tailieunhanh - Species and stock identification of prey consumed by endangered southern resident killer whales in their summer range

Intuitively, the state of the business cycle can influence bank equity prices through its impact on bank assets. During an economic boom, default rates for loans to households and firms decline. This, in turn, boosts bank earnings and can mitigate investors’ perception of the risk in bank profits, thereby lowering their required return on bank stocks. Recessions have the opposite impact on loan values and bank earnings, thereby raising required returns. In fact, the impact is arguably asymmetric. The negative influence near the bottom of the cycle is stronger than the positive influence near the top of the cycle, given. | Vol. 11 69-82 2010 doi esr00263 ENDANGERED SPECIES RESEARCH Endang Species Res Published online March 11 OPEN ACCESS Species and stock identification of prey consumed by endangered southern resident killer whales in their summer range M. Bradley Hanson1 Robin W. Baird2 John K. B. Ford3 Jennifer Hempelmann-Halos1 Donald M. Van Doornik4 John R. Candy3 Candice K. Emmons1 Gregory S. Schorr 2 Brian Gisborne3 Katherine L. Ayres5 Samuel K. Wasser5 Kenneth C. Balcomb6 Kelley Balcomb-Bartok6 8 John G. Sneva7 Michael J. Ford1 1National Marine Fisheries Service Northwest Fisheries Science Center Seattle Washington 98112 USA 2Cascadia Research Collective Olympia Washington 98501 USA 3Fisheries and Oceans Canada Pacific Biological Station Nanaimo British Columbia V9T 6N7 Canada 4Northwest Fisheries Science Center Manchester Research Station Manchester Washington 98353 USA 5University of Washington Center for Conservation Biology Department of Biology Seattle Washington 98195 USA 6Center for Whale Research Friday Harbor Washington 98250 USA Washington Department of Fish and Wildlife Olympia Washington 98501 USA Presentaddress Renton City Hall Renton Washington 98057 USA ABSTRACT Recovery plans for endangered southern resident killer whales Orcinus orca have identified reduced prey availability as a risk to the population. In order to better assess this risk we studied prey selection from 2004 to 2008 in 2 regions of the whales summer range San Juan Islands Washington and the western Strait of Juan de Fuca British Columbia. Following the whales in a small boat we collected fish scales and tissue remains from predation events and feces using a fine mesh net. Visual fish scale analysis and molecular genetic methods were used to identify the species consumed. Chinook salmon a relatively rare species was by far the most frequent prey item confirming previous studies. For Chinook salmon prey we used genetic identification methods to estimate the spawning region of origin. Of .