trying to understand the depths, temperatures, and light preferences of commercial fish species," said researcher Allison Barns. "If we can better understand the ocean conditions different fish prefer, fishermen can use this information to avoid species they don't want to catch."

Barns is a graduate student studying fisheries oceanography at the University of Alaska Fairbanks. Her research is based on knowledge that fish such as salmon are sensitive to temperature changes of as little as half a degree. Japanese fishermen have for years looked for layers of warm ocean water, called isotherms, to find yellowfin sole and other species.

"If, for example, we can determine that pollock favor certain ocean temperatures and are sensitive to other conditions, that information can be extremely useful to fishermen trying to reduce their bycatch," said Barns.

Barns became interested in finding ways to lower bycatch while working with fisheries observers in Kodiak who collect data about the state's pollock, cod, sole and other commercially important species. She said the job put her in contact with fishermen concerned about wasteful fishing practices.

"Commercial fishermen are directly involved in making this project work," said Barns. "They voluntarily put environmental recorders on their trawl nets because they see there is a potential for the information to help them fish more cleanly."

Some 32 trawler captains have volunteered to carry the recorders on their nets. The devices record the net's depth, surrounding water temperature, and the amount of visible light as the net is pulled through schools of fish.

Back in the lab, Barns compares the data with the vessel's catch. She looks for oceanographic trends that may help fishermen single out the species they want to catch.

"Some of these principles are not new to fishermen," Barns said. "What's lacking is our understanding of how temperature and other factors affect different fish species." Barns' research has attracted the attention of the fishing industry. The National Fisheries Institute and the University of Alaska Sea Grant Program recently awarded Barns a $12,000 John G. Peterson Scholarship. The scholarship is named for the former president of NFI and past chair of the North Pacific Fisheries Management Council.

"This scholarship gives the University of Alaska Fairbanks a valuable tool to recruit and retain students engaged in critical research," said Ron Dearborn, director of the Alaska Sea Grant Program. "It also furthers the Sea Grant goal of expanding partnerships with industry to find solutions to the problems affecting Alaska's marine fisheries."

Each year, Alaska's trawl fishermen toss overboard some 750 million pounds of unwanted fish. The waste has sparked a national campaign by environmentalists and fishermen themselves to reduce bycatch. The newly reauthorized Magnuson-Stevens Fishery Management and Conservation Act, which sets management policy for fisheries in federal waters, makes reducing bycatch a national priority.

The Alaska Sea Grant College Program is a marine research, education and outreach service headquartered at the University of Alaska Fairbanks, School of Fisheries and Ocean Sciences. It is funded by the National Oceanic and Atmospheric Administration in partnership with the state of Alaska and private industry.

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