Influence of hunting strategy on foraging efficiency in Galapagos sea lions

PeerJ

article

Jessica-Anne Blakeway¹  John P.Y. Arnould¹  Andrew J. Hoskins²  Patricia Martin-Cabrera¹  Grace J. Sutton¹  Luis A. Huckstadt³  Daniel P. Costa³  Diego Páez-Rosas⁴  Stella Villegas-Amtmann³ 

[1] School of Life and Environmental Sciences, Deakin University;CSIRO Health and Biosecurity;Department of Ecology & Evolutionary Biology, University of California;Universidad San Francisco de Quito and Galapagos Science Center;Dirección Parque Nacional Galápagos

关键词: Telemetry;    Pinniped;    Zalophus wollebaeki;    Dive behaviour;    Galapagos Islands;    Accelerometers;    Feeding;   

DOI  :  10.7717/peerj.11206

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

The endangered Galapagos sea lion (GSL, Zalophus wollebaeki) exhibits a range of foraging strategies utilising various dive types including benthic, epipelagic and mesopelagic dives. In the present study, potential prey captures (PPC), prey energy consumption and energy expenditure in lactating adult female GSLs (n = 9) were examined to determine their foraging efficiency relative to the foraging strategy used. Individuals displayed four dive types: (a) epipelagic (100 m; MP) with a characteristic V-shape or U-shape diving profile; and (c) shallow benthic (100 m; DB) with square or flat-bottom dive profiles. These dive types varied in the number of PPC, assumed prey types, and the energy expended. Prey items and their energetic value were assumed from previous GSL diet studies in combination with common habitat and depth ranges of the prey. In comparison to pelagic dives occurring at similar depths, when diving benthically, GSLs had both higher prey energy consumption and foraging energy expenditure whereas PPC rate was lower. Foraging efficiency varied across dive types, with benthic dives being more profitable than pelagic dives. Three foraging trip strategies were identified and varied relative to prey energy consumed, energy expended, and dive behaviour. Foraging efficiency did not significantly vary among the foraging trip strategies suggesting that, while individuals may diverge into different foraging habitats, they are optimal within them. These findings indicate that these three strategies will have different sensitivities to habitat-specific fluctuations due to environmental change.

【 授权许可】

CC BY