Physiology of Finfish and Shellfish (2+1)

3.1.25. Separate Sexes

The sexes are separate in most crustacea and usually can be differentiated from each other by secondary sex characters. Chief among these characters are the size and shape of the body, appendages, or both, and placement of the genital apertures. For these crustaceans, reproduction functions similarly to many of the fish species. The female produces eggs in the ovaries that are either released in the water or attached to the female waiting for fertilization. The male then fertilizes the eggs. Lobsters perform serial monogamy, meaning the males are engaged with only one female at a time, but will repeat the fertilization with many females. The female sheds her outer shell and moves into the male's lair for approximately two weeks.