Technique for sexing spotted barramundi, Scleropages leichardti, and northern spotted barramundi, S. jardini (Osteoglossidae)

摘要

The spotted barramundi, Scleropages leichardti, and the northern spotted barramundi, S. jardini, are primary freshwater fishes endemic to northern Australia. Besides their evolutionary and conservation importance, Scleropages are highly valued aquarium fish and sports-fish. Spotted barramundi are cultured commercially on several hatcheries in Queensland, but the lack of sexual dimorphism makes the identification of sex and management of broodfish difficult. Hamar and Mary Midgley and Stuart Rowlanddescribe a technique, based on the use of probes and the appearance of the vent region to sex both species. Females have two distinct openings posterior to the anus, a genital pore and a urinary pore, whereas males have only a single urogenital pore. Theuse of this technique enables the sex of spotted barramundi and northern spotted barramundi to be quickly and reliably determined, with minimal stress and handling of individual fish.