Diel pattern in common carp landings from angling competitions corresponds to their assumed foraging activity

Abstract

Increased foraging activity increases vulnerability of fish to angling. Foraging activity of free-ranging common-carp (Cyprinus carpio L.) is assumed to be mostly nocturnal. Thus, it is assumed that the number of carp caught in angling competitions will be higher during the night than during the day. Also, common carp are able to learn the position of new feeding spots that they exploit repeatedly. This ability may lead to an increase in number of landed carp each consecutive day of angling competitions as new carp learn the position of newly established feeding-spots. These hypotheses were tested using data from 14 carp-oriented angling competitions conducted in four European countries. As expected, carp landings were most frequent at night and the number of carp landed increased non-monotonously throughout the competitions. These findings may be important for essential feeding biology of wild common carp with valuable implications for anglers and management of non-native carp.