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Inferring diet, feeding behaviour and causes of mortality from prey-induced injuries in a New Zealand fur seal


Hocking, DP and Marx, FG and Parker, WMG and Rule, JP and Cleuren, SGC and Mitchell, AD and Hunter, M and Bell, JD and Fitzgerald, EMG and Evans, AR, Inferring diet, feeding behaviour and causes of mortality from prey-induced injuries in a New Zealand fur seal, Diseases of Aquatic Organisms, 139 pp. 81-86. ISSN 0177-5103 (2020) [Refereed Article]

Available from 01 May 2025

Copyright Statement

Copyright 2020 Inter-Research

DOI: doi:10.3354/dao03473


ABSTRACT: New Zealand fur seals Arctocephalus forsteri are the most abundant of the 4 otariid (eared seal) species distributed across Australasia. Analyses of stomach contents, scats and regurgitates suggest a diet dominated by bony fish and squid, with cartilaginous species (e.g. sharks and rays) either absent or underrepresented because of a lack of preservable hard parts. Here we report on a subadult specimen from south-eastern Australia, which was found ashore emaciated and with numerous puncture wounds across its lips, cheeks, throat and the inside of its oral cavity. Fish spines embedded in the carcass revealed that these injuries were inflicted by chimaeras and myliobatiform rays (stingrays and relatives), which matches reports on the diet of A. forsteri from New Zealand, but not South Australia. Shaking and tearing of prey at the surface may help to avoid ingestion of the venomous spines, perhaps contributing to their absence from scats and regurgitates. Nevertheless, the number and severity of the facial stab wounds, some of which led to local necrosis, likely affected the animalís ability to feed, and may account for its death. Despite their detrimental effects, fish spine-related injuries are difficult to spot, and may be a common, albeit cryptic, type of trauma. We therefore recommend that stranded seals be systematically examined for this potentially life-threatening pathology.

Item Details

Item Type:Refereed Article
Keywords:Arctocephalus forsteri, elephant fish, stingray, injury, pinniped, prey processing
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Behavioural ecology
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the biological sciences
UTAS Author:Bell, JD (Dr Justin Bell)
ID Code:143582
Year Published:2020
Web of Science® Times Cited:1
Deposited By:Ecology and Biodiversity
Deposited On:2021-03-25
Last Modified:2021-04-12

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