Biology of Finfish and Shellfish (2+1)

4.3.5. Five scale Maturity stage Description

Females

I. Immature

Ovary small, firm, no eggs visible to the naked eye

II. Maturing virgin or resting

Ovary more extended, firm, small oocytes visible, giving ovary a grainy appearance

III. Developing

Ovary large, starting to swell the body cavity, colour varies according to species, contains oocytes of two sizes

IV. Gravid

Large, filling or swelling the body cavity, when opened large ova spill out

V. Spent

Ovary shrunken, flaccid, contains a few residual eggs and many small ova

Males

I. Immature

Testis small, translucent, whitish, long, thin strips lying close to the vertebral column

II. Developing or resting

Testis white, flat, convoluted, easily visible to the naked eye, about ¼ length of the body cavity

III. Developed

Testis large, white and convoluted, no milt produced when pressed or cut

IV. Ripe

Testis large, opalescent white, drops of milt produced when pressed or cut

V. Spent

Testis shrunk, flabby, dirty white in colour