Predation by marine‐feeding otters (Lutra lutra) in south‐west Portugal in relation to fluctuating food resources

摘要: Patterns of predation by otters (Lutra lutra) inhabiting the Portuguese south-west rocky coast, were inferred from analysis 757 spraints collected along a 5-km stretch shore, November 1990 to October 1993. Undigested remains identified, counted and measured; length weight ingested prey was estimated regression equations. Monthly fluctuations in diet compared changes abundance primary species coast. The most commonly taken fish had median lengths between 6.7cm 15.0cm, weights 3.5 g 34.2g. Corkwing wrasse dominated terms biomass (51.6%), important numbers (22.6%). Gobies (19.4%), Valenciennes' blennies (15.0%), shannies (1 1.4%), crayfish (7.2%), shore rocklings (4.1%) other numerically prey. contribution gobies (14.5%), (6.7%) conger eels (5.5%) also significant. dominant sizes consistent over years. From late winter early spring corkwing gobies, whereas for rest year shannies, important. these last small at all times year, always Prey twice as heavy spring. There close correspondence seasonal variation but dietary could be accounted simply wrasse. In Portugal, food resource seems wrasse, probably because they are large easy catch. exploited local fishermen, possibility competition humans should investigated.