Nagaraj G. Chatakondi

Channel catfish (Ictalurus punctatus) x blue catfish (I. furcatus) hybrid fry production is variable and inconsistent in hatcheries, and there is sometimes an unsatisfactory reduction in the yield of viable fry that occurs during the final weeks of a spawning season. There are several possible reasons for these inconsistencies of production—this study investigates two: hatchery water temperature and the species of the parental male. Regarding water temperature, broodfish are often exposed to 30°-35° C temperature in ponds during the final weeks of spawning season in late spring, resulting...

Stress is unavoidable in aquaculture and hence strains of fish that are resilient and adaptable to stress need to be developed. In teleosts, cortisol is considered the primary stress hormone and often increases in cortisol concentration correspond to a stress response. The objective of this study was to assess if cortisol responsiveness to stress in channel catfish (Ictalurus punctatus) influences susceptibility to Enteric Septicemia of Catfish (ESC) caused by Edwardsiella ictaluri under controlled conditions. Juvenile channel catfish were subjected to standardized hypoxia stress (1.8 mg L...

Most hybrid catfish are produced by fertilizing eggs from hormone-induced, strippable channel catfish (Ictalurus punctatus) females with sperm from blue catfish (I. furcatus). Water to most hatcheries is supplied from 300 to 400-m deep aquifer, yielding geothermal water of 25-30 C with low level of calcium hardness and hence supplemented with an external source of calcium. Many catfish hatchery water sources have low calcium concentrations and are supplemented with an external source of calcium. Nevertheless, failure of calcium pump or delivery system in commercial catfish hatcheries...