A Comparison of the Eastern Bering and Western Bering Sea Shelf and Slope Ecosystems Through the Use of Mass-Balance Food Web Models

A comparison of the food webs of the eastern and western Bering Sea continental shelf large marine ecosystems (EBS and WBS LMEs) is presented, with a literature review of Russian and English sources for the western Bering Sea food web. A model is constructed using Ecopath, a tool for performing quantitative mass-balance calculations to synthesize food web data. The model focuses on the earliest period for which detailed diet data was available in both systems, 1980-85. The results show that the broad EBS shelf supports a benthic community of considerable diversity, while the narrower WBS shelf contains an ecosystem with a higher per-unit-area production in the pelagic layers and a more productive pelagic phytoplankton and zooplankton community. Keystone species in both systems are walleye pollock (Theragra chalcogramma) and Pacific cod (Gadus macrocephalus). In the eastern Bering Sea, small flatfish and crab species have a large impact on the energy flow from the benthic web to upper trophic levels. On the other hand, in the WBS, a large proportion of detritus entering the benthic food web is consumed by epifaunal species such as urchins and brittlestars. This may be due to the larger percentage of WBS shelf area close to shore. Additional measures of ecosystem structure, maturity, and sensitivity are presented. Future steps in pursuing ecosystem modeling efforts through the food webs in these two systems should lie in determining the importance and role of deep Bering Sea Basin processes, especially through mesopelagic forage fish, and in further subpartitioning each model into fine scale biophysical domains.

[1]  F. Favorite.  Oceanography of the subarctic Pacific region, 1960-71 , 1976 .

[2]  K. Piner,et al.  The 1999 Northwest Fisheries Science Center Pacific west coast upper continental slope trawl survey of groundfish resources off Washington, Oregon, and California : estimates of distribution, abundance, and length composition , 2001 .

[3]  D. S. Jordan.  THE FUR SEALS. , 1920, Science.

[4]  Christopher D. Wilson,et al.  Echo integration-trawl survey of Pacific hake, Merluccius productus, off the Pacific coast of the United States and Canada during June-August, 2001 , 2003 .

[5]  M. Terazaki.  Life history, distribution, seasonal variability and feeding of the pelagic chaetognath Sagitta elegans in the Subarctic Pacific : A review , 1998 .

[6]  B. Coleman.  The 1980 Pacific west coast bottom trawl survey of groundfish resources : estimates of distribution, abundance, length and age composition , 1986 .

[7]  KERIM AYDIN,et al.  The early development of Ecosim as a predictive multi-species fisheries management tool , 2002 .

[8]  J. H. Fraser.  Experimental Feeding of Some Medusae and Chaetognatha , 1969 .

[9]  Alan M. Springer,et al.  The Bering Sea Green Belt: shelf-edge processes and ecosystem production , 1996 .

[10]  J. W. Orr,et al.  Guide to Rockfishes (Scorpaenidae) of the Genera Sebastes, Sebastolobus, and Adelosebastes of the Northeast Pacific Ocean, Second Edition , 1998 .

[11]  H. Heessen.  Variability and management of large marine ecosystems , 1989 .

[12]  H. Asmus.  Secondary production of an intertidal mussel bed community related to its storage and turnover compartments , 1987 .

[13]  W. Marquette.  Annotated Bibliography of the Bowhead Whale, Balaena mysticetus, 1767-1983 , 2002 .

[14]  F. Armstrong,et al.  Chemical Oceanography , 1959, Nature.

[15]  T. Loughlin,et al.  Aerial and Land-Based Surveys of Steller Sea Lions (Eumetopias jubatus) , 1999 .

[16]  James D. Schumacher,et al.  The Physical Oceanography of the Bering Sea , 1999 .

[17]  Y. Sorokin.  Data on primary production in the Bering Sea and adjacent Northern Pacific , 1999 .

[18]  R. Warwick,et al.  Macrofauna production in an estuarine mud-flat , 1975, Journal of the Marine Biological Association of the United Kingdom.

[19]  Villy Christensen,et al.  ECOPATH II − a software for balancing steady-state ecosystem models and calculating network characteristics , 1992 .

[20]  Richard C. Ferrero,et al.  Steller Sea Lion Research and Coordination: A Brief History and Summary of Recent Progress , 2002 .

[21]  J. Wallace,et al.  The 2001 U.S. West Coast upper continental slope trawl survey of groundfish resources off Washington, Oregon, and California : estimates of distribution, abundance, and length composition , 2005 .

[22]  V. V. Lapko,et al.  New data about communities of plankton and nekton of the far‐eastern seas in connection with climate‐oceanological reorganization , 1996 .

[23]  Hood.  Processes and resources of the Bering Sea shelf (PROBES) , 1985 .

[24]  M. Sheader,et al.  Feeding and gut structure of Parathemisto gaudichaudi (Guerin) (Amphipoda, Hyperiidea) , 1975, Journal of the Marine Biological Association of the United Kingdom.

[25]  Patricia A. Livingston,et al.  Ecosystem Change and the Decline of Marine Mammals in the Eastern Bering Sea : Testing the Ecosystem Shift and Commercial Whaling Hypotheses , 1999 .

[26]  D. A. Wion,et al.  Mobile Fishing Gear Effects on Benthic Habitats: A Bibliography (Second Edition) , 2000 .

[27]  D. Clausen,et al.  Data report : 1990 Gulf of Alaska bottom trawl survey , 1995 .

[28]  D. McLusky,et al.  Population dynamics of oligochaetes and small polychaetes in the polluted forth estury ecosystem , 1982 .

[29]  D. Schneider,et al.  The trophic organization of the marine bird community in the Bering Sea , 1993 .

[30]  K. Ohtani.  Oceanographic Structure in the Bering Sea , 1973 .

[31]  U. Båmstedt.  Trophodynamics of the scyphomedusae Aurelia aurita . Predation rate in relation to abundance, size and type of prey organism , 1990 .

[32]  Y. Tkachenko,et al.  Recent observations of variability in the western Bering Sea current system , 1992 .

[33]  Carl J. Walters,et al.  Ecopath, Ecosim, and Ecospace as tools for evaluating ecosystem impact of fisheries , 2000 .

[34]  K. Banse,et al.  Adult Body Mass and Annual Production/Biomass Relationships of Field Populations , 1980 .