PREY SELECTION BY HARBOR SEALS, PHOCA-VITULINA, IN RELATION TO VARIATIONS IN PREY ABUNDANCE

Citation
Dj. Tollit et al., PREY SELECTION BY HARBOR SEALS, PHOCA-VITULINA, IN RELATION TO VARIATIONS IN PREY ABUNDANCE, Canadian journal of zoology, 75(9), 1997, pp. 1508-1518
Citations number
48
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Zoology
Journal title
ISSN journal
0008-4301
Volume
75
Issue
9
Year of publication
1997
Pages
1508 - 1518
Database
ISI
SICI code
0008-4301(1997)75:9<1508:PSBHSP>2.0.ZU;2-O
Abstract
This study compared the composition of the diet of harbour seals (Phoc a vitulina) feeding in the Moray Firth, Scotland, with the abundance o f their fish prey estimated from dedicated fishery surveys in January 1992 and 1994 and June 1992. Prey-size selection was also examined in these three time periods and in January 1991. In each period, the most abundant fish species contributed most to the diet. However, the rela tive abundances of the remaining species in the sea showed little simi larity to their contribution to the seals' diet. Diet composition was almost totally dominated by either pelagic species or species dwelling on or strongly associated with the seabed, depending upon the relativ e abundance of pelagic schooling prey. Most fish consumed were 10-16 c m in length, although larger cod and herring were taken. With the exce ption of cod, the extent of size selection was dependent upon the use of correction factors that accounted for otolith erosion due to digest ion.