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Past Shellfish Assessment (Kodiak) Research

Climate Change Impacts on Distribution of Species in the Bering Sea
Mike Litzow is working with Franz Mueter (Sigma-Plus Consulting) to see how warming of the Bering Sea has changed the distribution of fish and invertebrates over the last few decades, using trawl survey data from 1979-2005 to do a community-wide analysis, looking at every taxon that has been consistently identified to the species level. They are also looking at the potential for changes in trophic interactions, the relationship between predators and prey. Presented Warming Climate Alters the Biogeography of the Southern Bering Sea at the 2007 Alaska Marine Science Symposia in Anchorage, Alaska.

Essential fatty acids, Climate Change, and Fish Communities
This project, conducted by Mike Litzow in collaboration with scientists from the Alaska Fisheries Science Center’s Fisheries-Oceanography Coordinated Investigation and Auke Bay Lab, and the University of Oregon, sought to determine whether-climate-forced changes in the production of polyunsaturated fatty acids by phytoplankton might contribute to reorganizations of fish communities. See: LITZOW, M. A., K. M. BAILEY, F. G. PRAHL, and R. A. HEINTZ. 2006. Climate regime shifts and reorganization of fish communities: the essential fatty acid limitation hypothesis. (Mar. Ecol. Prog. Ser. 315:1-11., .pdf, 374KB).

An Ecological History of Alaskan Fisheries
This project, conducted by Mike Litzow in collaboration with Dan Urban from the Alaska Department of Fish and Game, uses a history of commercial fishery catches in Alaska from 1893 to 2004 to better understand the ecosystem effects of fishing and climate change. The abstract from the AFSC Seminar series talk, Fishing Down (and up) Alaskan Food Webs, offers more information on this project.

Role of Climate Regulation in Top-Down and Bottom-up Ecosystem Control of Forage Species Community Structure in the Gulf of Alaska
Mike Litzow in collaboration Lorenzo Ciannelli (Oregon State University), analyzed observed changes in forage species catch composition from a small-mesh trawl survey conducted from 1972-2005 to study the impacts of ocean warming on predator-prey interactions and their implications of these impacts across the wider marine community structure in the Gulf of Alaska.

EFH for Blue King Crab, Paralithodes platypus: Development of Larval Cultivation Techniques
Under the guidance of Dr. Bradley Stevens, the ultimate goal of this three year study, partially funded by a North Pacific Research Board 2003 grant, is to understand the relationship between Essential Fish Habitat (EFH) for “overfished” Pribilof Islands blue king crab (link to photos) and survival in the first year of life. The first year, Sara Persselin and Julie Matweyou, developed techniques for cultivation of blue king crab larvae, verified the ability to raise them in the laboratory, and determined the optimum conditions for cultivation. Subsequent years work focused on settlement behavior and habitat selection, survival of larval and juvenile blue king crab, and competitive interactions with juvenile red king crab. From this work several posters and papers have been presented so far:

Size of Maturity of Dungeness Crab in the Kodiak Area
Katherine Swiney (NMFS), Dan Urban (ADF&G) and Carrie Worton (ADF&G) are collaborating on a multi-year project to determine the size of maturity of Dungeness crab (Cancer magister) in Kodiak. Beginning in 2002 male Dungeness crab were collected to determine the size of physiological maturity (that size in which males produce spermatophores). In 2003 mating studies will be conducted in the laboratory to determine at which size males can successfully mate with females (functional maturity).

Reproductive Dynamics and Life-History of Snow Crab in Eastern Bering Sea
In 2002, Principal Investigators, Dr.Louis Rugolo  (NMFS) and Douglas Pengilly (ADFG) and Co-Investigators, Richard MacIntosh (retired), and Kirsten Gavel (ADFG) began this extensive seasonal study of snow crab in the EBS. Their project goals are many: to understand the female reproductive cycle and reproductive dynamics; assess female snow crab reproductive health; to improve the understanding of the female seasonal reproductive cycle (mating to extrusion to hatching); standardize clutch fullness scoring; to characterize seasonal timing of male molting via pre-molt and molt-stage indicators; the role of male population size structure and year class strength on female reproductive success; and to derive male and female maturity schedules. This project is funded by NOAA under the Bering Sea Snow Crab Fishery Restoration Research grant administered by the Alaska Department of Fish and Game.

Gulf of Alaska Seamounts Exploration of Deepwater Crab
Kodiak staff and Dr. Bradley Stevens has participated in two ventures so far using the Deep Submergence Vehicle (DSV) Alvin to explore seamounts in the Gulf of Alaska. The first was a 1999 exploration of the Patton Seamount to investigate the depth distribution of several deepwater crab species. Dr. Stevens revisited the Patton seamount, as well as the Murray seamount, when he joined the crew of the R/V Atlantis during the 2002 Gulf of Alaska Seamounts Expedition, where seven seamounts (five of which were previously unexplored) were visited. Funding was provided by the NOAA Office of Exploration and the West Coast & Polar Regions Undersea Research Center.

For a comprehensive list of Alaskan crab species, refer to the Checklist of Alaskan crabs (44 kb .pdf file), p.5-8. In: A.J. Paul, et al. (editors), Crabs in Cold Water Regions: Biology, Management, and Economics. Alaska Sea Grant College Program, University of Alaska Fairbanks, AK-SG-02-01.

Tanner Crab Reproductive Behavior
Since 1991, Dr. Bradley Stevens and Kodiak staff have used Remotely Operated Vehicles (ROV) and benthic camera sleds to conduct detailed studies of Tanner crab reproductive behavior in Chiniak Bay off Kodiak Island. The research began when Dr. Stevens discovered a vast aggregation of Tanner crab mounds while exploring the Chiniak Bay region in the DSV Delta. Recent efforts have been focused on determining the relationship between time of mound formation in the wild, larval release by crabs in the laboratory, and environmental changes, particularly tidal fluctuations. This research is conducted in association with - and with support from - the Alaska Department of Fish and Game (ADFG) and the West Coast National Undersea Research Program (NURP).

Crab Dietary Studies
Live foods for crabs are difficult to maintain, and frozen foods often are not nutritionally complete. Long term feeding with frozen fish and squid result in loss of color and difficulties in molting. Dr. Bradley Stevens and Kermit Reppond (REUT Div, NWFSC) have conducted studies to determine if survival of juvenile king crabs can be improved using artificial diets, as well as additional studies on food attractiveness and feeding rates.

Long-term Changes in the Gulf of Alaska Small Mesh Trawl Survey, 1953-1998 (poster 628KB pdf)
Linkage of species community structure to climatic changes on decadal scales in the Gulf of Alaska is investigated with analysis of long-term fishery survey data collected continuously since 1953. Since 1995, Principal Investigators, Paul Anderson(formally of NMFS), John Piatt (U.S. Department of Interior-USGS-Biological Research Division), William Bechtol(ADFG), and Jim Blackburn (ADF&G) have assembled and analyzed data from small-mesh trawl surveys in the GOA from Kayak Island to Unimak Pass to describe long-term (1953-1998) changes in species abundance and distribution. Small-mesh trawl sampling has proved useful in describing changes in forage species abundance not well sampled by larger mesh trawls used in regular assessment surveys of the GOA. Much of this research was funded by grants from the EXXON VALDEZ Oil Spill Trustee Council and the Steller Sea Lion Research funds. This project utilized matching funding from cooperators US DOI/USGS BRD, and ADF&G (Kodiak), as well as NMFS. Contact Mike Litzow for further information.

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