Coral Fish in Symbiotic Associations: Benefits and Risks

Abstract

Studies on the feeding, behavior, and infection rate of fish in symbiotic groups associated with corals Pocillopora sp. and Acropora sp. (Nha Trang Bay, Vietnam) have demonstrated the serious risks of the tactics called “refuge-based aggregation” (refuging in groups). Feeding conditions and the efficiency of defensive behavior worsen with increasing numbers of fish in groups and with fish size. When aggravated with an increased parasite load, these factors force the largest fish to leave the symbiotic association. Leaving the colony of the host, fish have access to more diverse food resources and decrease the parasite load, interacting with cleaner fishes. The combination of some negative factors restricts the number of fish in groups of refugebased aggregators and their distribution among coral fishes. The main groups of coral reef fish, parabionts, and inbionts use different tactics of feeding and defense against predators and parasites.