SPAWNING INDUCED PREMATURELY IN TROUT WITH THE AID OF PITUITARY GLANDS OF THE CARP1

Abstract

THIS PAPER deals with the problem of inducing rainbow trout to spawn prematurely under the influence of hormones contained in the pituitary gland of the carp and suggests endocrinological methods practical to fish culture. Certain investigations of this type have been made by other workers. Houssay (I) injected hypophyses of Micropogon and Luciopimelodus into the ovoviviparous fish Cnesterodon with the result that expulsion of eggs occurred I5 days before the voluntary spawning time. In northeastern Brazil certain fishes spawn only after the heavy rains that follow a long period of drought. To procure eggs from these fish for artificial hatching purposes Cardoso (2) induced spawning prematurely in Prochilodus by injecting fish hypophyses. Von Ihering (3, 4) using this method, induced spawning prior to the jrainy season (the normal spawning time) in Prochilodus,Astyanax and Hoplias. He secured expulsion of eggs within 24 to 96 hours following a single intramuscular injection of 1 to 5 hypophyses of these same species.