GEOGRAPHICAL VARIATION IN ABUNDANCE OF STRIPED AND COMMON DOLPHINS OFTHE WESTERN MEDITERRANEAN

Citation
J. Forcada et P. Hammond, GEOGRAPHICAL VARIATION IN ABUNDANCE OF STRIPED AND COMMON DOLPHINS OFTHE WESTERN MEDITERRANEAN, Journal of sea research, 39(3-4), 1998, pp. 313-325
Citations number
29
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Oceanografhy,"Marine & Freshwater Biology
Journal title
ISSN journal
1385-1101
Volume
39
Issue
3-4
Year of publication
1998
Pages
313 - 325
Database
ISI
SICI code
1385-1101(1998)39:3-4<313:GVIAOS>2.0.ZU;2-3
Abstract
Line-transect data from sighting surveys conducted in the western Medi terranean (in 1991) and the Alboran Sea (in 1992) were analysed to est imate densities and numbers of striped and common dolphins in various areas of the western Mediterranean. Density of striped dolphins in the northwestern Mediterranean was estimated as 0.20 dolphins km(-2) (CV = 0.24; 95% CI = 0.12 and 0.32) and was 41% higher than in the southwe stern Mediterranean, where it was estimated as 0.12 dolphins km (CV = 0.38; 95% CI = 0.05 and 0.25). The highest densities were observed in the Liguro-Provencal basin, with 0.24 dolphins km(-2) (CV = 0.26; 95% CI = 0.14 and 0.40), and the Alboran Sea, with 0.20 dolphins km(-2) (C V = 0.33; 95% CI = 0.10 and 0.36). These areas, and especially the Lig urian Sea, appear to be the most productive in terms of the food consu med by striped dolphins. Common dolphins were abundant only in the Alb oran Sea with an estimated density of 0.16 dolphins km(-2) (CV = 0.40; 95% CI = 0.08 and 0.35), scarce in the south Balearic area and almost absent in the northwestern Mediterranean. The magnitude of the dolphi n by-catch in fishing operations in the Alboran Sea and other areas st resses the need for further assessment of densities and numbers, notab ly in the Alboran Sea and the North African Mediterranean waters. (C) 1998 Elsevier Science B.V. All rights reserved.