Salmon Shark Lamna ditropis in the Alaska Region; Data Needs and Management Challenges

Sharks were previously managed as part of the other species category by the North Pacific Fishery Management Council but in 2011 this category will be dissolved and sharks will be managed as a group with uniquely defined overfishing levels. Shark catches within the Gulf of Alaska (GOA) are dominated by three species, the spiny dogfish, Squalus acanthias, the Pacific sleeper shark, Somniosus pacificus, and the salmon shark, Lamna ditropis. While not the target of commercial fisheries, salmon sharks are captured by recreational fishers and as bycatch in several fisheries within both state and federal waters of the GOA. Some of these sources of mortality, particularly in state-managed fisheries remain undocumented. The stock assessment and management of this species is further hindered by a lack of life history data to input into models. Parameters needed to support stock assessment include reproductive timing and periodicity, fecundity, and improved age and length at maturity estimates. Commercial fishers operating out of Kodiak, AK provided 18 salmon sharks to researchers at the Alaska Fisheries Science Center Kodiak Laboratory which were utilized to examine the reproductive biology of this species. The majority of these sharks were adult females (n = 14) captured during the fall months and preliminary assessment of their reproductive biology indicates a two-year reproductive cycle with a fecundity of 3-4 pups per litter. Additional data about the reproductive biology and mortality of this species are needed to support age-based demographic models of the salmon shark in the eastern North Pacific Ocean.