Theses and Dissertations


Title: Effect of pituitary injections and other factors on reproduction of pond fishes

Name: Chaudhuri, Hiralal

Degree: MS

Chair: Dr. Homer S. Swingle

Resides: FAA Library

University: Auburn

Location: Auburn, Alabama

Date: 1955

Pages: 78

Keywords: Goldfish,Fathead minnow,Bigmouth buffalo,Smallmouth buffalo,Common carp,Carassium auratus,Pimephales promelas,Megastomatobus cyprinella,Ictiobus bubalus,Cyprinus carpio,Pituitary injections,Reproduction.

Abstract:

Experiments on factors affecting spawning of pond fishes were conducted in troughs with flowing water and in aquaria in the laboratory with goldfish (Carassius auratus [Linnaeus]) and fathead minnow (Pimephales promelas promelas Rafinesque) and in ponds in the field with goldfish, bigmouth buffalo (Megastomatobus cyprinella [Valenciennes]), smallmouth buffalo (Ictiobus bubalus [Rafinesque]), and the common carp (Cyprinus carpio Linnaeus). The effects of fish pituitary gland injections from different sources, in different doses, and with repeated doses were studied under varying conditions of temperature, light, and fresh water in the laboratory. The field experiments were mainly restricted to the study of the effect on reproduction by keeping fishes in crowded conditions and subsequently releasing them into fresh water at various temperatures: pituitary injections were also tried.The results of pituitary gland injections indicate that goldfish could be induced to spawn earlier than the normal spawning season and that injection of goldfish pituitary worked better than that with pituitaries from other fishes. Mammalian sex hormone did not affect goldfish. The minimum dose injected was 0.1 mg. of acetone-dried fish pituitary gland, and this induced spawning by goldfish. Repeated doses of small quantities of fish pituitary glands gave better results than a single high dose. The time of response in injected goldfish depended on the stage of maturity of the gonads.Injected goldfish spawned at a water temperature of 56o F. but did not respond at 52o F. At a temperature of 65o F, goldfish spawned the most readily. Light had no measurable effect on the spawning of goldfish. Fresh water accelerated and intensified spawning, although fishes did spawn after injection without change of water. The injection of carp pituitary gland in fathead minnows hastened the appearance of secondary sexual character in the males. The field experiments with bigmouth buffalo, smallmouth buffalo, and carp showed definitely that release in fresh water at proper temperatures precipitated spawning if the gonads were mature. Bigmouth buffalo successfully spawned even in a small circular concrete pond of 12 feet in diameter. Smallmouth buffalo did not respond as successfully as the other fishes when released into fresh water.

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