Chemosensory Systems in Fish: Structural, Functional and Ecological Aspects

Abstract

In fish, the chemical senses are represented at least by three separate modalities: the sense of olfaction, the system of solitary chemosensory cells, and the taste system. All three modalities are phylogenetically old and well conserved to this date. The chemical senses enable the fish to orientate, to follow and find food or prey. They help to avoid enemies or predators, but also to interact with conspecifics and to find sexual partners. Chemical senses are common to all systematic groups of fish and are also present in cyclostomes (hagfish and lampreys). As a rule, the chemical senses are of great importance to aquatic vertebrates, and are especially well developed in some night-active species and those living in the dark (e.g. in caves) or in muddy waters. All three chemical senses develop early during ontogeny, and often are functional at time of spawning.