IPHC preps for annual PWS setline survey

Biologists at the International Pacific Halibut Commission are gearing up for their 2020 setline survey of Pacific halibut, from northern California to the Aleutian Islands, this year to include 1,300 stations, including 40 to 50 for Prince William Sound.

This year’s survey of Area 3A, a charter area that encompasses Prince William Sound and the rest of southcentral Alaska, will include the same stations as fished last year, said Stephen Keith, assistant director of the IPHC.

“For the next two to three years our assessment is that the stock will continue to go down,” Keith said. “That’s been consistent.

“It was at historical high levels around 2,000, came down fairly steeply until 2010 and had been stable, but has been decreasing more gradually since 2016,” he said. “The commission has responded appropriately by lowering catch limits.”

All halibut harvested during the survey are sold to processors to cover the cost of the coastwide survey, which runs about $5 million to $6 million, Keith said. The survey is designed to be revenue neutral under the Halibut Treaty, signed back in 1923 by the U.S. and Canada. If needed more stations will be surveyed to cover costs, he said.

Each year the IPHC accepts bid from longline vessels which are charters for the survey, which provides data to be used in the Pacific halibut stock assessment. IPHC scientists then study various aspects of the Pacific halibut resource including growth, distribution, biomass, age-composition, sexual maturity and relative abundance of other species. Legal size Pacific halibut from all areas and some bycatch is retained, sampled and then sold to offset survey costs.

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Using data that goes back 140 years, the IPHC has noted that stocks have gone up and down.

One hundred years ago halibut stocks were high. When commercial fisheries began in 1888, harvesters fished really hard and stocks declined, so the US and Canada got together to form the IPHC, Keith said.

In the 1920s and 1930s abundance leveled out, then went high in the 1980s and 1990s, he said.

The IPHC management strategy involves both scientists and stakeholders who work together to figure out an acceptable range of fishing pressures and right now the catch limits agreed on are within that range, he said.

The overall 2020 setline survey will cover 28 charter regions within the IPHC conservation area, with a standard grid of stations from Oregon to the northern Bering Sea, including the Aleutians. The survey must be completed between May 23 and Aug. 31.