Dietary analysis of Weddell seals (Leptonychotes weddellii) as concluded from scat collection in McMurdo Sound, Antarctica

Type of content
Theses / Dissertations
Publisher's DOI/URI
Thesis discipline
Science
Degree name
Postgraduate Certificate in Antarctic Studies
Publisher
Journal Title
Journal ISSN
Volume Title
Language
English
Date
2013
Authors
McEldowney, Jessie
Abstract

Weddell seals (Leptonychotes weddellii) in McMurdo Sound have a long history of dietary analyses, with understanding their feeding ecology essential to determining ecological role, trophic links, and prey consumption in the Ross Sea. Twenty-one faecal samples collected in summer 2009 revealed a diet primarily dominated by fish – the tentatively identified nototheniid Pleuragramma antarcticum in particular – with over 83% of samples exhibiting some evidence of piscines. Despite this, often a large percentage of samples will not contain identifiable otoliths, and as such no direct confirmation for the believed major prey item Antarctic toothfish (Dissostichus mawsoni) consumption was exhibited, especially with the tendency for Weddell seals to avoid eating the head, skin, and vertebral column. The excessive presence of plankton (in 100% of samples) has led to supporting the proposal of secondary ingestion, and similar theories have been applied to the occurrence of rocks and stones (in over 16% of samples). With all this uncertainty, the future of dietary analysis in Weddell seals is moving away from taxonomic identification of faecal hard parts, and more towards molecular methods such as DNA and stable isotope analysis, as combined methods tend to have a greater success rate than singular identification techniques.

Description
Citation
Keywords
Ngā upoko tukutuku/Māori subject headings
ANZSRC fields of research
Rights
All Rights Reserved