Ontogeny of thermal preference in four species of viviparous fishes (Embiotocidae)

Abstract

The preferred temperatures of juveniles of four embiotocid species were determined in a laboratory gradient apparatus. Juvenile Embiotoca jacksoni and Micrometrus minimus preferred warmer water than adults, although adults and juveniles of both species coincided in field occurrence. Hypsurus caryi adults and juveniles preferred equivalent temperatures. Neonate Cymatogaster aggregata preferred colder water than adults. Therefore, thermal preference was not a species characteristic but varied ontogenetically. There was agreement between temperatures occupied under gradient conditions and acute laboratory preferred temperatures for juveniles of all species except C. aggregata, which preferred cooler temperatures than actually occupied.