Geographical patterns of seabird attendance to a research trawler along the Iberian Mediterranean coast

Pere Abelló,José Manuel Arcos,Luis Gil Sola

doi:10.3989/scimar.2003.67s269

Abstract

SUMMARY: The attendance of seabirds to a research trawler along the Mediterranean coast of the Iberian Peninsula was monitored during six demersal surveys (MEDITS project). Cruises were performed in late spring during the period 19941999. Twenty seabird species were recorded, including both breeders and migrants. The four most common species behind the boat were local breeders, namely the Balearic shearwater Puffinus mauretanicus, Cory’s shearwater Calonectris diomedea, Audouin’s gull Larus audouinii and the yellow-legged gull Larus cachinnans. Most seabirds made use of trawler discards to some extent, with the exception of the Puffin Fratercula arctica. Geographically consistent patterns were identified in the six years surveyed. Seabirds were most abundant along the eastern coast of Iberia, especially off the Ebro Delta and around the Columbretes Islands, coinciding with one of the major areas of primary productivity and one of the largest trawling fleets in the western Mediterranean. The location of the main seabird colonies also influenced the distribution of breeders.

Highlights

Mediterranean seabirds are known mainly through land-based field studies, and information from data gathered at sea is very scarce and valuable (e.g. Abelló and Oro, 1998; Conejero and Beaubrun, 1998; Beaubrun et al, 2000). some information concerning the ecology of seabirds at sea can be inferred from studies at colonies, it is important to complement these approaches with information collected directly at sea
SUMMARY: The attendance of seabirds to a research trawler along the Mediterranean coast of the Iberian Peninsula was monitored during six demersal surveys (MEDITS project)
Seabirds were most abundant along the eastern coast of Iberia, especially off the Ebro Delta and around the Columbretes Islands, coinciding with one of the major areas of primary productivity and one of the largest trawling fleets in the western Mediterranean

Summary

Introduction

Mediterranean seabirds are known mainly through land-based field studies, and information from data gathered at sea is very scarce and valuable (e.g. Abelló and Oro, 1998; Conejero and Beaubrun, 1998; Beaubrun et al, 2000). some information concerning the ecology of seabirds at sea can be inferred from studies at colonies (e.g. through examining diets and activity patterns), it is important to complement these approaches with information collected directly at sea. Despite the relatively low productivity of the Mediterranean (Estrada et al, 1985; Estrada, 1996), there is a diverse community of breeding seabirds, with some species and subspecies endemic to the area. These features, combined with limited population sizes, make the Mediterranean basin an important zone for seabird conservation (Zotier et al., 1999). In this respect, it is important to document the distribution of different seabird species at sea, as well as to identify their key food resources.

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Discussion

Conclusion