Sex Determination of Live Striped Bass, Roccus saxatilis (Walbaum), by Biopsy Technique

Abstract

There is no practical and exact way of telling the sex of the striped bass, Roccus saxatills (Walbaum), from external characteristics since this species does not exhibit sexual dimorphism, except when they are running ripe. A method of gonadal biopsy is described here whereby a tissue specimen of the gonad is obtained from a live fish for sex determination. A pair of serrated alligator-jawed forceps is used as the tool for obtaining the gonadal tissue via the sterile urogenital tract.The method was tested on two age groups of fish, ages II and III, in conjunction with the use of a nylon-streamer tag. The results of a duplicated test series show that in the laboratory correct tissue sampling was attained in 19 of 20 tries (95%) and sex identification was I005~ correct in age III and 89~ correct in age II. Only 3 of 20 biopsied fish were found to have unhealing gonad excision sites at autopsy. A mixed hierarchial model analysis of variance indicated near significant differences in survival time at the 59~ level among the three subgroups of fish, i.e., biopsied and tagged, tagged only, and control.

Bass populations and movements on the west coast of the U.K.

“…In view of the possibility that the two sexes of Dicentrarchus labrax may also differ in their migratory habits it is desirable that in future tagging projects efforts be made to sex the tagged fish. A method of gonadal biopsy has been tried successfully on the striped bass by Ritchie (1965), adapting an earlier necropsy technique of Sykes (1958). In this method a serrated alligator-jawed ear-forceps was inserted in the uro-genital duct to obtain samples of gonadal tissue for later laboratory examination and sexing.…”

Sex identification in immature Eurasian perch ( Perca fluviatilis ) using ultrasonography

“…Current techniques for sexing or characterizing maturation in fish include biopsy of the gonads (Ritchie, 1965), plasma analysis of steroids, sex hormones and proteins levels (Le Bail & Breton, 1981), genetic techniques (Griffiths et al, 2000), external urogenital characterization (Vecsei et al, 2003), palpation (Kano, 2005), endoscopy (Hurvitz et al, 2007), coelioscopy (Melillo Filho et al, 2016) or urogenital catheterization (Zarski et al, 2019). Except for external urogenital characterization and palpation techniques, these non-lethal but invasive methods are generally timeconsuming, expensive and sometimes dependent on the maturity of the fish.…”