Effects of Positional Overlap on Interactions and Co-occurrence of Follower Fishes in Benthic Foraging Associations

Abstract

Opportunistic predatory reef fishes commonly follow foraging benthivores to feed on prey disturbed by the benthivores. This study examined factors that may restrict the number and the species composition of follower fishes. Association groups common on the reefs around Bonaire were followed and videotaped. The follower compositions and interactions were quantified. Time spent by the followers in different positions around the nuclear benthivore was calculated. Follower species occupied some positions more often than others, and the preferred positions were species- specific. A high degree of overlap in these positions corresponded to repelling interactions between followers and to the absence of their co-occurrence in the associations. A low degree of the positional overlap corresponded to the absence of repelling interactions and to co-occurrence of the followers in the same association.