Aquaculture & Fisheries

Biography

Biography: Kazuko Miyagawa Kohshima

Abstract

It is known that each anemone fish inhabits species-specific symbiotic anemone(s) in the Indo-Pacific Ocean, and has been demonstrated that each anemonefish juveniles reach their hosts by recognizing chemicals emitted from symbiotic anemone(s). We studied this species-specific host-recognition system of anemonefish experimentally, with a particular focus on the function of imprinting using naive Amphiprion ocellaris juveniles. We demonstrated the embryonic and immediate post-hatching learning of chemical cues via the parents' host in A. ocellaris through a host-exchange experiment with egg batches during hatching. This is why anemonefish parents lay their eggs very close to their host anemone, the eggs almost always touching the host's body or tentacles. The memory obtained from such imprinting operates at the time when juveniles first search for their hosts. Unexpectedly, innate recognition was found to exist not only in the symbiotic host species but also weakly in two non-partner species. Innate recognition alone is not sufficient. Imprinting via the parents' host complements innate recognition, leading to rigid species-specific host recognition. Imprinting by the parents' single host provides a sufficient cue for reaching the two host species. Furthermore, when combined with imprinting, innate recognition of non-partners serves to supplement the recognition of those species, leading to substitute partnerships that are only observed in some localities. In short, innate non-partnerrecognition is considered to be a type of spare recognition. We will discuss potential functions of imprinting in the host-recognition system.