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ENVIRONMENTAL FACTORS INFLUENCING THE DISTRIBUTION OF SOUTHERN RIGHT WHALES ( EUBALAENA AUSTRALIS ) ON THE SOUTH COAST OF SOUTH AFRICA I: BROAD SCALE PATTERNS

Simon H. Elwen; Peter B. Best
Marine Mammal Science · Vol. 20, Issue 3 · pp. 567-582 · 2004

Abstract

A bstract Aerial surveys over the last 32 yr have shown that the distribution of southern right whales Eubalaena australis along the south coast of South Africa is markedly discontinuous, but highly predictable. A GIS was used at a variety of scales to investigate whether this pattern was related to environmental characteristics. Whale distribution was analyzed as density per 20‐min bin of longitude over two temporal and spatial scales, namely 15 bins for 32 yr, and a wider scale but shorter time period, 23 bins for 19 yr, as well as using three years of GPS accuracy data (15 bins) for finer scale analysis. Environmental factors tested were depth, distance from shore, sea floor slope, protection from swell, protection from wind, and shore type. The majority of whales were concentrated in areas that provided reasonable protection from open ocean swell and seasonal winds, and had sedimentary floors with gentle slopes. They generally avoided exposed rocky shorelines. Cow‐calf pairs were found significantly closer to shore and in shallower water than unaccompanied whales, particularly off sandy beaches. Habitat choice at this time of year may be related both to energy conservation for calves and lactating females (calm sea conditions) and to protection of the new‐born.

Bibliographic Information

JournalMarine Mammal Science
PublisherWiley
Publication Date2004-07-01
Publication Year2004
Volume20
Issue3
Pages567-582
Document TypeJournal Article
Print ISSN0824-0469
eISSN1748-7692
DOI10.1111/j.1748-7692.2004.tb01180.x
SubjectMarine Biology

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NARA Access Coverage1997-01-01~Current
Journal Homepagehttps://onlinelibrary.wiley.com/loi/17487692
Publisher PageOpen Publisher Page
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