Thursday
January 11, 2007
4:30-5:30 pm
102 Fishery Sciences
(auditorium)
Social follows talk
Thursday
January 11, 2007
4:30-5:30 pm
102 Fishery Sciences
(auditorium)
Social follows talk
Professor, School of Fisheries and Ocean Sciences, University of Alaska Juneau
For more than three decades, population abundances and commercial catches of Alaskan crab stocks fluctuated widely, driven by highly variable recruitment. For most stocks, recent abundances are very low compared to historical levels. We sought to better understand recruitment variation of six stocks of red king (Paralithodes camtschaticus), blue king (P. platypus), Tanner (Chionoecetes bairdi), and snow (C. opilio) crabs in the eastern Bering Sea (EBS). Most crab recruitment time series are not significantly correlated with each other. Spatial distributions of three broadly distributed crab stocks (EBS snow and Tanner crabs and Bristol Bay red king crab) changed considerably over time, possibly related to shifts in regional climate and physical oceanography. Three climate forcing hypotheses on larval survival were proposed to explain crab recruitment variation of Bristol Bay red king crab and EBS Tanner and snow crabs. Some empirical evidence suggests that groundfish predation may play an important role in crab recruitment success. Environmental changes have caused major shifts in abundance and spatial distributions of groundfish predators, as well. Although many of the mechanisms affecting crab recruitment remain speculative, it appears likely that changes in climate and oceanography associated with global warming will adversely affect Alaskan crab stocks into the future. Comprehensive field are needed to test our hypotheses and spatially explicit modeling studies will further our understanding of the relative importance and synergistic effects of bottom-up and top-down controls on crab recruitment.
Gordon Kruse is a Professor of Fisheries with the School of Fisheries and Ocean Sciences, University of Alaska Fairbanks. Gordon is also the chair of the Scientific and Statistical Committee of the North Pacific Fishery Management Council and the Chair of the Fishery Science Committee for the North Pacific Marine Science Organization (PICES). With 17 years of experience in the marine fisheries of Alaska, his research draws broadly from a diverse background in stock assessment, population modeling, fisheries oceanography, management strategies, bycatch reduction methods, and other applied fisheries research. Previously, Gordon was the chief marine fisheries scientist for the Alaska Department of Fish and Game, developing the state’s marine fish and invertebrate stock assessment and research programs. He participated in National Academy of Sciences studies on “Effects of trawling and dredging on seafloor habitat” and the “Alaska Groundfish Fishery and Steller Sea Lions". Gordon earned his Ph.D. in fisheries at Oregon State University (1983) and has published 58 peer-reviewed papers focusing on stock assessment, population dynamics, and the management of crabs, other invertebrates, and flatfish.