SCIENCE BEHIND THE SUCCESS: NOAA TO AGAIN CONDUCT GULF OF ALASKA BOTTOM TRAWL SURVEY
May 18, 2011
One reason for that success is the science that goes into groundfish and invertebrate stock assessments here in Alaska. To gather data for that stock assessment in the Gulf of Alaska, NOAA researchers from the Alaska Fisheries Science Center conduct a bottom trawl groundfish survey of the continental shelf and upper continental slope of the Gulf of Alaska every other year.
The "U.S. Research" label affixed to this charter vessel indicates it is involved in the Alaska Fisheries Science Center's biennial Gulf of Alaska bottom trawl survey.
"We like to make sure the public is aware of this survey," said Guy Fleischer, deputy director of AFSC's Resource Assessment and Conservation Division. "Given that these chartered trawlers sometimes show up only occasionally along the coast, many communities are caught unawares and may be concerned until they realize it's just us NOAA fisheries biologists doing our regular survey."
The vessels will embark from Dutch Harbor, Alaska, on May 18, and begin sampling operations near the Islands of Four Mountains – about 180 miles southwest of Dutch Harbor. Sampling will continue as the vessels move eastward along the continental shelf and slope to the U.S.-Canada border near Dixon Entrance.
The cruise will last about 90 days and will be split into four legs with breaks at Sand Point, Kodiak, and Seward to exchange crews, re-provision, and take on fuel. Both vessels will complete their charters and offload in Ketchikan between August 10 and 15.
Once the survey is complete, scientists will finalize the data they collected on fishing effort, catch rates, and biological characteristics of the fish populations (size distribution, age, growth rates, diet, etc.) and generate fishery-independent estimates of geographic and depth distribution, abundance, and population size and age composition by the end of September.
Stock assessment modelers will then combine that information with data from the fishery and results of previous surveys to update the stock assessments produced annually for the North Pacific Fishery Management Council to manage the groundfish stocks of the Gulf of Alaska.
"Our fisheries stock assessment teams use the newly gathered data as well as the historic data to help determine the health of the resources," said AFSC Director Doug DeMaster. "That data is then used to inform decisions about future management and fishing activities in the Gulf of Alaska to ensure the sustainability of the fish stocks for current and future generations."
The series of surveys started in 1984, with surveys being completed every three years until 1999. For the past 11 years, the survey has been carried out every other year.
In addition to staff scientists from NOAA's Alaska Fisheries Science Center, researchers are also participating from the International Pacific Halibut Commission, California State University-Humboldt, University of Washington School of Aquatic & Fisheries Science, Memorial University of Newfoundland, Colorado State University, and University of Mississippi.
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