Otter diet in relation to fish availability in a fish pond in Hungary

Abstract

Otter diet in relation to fish availability in a fish pond in Hungary. Acta Theriologica 41: 127-136.The food composition of otters Lutra lutra (Linnaeus, 1758) was investigated in an artificially established fish pond of 12 ha in south-western Hungary between December 1991 and November 1994. In the fish pond fish farming was carried out with the introduction of different species during the first two years of the investigations, while the filling up of the pond with water and its planting did not come about in the third year. The diet of otters was examined by spraint analysis (873 samples). The most important prey of otters was fish amounting 40 to 100%; the variation was due to season, method of farming and density and composition of the fish stock available. There was a close relationship between the frequency of occurrence of different fish species in the otter diet and the amount of fish available to the otters. The correlation coefficients (rp) were 0.56 (p < 0.05), 0.87 (p < 0.0001) and 0.93 (p < 0.0001) in the three years. Fish species that are predominant in the fish pond were the most frequent in the otter diet. Most of the fish eaten were below 50 g, ie 55, 88 and 90% respectively in the three years. Prey fish weighing more than 1000 g were found in scats only in the second year, and in a low proportion (1%). Economically important fish species constituted 33, 9 and 3% of the otter diet in the three years. The economic consequences of otter predation on fish are discussed.

Diet of the Eurasian otter Lutra lutra on small watercourses in Western Poland

“…Our study confirms the generalist feeding pattern of the otter, which used fish species according to their local and seasonal availability (Lanszki and Körmendi 1996, Jędrze-jewska et al 2001, Lanszki et al 2001, Poledník et al 2004.…”

“…Obviously, to enable these ecological adaptations the otter is flexible in its feeding habits (Brzeziński et al 1993, Carss 1995, Lanszki and Körmendi 1996, Jędrzejewska et al 2001, Clavero et al 2003. Although there is no doubt that the otter is a piscivorous (Chanin 1981, Lanszki and Molnár 2003, Brzeziński et al 2006, it is characterized by flexibility in the type of prey caught (Lanszki et al 1999).…”

Eurasian otter (Lutra lutra) prey selection in response to a variation of fish abundance

“…Accordingly, the otter may be considered a generalist aquatic predator, even though only a few studies have simultaneously compared otter diet to food availability (Lanszki & Körmendi 1996;Carss et al 1998;Lanszki et al 2001;Ruiz-Olmo et al 2001).…”

Seasonal and spatial differences in feeding habits of the Neotropical otter Lontra longicaudis (Carnivora: Mustelidae) in a coastal catchment of southeastern Brazil

“…The predation on anurans of the genus Bufo has been documented for Lutra lutra (SLATER 2002). The time of re- production of B. crucifer and other frog species coincides with their high frequencies in otter spraints, probably because this is the period when the anurans are more exposed for sexual activities, making them easier prey for otters (LANSZKI & KORMENDI 1996, ROCHE 1998, JEDRZEJEWSKA et al 2001, SLATER 2002). Although we cannot be sure what anuran species were consumed by the otters during this study, the fact that anuran consumption increased in the dry season, during which most anuran species have decreased densities, may indicate Bufo crucifer as a probable anuran species consumed by the otters in the study area.…”

“…Even when considering the frequency of total occurrence of this group in the samples analyzed in the present study (FO = 9.56%), frogs occurred more than previously observed for the species. For other otter species, such as Lutra lutra, frogs occurred in higher frequencies, reaching 40% of the frequency of occurrence in the spraints (JENKINS & HARPER 1980, LANSZKI & KORMENDI 1996, ROCHE 1998, JEDRZEJEWSKA et al 2001. The seasonality verified in the predation of frogs observed in the present study has already been documented for other otter species.…”