Consumption choice by bears feeding on salmon

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• 作者：S. M. Gende ; T. P. Quinn and M. F. Willson
• 刊名：Oecologia
• 出版年：2001
• 出版时间：May 2001
• 年：2001
• 卷：127
• 期：3
• 页码：372-382
• 全文大小：110 KB
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Life Sciences
  Ecology
  Plant Sciences
  
• 出版者：Springer Berlin / Heidelberg
• ISSN：1432-1939

文摘

Consumption choice by brown (Ursus arctos) and black bears (U. americanus) feeding on salmon was recorded for over 20,000 bear-killed fish from 1994 to 1999 in Bristol Bay (sockeye salmon, Oncorhynchus nerka) and southeastern Alaska (pink, O. gorbuscha and chum salmon O. keta). These data revealed striking patterns of partial and selective consumption that varied with relative availability and attributes of the fish. As the availability of salmon decreased, bears consumed a larger proportion of each fish among both years and habitats. When availability was high (absolute number and density of salmon), bears consumed less biomass per captured fish, targeting energy-rich fish (those that had not spawned) or energy-rich body parts (eggs in females; brain in males). In contrast, individual fish were consumed to a much greater extent, regardless of sex or spawning status, in habitats or years of low salmon availability. The proportion of biomass consumed per fish was similar for males and females, when spawning status was statistically controlled, but bears targeted different body parts: the body flesh, brain and dorsal hump in males and the roe in females. Bears thus appeared to maximize energy intake by modifying the amount and body parts consumed, based on availability and attributes of spawning salmon.