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Advancing the Data-Limited Stock Assessments for Pacific Sleeper Shark (Somniosus pacificus) and Pacific Spiny Dogfish (Squalus suckleyi) in Alaska.

• Milo Adkison
• Andy Seitz
• Cindy Tribuzio (NMFS)

Garrett Dunne is originally from the granite state of New Hampshire. He earned his BS in marine science from Eckerd College in St. Petersburg Florida in 2015 and came to Alaska to work with salmon in Prince William Sound. He was amazed at the health of the marine ecosystem of Alaska in contrast to the depleted fisheries of New England. With the goal of conducting his own research in Alaska, he pursued an MS in marine biology from Northeastern University, completing it in 2019. During his education, field experiences, and time commercial fishing he became fascinated with deep-water sharks leading him to propose his current research. For Garrett’s Ph.D., he will examine the populations of Pacific sleeper shark (Somniosus pacificus) and Pacific spiny dogfish (Squalus suckleyi) with the goal of improving the stock assessments for these species. Garrett hopes his research will help maintain the vibrance of Alaska’s marine ecosystem and improve the lives of the people who rely upon them.

Sustainable stock management of fisheries is a priority in Alaska, though data-limited stocks present a continuing challenge. Two of these stocks are Pacific sleeper shark (Somniosus pacificus) and Pacific spiny dogfish (Squalus suckleyi). While neither species is targeted commercially in Alaska, both are impacted as incidental catch in longline and trawl fisheries. Due to the rate of bycatch, the acute vulnerability of elasmobranchs due to their extended life history traits, and their ecological importance as predators, a better understanding of population parameters is necessary. The goal of my dissertation is to improve the stock assessments of both species of shark by refining the current abundance models through the incorporation of novel information. To improve the Pacific sleeper shark assessment model, we will further our understanding of the species' life history and movement. 1) I will begin by determining the female length-at-maturity through a meta-analysis of closely related species analyzed in a Bayesian linear framework. 2) I will examine Pacific sleeper shark movement throughout the Bering Sea and Gulf of Alaska utilizing satellite tags and carrying out analysis with hidden Markov movement model. 3) To expand my understanding of the population dynamics of Pacific spiny dogfish I will utilize a broader dataset from the National Marine Fisheries Service database and build a length-based integrated effects model to contrast with the current demographic model. Overall, the refinements to the assessment models of these species will improve my understanding of both stocks' status in Alaskan waters.

• Graduate Student Research Award, North Pacific Research Board
• Northern Gulf of Alaska Applied Research Award, Anonymous Donor
• Research Fellowship, Rasmuson Fisheries Research Center
• Graduate Student Research Assistantship, NOAA Auke Bay Labs