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Behavior of Cape fur seals ( Arctocephalus pusillus pusillus ) in response to spatial variation in white shark ( Carcharodon carcharias ) predation risk
Author(s) -
De Vos Alta,
Justin O'Riain M.,
Meÿer Michael A.,
Kotze P. Gideon. H.,
Kock Alison A.
Publication year - 2015
Publication title -
marine mammal science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.723
H-Index - 78
eISSN - 1748-7692
pISSN - 0824-0469
DOI - 10.1111/mms.12215
Subject(s) - rookery , fur seal , predation , carcharias , foraging , biology , predator , fishery , cape , ecology , sea lion , habitat , geography , population , demography , juvenile , archaeology , sociology
Foraging and predation risk are often separated at rookeries of marine central place foragers, thus offering an opportunity to gain insight into how predator‐avoidance shapes the behavior of prey. Here we compare the behavior of Cape fur seals ( Arctocephalus pusillus pusillus ) at two island rookeries with and without white shark ( Carcharodon carcharias ) predations, and assess seal behavior in relation to marked spatiotemporal variation in risk at the high‐risk site (Seal Island, South Africa). Our results show that seal behavior at the two sites is comparatively similar in summer, when predation risk is low at both sites, but not in winter. Compared to seals at the “low‐risk” site, seals at Seal Island avoided deep‐water habitat around the island at high risk times and restricted their use of this habitat in favor of safe, shallow waters when engaging in social and thermoregulatory behaviors. Seals increased their frequency of jostling, porpoising, and diving when moving through the danger zone and seals in groups were safer than single individuals. Overall, our results suggest that seal behavior around the high‐risk site is strongly affected by predation risk, and show this rookery to be an excellent predator‐prey system at which to evaluate long‐standing ecological hypotheses.