Marine predators and persistent prey in the southeast Bering Sea

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• 作者：Michael F. Sigler^a ; ^{Mike.Sigler@noaa.gov} ; Kathy J. Kuletz^b ; ^{Kathy_Kuletz@fws.gov} ; Patrick H. Ressler^c ; ^{Patrick.Ressler@noaa.gov} ; Nancy A. Friday^c ; ^{Nancy.Friday@noaa.gov} ; Christopher D. Wilson^c ; ^{Chris.Wilson@noaa.gov} ; Alexandre N. Zerbini^c ; ^{Alex.Zerbini@noaa.gov}
• 关键词：Seabirds ; Whales ; Prey ; Persistence ; Hot spots
• 刊名：Deep Sea Research Part II ; Topical Studies in Oceanography
• 出版年：2012
• 期刊代码：20_09670645
• 类别：ear
• 出版时间：15 June, 2012
• 卷：65-70
• 期：Complete
• 页码：292-303
• 文件大小：1866 K

摘要

Predictable prey locations reduce search time and energetic costs of foraging; thus marine predators often exploit locations where prey concentrations persist. In our study, we examined whether this association is influenced by differences among predator species in foraging modes (travel cost, surface feeder or diver) or whether the predator species is a central place forager or not. We examined distributions of two seabird species during their nesting period, the surface-feeding black-legged kittiwake (Rissa tridactyla) and the pursuit-diving thick-billed murre (Uria lomvia), and two baleen whale species, the humpback whale (Megaptera novaeangliae) and the fin whale (Balaenoptera physalus), in relation to two key prey, age-1 walleye pollock (Theragra chalcogramma) and euphausiids (Euphausiidae). Prey surveys were conducted once each year during 2004 and 2006-2010. Concurrent predator surveys were conducted in 2006-2010 (seabirds) and 2008 and 2010 (whales). We compared the seabird and whale foraging locations to where age-1 pollock and euphausiids were concentrated and considered the persistence of these concentrations, where the time-scale of persistence is year (i.e., a comparison among surveys that are conducted once each year). Euphausiids were widespread and concentrations often were reliably found within specific 37 km脳37 km blocks (鈥榩ersistent hot spots of prey鈥?. In contrast, age-1 pollock were more concentrated and their hot spots were persistent only on coarser scales (>37 km). Both seabird species, regardless of foraging mode, were associated with age-1 pollock but not with euphausiids, even though age-1 pollock were less persistent than euphausiids. The higher travel cost central place foragers, thick-billed murres, foraged at prey concentrations nearer their island colonies than black-legged kittiwakes, which were more widespread foragers. Humpback whales were not tied to a central place and mostly were located only where euphausiids were concentrated, and further, often in locations where these concentrations were persistent. Fin whales were associated with locations where age-1 pollock were more likely, similar to black-legged kittiwakes and thick-billed murres, but their association with euphausiids was unclear. Our results suggest that a predator's foraging mode and their restrictions during breeding affect their response to prey persistence.