Selective predation by carp (Cyprinus carpio L.) on benthic molluscs in Skadar Lake, Yugoslavia

Abstract

Analysis of predation by carp (Cyprinus carpio L.) on mollusc species in Skadar Lake, Yugoslavia, indicated both generalized and specific features of a predator‐prey interaction. Vertical distribution of molluscs in sediments seemed unrelated to predation rates by carp. Although size selective predation may occur, electivity indices appeared most related to shell shape and thickness. Of the three most abundant species, electivity was high for Valvata piscinalis but low for Pyrgula annulata and Dreissencia polymorpha. Valvata has a more readily crushed shell, a higher proportion of occupied shells and a greater percentage of organic content than Pyrgula. Although a potentially preferred prey item, Dreissencia probably escaped intensive predation by being attached to larger objects. Carp appeared to utilize a sequence of tactile and gustatory cues in the prey selection process.