MEPS 484:259-277 (2013)  -  DOI: https://doi.org/10.3354/meps10347

Modeled distribution and abundance of a pelagic seabird reveal trends in relation to fisheries

Martin Renner1,5,*, Julia K. Parrish1, John F. Piatt2, Kathy J. Kuletz3, Ann E. Edwards1,4, George L. Hunt Jr.

1School of Aquatic and Fishery Sciences, University of Washington, Box 351800, Seattle Washington 98195, USA
2US Geological Survey, Alaska Science Center, 4210 University Drive, Anchorage, Alaska 99508, USA
3Migratory Bird Management, US Fish and Wildlife Service, 1011 E. Tudor Rd., Anchorage, Alaska 99503, USA
4Alaska Fisheries Science Center, NOAA, REFM Division, 7600 Sand Point Way NE, Seattle, Washington 98115, USA
5Present address: Tern Again Consulting, 388 E. Bayview Ave., Homer, Alaska 99603, USA

ABSTRACT: The northern fulmar Fulmarus glacialis is one of the most visible and widespread seabirds in the eastern Bering Sea and Aleutian Islands. However, relatively little is known about its abundance, trends, or the factors that shape its distribution. We used a long-term pelagic dataset to model changes in fulmar at-sea distribution and abundance since the mid-1970s. We used an ensemble model, based on a weighted average of generalized additive model (GAM), multivariate adaptive regression splines (MARS), and random forest models to estimate the pelagic distribution and density of fulmars in the waters of the Aleutian Archipelago and Bering Sea. The most important predictor variables were colony effect, sea surface temperature, distribution of fisheries, location, and primary productivity. We calculated a time series from the ratio of observed to predicted values and found that fulmar at-sea abundance declined from the 1970s to the 2000s at a rate of 0.83% (± 0.39% SE) per annum. Interpolating fulmar densities on a spatial grid through time, we found that the center of fulmar distribution in the Bering Sea has shifted north, coinciding with a northward shift in fish catches and a warming ocean. Our study shows that fisheries are an important, but not the only factor, shaping fulmar distribution and abundance trends in the eastern Bering Sea and Aleutian Islands.


KEY WORDS: Aleutian Islands · Bering Sea · Distribution shifts · Fisheries · Fulmarus glacialis · Habitat modeling · Population trend


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Cite this article as: Renner M, Parrish JK, Piatt JF, Kuletz KJ, Edwards AE, Hunt GL Jr (2013) Modeled distribution and abundance of a pelagic seabird reveal trends in relation to fisheries. Mar Ecol Prog Ser 484:259-277. https://doi.org/10.3354/meps10347

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