Quantifying Male Reproductive Performance of Blue Catfish (Ictalurus furcatus) to Improve Hatchery Production of Hybrid Catfish

Abstract

Catfish farming constitutes about 60% of total U.S. aquaculture production, where the channel catfish, Ictalurus punctatus female × blue catfish, I. furcatus male hybrid accounts for >50% of the harvest. Current hatchery technology to produce hybrids requires the sacrifice of males for in vitro fertilization, and sperm are often of low quality/quantity, negatively affecting fertility and hatch rates. Thus, the overall objective of this thesis was to understand blue catfish male reproduction as it relates to hybrid production. Specific objectives were to: (i) compare sperm swimming kinematics and health metrics before and after cryopreservation; (ii) determine minimum quantity of frozen-thawed sperm required to maximize hatching success; (iii) decipher how early offspring development is affected when eggs were sired with fresh or frozen-thawed sperm; and iv) determine if there is a relationship between reproductive performance traits and sperm kinematic traits utilizing both fresh or cryopreserved sperm. Sperm kinematic traits and health metrics decreased after cryopreservation, adding greater than 5.0×104 sperm cryo or fresh?per egg had no significant effect on hatching success, and there was no decline in offspring performance when sired with cryopreserved sperm. Additionally, reproductive performance traits correlated with fresh and cryopreserved sperm kinematic traits. In conclusion, blue catfish male reproductive performance for more practical hybrid production was further quantified.