International Pacific Halibut Commission biologists are studying recreational discard mortality in Southeast and Southcentral Alaska to examine the impact of halibut release practices and associated mortality.
Charter vessels selected to participate in areas 2C, in Southeast Alaska, and 3A, in Southcentral Alaska, must complete their recreational discard mortality sampling by June 30, the IPHC said.
The 2021 research is a follow up to a study done on the commercial halibut fishery several years ago, where the IPHC stratified the fish into different injury rates, said Ian Stewart, a quantitative scientist with the IPHC. Information gathered during that study is still being evaluated.
The survey goal is twofold. One, the IPHC wants to evaluate effects of fish handling practices on injury levels and their association with the physiological condition of captured halibut. They also want to investigate effects of fish handling methods and associated injury level and physiological condition on post-release survival of these halibut in the guided fishery.
Each fish is to be measured, weighed, evaluated for injuries, sampled for blood and fat content, scored a survival viability and subsequently tagged and released. No fish are to be retained for consumption or other reasons.
Stewart noted that the IPHC does stock assessments on an annual basis, and that discard mortality rates are currently part of their ongoing research. About 5-7%, or one out of every 20 fish discarded end up dead, he said.
“Given the large numbers of fish handled each year, this is one area where we have a large amount of uncertainty,” he said.
“The IPHC can make recommendations about handling processes and gear types,” he added. “We generally work with National Marine Fisheries Service and the North Pacific Fishery Management Council on this. It would be good to know, if we could document differences in gear types, which gear causes the least harm to halibut.”
“Halibut are an incredibly resilient fish,” he remarked, “but nonetheless, it’s still an appreciable amount of mortality. Regulations require minimizing mortality to the degree possible.”