Environmental determination of sex in Apistogramma (Cichlidae) and two other freshwater fishes (Teleostei)

Abstract

Environmental sex determination by temperature could be revealed significantly in 33 Apistogramma-species and in Poecilia melanogaster. In some, but not all, Apistogramma-species pH also influences the sex ratio, whereas neither temperature nor pH affect the sex ratio of Pseudocrenilabrus multicolor victoriae. The sex in offspring of A. trifasciata is determined within a sensitive period of about 30 to at least 40 days after spawning. © 1996 The Fisheries Society of the British Isles.