Applications of Endocrinology to Fish Culture

Abstract

Endocrinology has, or may have, important applications in four major activities of fish culture viz induced breeding, larval rearing, "grow-out," and broodstock development and management. The current state of knowledge regarding these applications is reviewed and discussed. For induced breeding, this includes discussion of the use of fish pituitary extract ± HCG (human chorionic gonadotropin); HCG alone; partially purified teleost gonadotropins; LH–RH (luteinizing hormone–releasing hormone) and its superactive analogues; clomiphene citrate and other antiestrogens; corticosteroids ± pituitary extract; progestogens ± pituitary extract; and prostaglandins. In larval rearing, use of thyroxine (Eltroxin), which accelerates larval and fry development and growth in a few teleosts, is suggested. In "grow-out" (growth of fry to marketable size), the use of hormones to enhance fish growth and the use of steroids in sex control to facilitate monosex culture are briefly reviewed. Finally, in broodstock development and management, the use of hormones to induce spermatogenesis or vitellogenesis in broodfish is considered.Key words: endocrinology, hormones, fish culture, induced breeding, larval rearing, fish growth enhancement, sex control, induced gonadal development