Hostname: page-component-77f85d65b8-6c7dr Total loading time: 0 Render date: 2026-04-18T21:52:17.590Z Has data issue: false hasContentIssue false

The importance of Antarctic toothfish as prey of Weddell seals in the Ross Sea

Published online by Cambridge University Press:  11 May 2009

David G. Ainley*
Affiliation:
HT Harvey & Associates, Los Gatos, CA 95032, USA
Donald B. Siniff
Affiliation:
Department of Ecology, Evolution and Behavioral Biology, University of Minnesota, St Paul, MN 55108, USA

Abstract

Uncertainty exists over the importance of Antarctic toothfish (Dissostichus mawsoni) as prey of top predators in the Ross Sea. In this paper we assess relative weight given to direct, observational evidence of prey taken, as opposed to indirect evidence from scat and biochemical analysis, and conclude that toothfish are important to Weddell seals (Leptonychotes weddellii). The seals eat only the flesh of large toothfish and therefore they are not detected in scat or stomach samples; biochemical samples have been taken from seal sub-populations where toothfish seldom occur. Using direct observations of non-breeding seals away from breeding haulouts in McMurdo Sound, 0.8–1.3 toothfish were taken per day. Based on these and other data, the non-breeding portion of the McMurdo Sound seal population, during spring and summer, consume about 52 tonnes of toothfish. Too many unknowns exist to estimate the non-trivial amount consumed by breeders. We discuss why reduced toothfish availability to Weddell seals, for energetic reasons, cannot be compensated by a switch to silverfish (Pleuragramma antarcticum) or squid. The Ross Sea toothfish fishery should be reduced including greater spatial management, with monitoring of Weddell seal populations by CCAMLR. Otherwise, probable cascades will lead to dramatic changes in the populations of charismatic megafauna.

Information

Type
Review
Copyright
Copyright © Antarctic Science Ltd 2009

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Article purchase

Temporarily unavailable