Chemical signatures of multi-species foraging aggregations are attractive to fish

Abstract

ABSTRACT: Fish navigate a sea of chemical signatures, which can guide their movements through their environment. Chemoreception is integral to how larval fish find reef habitat and adult fish find home. Yet, the chemicals responsible for driving fish behavior are largely unknown, and the chemical seascapes through which fish navigate are changing with shifting environmental conditions. To investigate the possible suite of chemical cues employed by fishes in their search for foraging hot-spots, we collected 10 l samples of water from the center of natural foraging aggregations. These aggregations were composed of multiple fish species from several trophic levels over the reefs of Belize. We then conducted bioassays on wild-caught Abudefduf saxatilis (N = 84) in laboratory flow tanks using previously frozen seawater samples and extracted compounds from foraging aggregations and paired control sites. Capturing seawater from the midst of natural foraging aggregations, filtering this over C18 resin, and presenting the eluted compounds to a reef fish elicited a significant behavioral response of spending more time in water that contained C18 extracts from fish aggregations compared to controls (p = 0.03). These results indicate that chemical cues collected within the middle of multi-species fish foraging aggregations are attractive to adult reef fish and suggest that chemical signatures associated with foraging aggregations might be important olfactory guides for fish.