Abstract:

This paper presents baseline data concerning the year round status and distribution of shearwater (Procellariforme) species in the Bay of Biscay and western English Channel from a preliminary analysis of sightings data collected through Biscay Dolphin Research Programme (BDRP) surveys between September 1995 and February 2001. Six species of shearwater were recorded in the Bay of Biscay through BDRP surveys; Cory s Shearwater Calonectris diomedea, Great Shearwater Puffinus gravis, Sooty Shearwater Puffinus griseus, Manx Shearwater Puffinus puffinus, Mediterranean Shearwater Puffinus yelkouan (mauretanicus), and Little Shearwater Puffinus assimilis. The two large shearwater species are largely present from late July to early October in the deeper waters (>1000m) of the Bay (44-47°N). The largest concentrations of birds are present at presumed areas of upwelling near the northern Celtic-Biscay shelf edge, where flocks of up to 1000 Great and 400 Cory s Shearwater have been recorded from surveys. Unlike Cory s Shearwater, Great Shearwater is often still found in large numbers up to late October. Sooty Shearwater does not occur in large numbers but is distributed throughout the survey area on migration. Manx Shearwater is found in the largest numbers in the English Channel and off the Brittany coast in the April-June period and is largely absent from the Bay itself. Mediterranean Shearwater occurs in low numbers with a fairly even distribution of records from May to November. Little Shearwater is a rare although regular species August-October.