OTTER (LUTRA LUTRA L.) DAMAGE IN COMMERCIAL CARP PONDS OF SOUTHERN POLAND

ABSTRACT- The diet of the otter Lutra lutra was studied at 198 commercial carp Cyprinus carpio ponds (total area 811.9 ha) located near Zator, an Experimental Fish Farm in southern Poland. The food habits of the otter were determined by the analysis of 344 spraints collected monthly from December 2000 to December 2001. Data were expressed as frequency of occurrence and per cent of biomass. Fish represented the main food resource of otters, occurring in 97.4 % of faecal samples. Carp occurred in 9.3 % of faecal samples. Percentage share of carp in biomass of food consumed by otters averaged 14.2 % per year. The 97.6 % of eaten carp was classified as carp fry production, ranging between 3.0 cm and 7.9 cm in body length (mean: 5.7 ± 0.92 SD). The economic consequences of otter predation on fish are discussed