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Influence of hunting strategy on foraging efficiency in Galapagos sea lions
Blakeway, J.-A.; Arnould, J.P.Y.; Hoskins, A.J.; Martin-Cabrera, P.; Sutton, G.J.; Hückstädt, L.A.; Costa, D.P.; Páez-Rosas, D.; Villegas-Amtmann, S. (2021). Influence of hunting strategy on foraging efficiency in Galapagos sea lions. PeerJ 9: e11206. https://dx.doi.org/10.7717/peerj.11206
In: PeerJ. PeerJ: Corte Madera & London. ISSN 2167-8359, more
Peer reviewed article  

Available in  Authors 

Keywords
    Zalophus wollebaeki Sivertsen, 1953 [WoRMS]
    Marine/Coastal
Author keywords
    Telemetry, Pinniped, Zalophus wollebaeki, Dive behaviour, Galapagos Islands, Accelerometers, Feeding

Authors  Top 
  • Blakeway, J.-A.
  • Arnould, J.P.Y.
  • Hoskins, A.J.
  • Martin-Cabrera, P., more
  • Sutton, G.J.
  • Hückstädt, L.A.
  • Costa, D.P.
  • Páez-Rosas, D.
  • Villegas-Amtmann, S.

Abstract
    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; EP); or (b) mesopelagic (>100 m; MP) with a characteristic V-shape or U-shape diving profile; and (c) shallow benthic (<100 m; SB) or (d) deep 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.

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