Relationships between Fishery Activities and Presence of the Audouin's Gull (Larus audouinii) in the Columbretes Islands

Abstract

-This study presents quantitative evidence for a link between the timing of fishery activities and movement patterns of Audouin's Gull, Larus audouinii, in the Mediterranean Sea. The study was conducted in 1992 and 1993 in the Columbretes archipelago, Natural Reserve (Castell6n, Spain). The diurnal pattern of Audouin's Gulls presence on the island differed significantly between fishing and non-fishing days. Most gulls abandoned the island to visit the trawlers during the hours in which they were hauling back nets near the colony. In contrast, the majority of gulls remained in the roosting area during the non-fishing days. This study shows that Audouin's Gulls derive food from commercial fishing activities, but the extent to which this threatened species depends on the fishery remains unknown. Received 7 December 1994, accepted 10 February 1995.