A new method to determine sex and gonad size in live fishes by using ultrasonography

Abstract

A method to determine, non-invasively, sex and gonad size employing ultrasonography and using Atlantic salmon, Salmo salar Linnaeus, as an example, is described. Although gonads of immature males may be difficult to discern, gonads of females are always visible and hence sexing is possible by deduction. Gonad diameter can be estimated by ultrasonography; the correlation coefficients between ultrasonographic and ruler-derived measurements were 0.926 for females and 0.754 for males. The appearance of ultrasonographic images of the gonads during sexual maturation are described. The results are discussed and suggestions made to improve the quality of images and reliability of measurements.

Determination of sex and maturity in Acipenser stellatus by using ultrasonography

“…Immature salmon females were detected by the small size of the ovary (Reimers et al, 1987;Mattson, 1991), but for cod it was not possible to differentiate immature females (Karlsen and Holm, 1994). Immature salmon females were detected by the small size of the ovary (Reimers et al, 1987;Mattson, 1991), but for cod it was not possible to differentiate immature females (Karlsen and Holm, 1994).…”

Age composition, growth, and reproductive biology of yellow catfish (Peltobagrus fulvidraco, Bagridae) in Ce Lake of Hubei Province, Central China

“…Sex differentiation is one of the most important indexes in fish biology study and also the preliminary step for artificial breeding. Both morphological differentiation and ultrasonography methods can be used to determine fish sex (Mattson 1991). Three types of sexual characteristics differentiation could be summarized in fishes: (1) body size of females > that of males; (2) body size of females < that of males; (3) similar size of both sexes with partial differences on morphology .…”

Energetic consequences of reproduction in Atlantic cod (Gadus morhua) in relation to spawning level of somatic energy reserves

“…Cod were then anaesthetized in a solution of metomidate hydrochloride (5 mg·L -1 ), measured (±0.1 cm), weighed (±1 g), scanned with ultrasonography to identify sex (Mattson 1991), and individually identified with a visual implant tag (Northwest Marine Technology, Shaw Island, Wash.) inserted in the first dorsal fin. Fish were paired (one male and one female) into smaller 1.2-m 3 circular tanks to individually monitor egg production of females through their spawning cycle.…”