Andrzej Kapusta, Maja Prusińska, Tomasz K. Czarkowski
ABSTRACT. Natural recruitment is one of the factors determining the status and structure of fish resources, and it also has an impact on the execution of fisheries management. Vendace is an important element of fisheries management in Lake Wulpińskie, which is why determining the level of other species foraging on its eggs is very important. To this end, the food composition of fish caught in vendace spawning grounds was examined. Most of the fish caught (55%) had empty digestive tracts, including that of the only common bream and nearly all of the silver bream (88.9%). The main dietary component of perch was fish, while in roach it was zebra mussel. Vendace eggs were an insignificant component of the diets of both perch and roach. Vendace eggs (151 eggs) were only confirmed in the stomach of one perch specimen and in the digestive tracts of two roach specimens in quantities of 90 and 121 eggs. In general, the level of foraging of co-inhabiting fishes on vendace eggs was low. Taking into consideration the trophic status of the lake, one can conclude that physico-chemical factors have a greater impact on the effectiveness of natural vendace spawning than does foraging.
Keywords: Coregonus albula, eggs, foraging, Perca fluviatilis, Rutilus rutilus
Przyjęto po recenzji 8.02.2019 r.