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Submitted to: Southeastern Association of Fish and Wildlife Agencies Conference
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 12/6/2019 Publication Date: N/A Citation: N/A Interpretive Summary: Channel x blue hybrid catfish fry are reliably produced in hatcheries; however, hatchery fry production is variable and reduced during the spawning season. Parental and early embryonic rearing environments are essential components for continued and increased production of hybrid catfish fry production in hatcheries. Temperature is a critical element during embryogenesis in fish and differences in paternally derived variations are expected during this critical period. Our findings suggest blue catfish male sired eggs had 5.6% higher hatching success, while hatching success was 8% higher when incubated at 26.6 °C than 33.2 °C hatching waters. Paternal and incubation temperatures had minimal impact on subsequent progeny performance. Practical solution to overcome exposure of fully mature gravid female channel catfish to pond waters of higher than optimal water temperatures during the spawning season is unavoidable. Hence, holding broodfish in deeper ponds or flushing broodfish ponds with well water with occasional paddle wheel aeration to cooler pond surface is practical. Genetic manipulation and environment manipulation are other means to address this practical problem in hybrid catfish hatcheries. Technical Abstract: Channel catfish, Ictalurus punctatus X Blue catfish, I. furcatus hybrid fry production in hatcheries is inconsistent during the season and often reduced during the final weeks of the spawning season. Spawning of broodfish, embryo development, survival of embryos occurs within a narrow range of water temperature. Incubation temperature has a direct effect on the timing of embryonic development and hatching success. A study was conducted to assess the effects of two incubation temperatures at 26.6 °C and 32.2 °C on stripped eggs produced during the peak season and sired by two parental males. Eight gravid channel catfish were induced to ovulate with 20+80 µg luteinizing hormone releasing hormone/kg body weight (BW) and stripped eggs from each female were fertilized either with channel catfish sperm to produce half-sib channel catfish or blue catfish sperm to produce hybrid catfish group families incubated at two temperatures until hatch. Hatching success, survival and growth of ensuing fish were determined. Mean hatching success of hybrid catfish eggs (49.6%) was higher (P<0.05) than channel catfish eggs (44.0%) incubated at 26.6 °C; similarly, mean hatching success of hybrid catfish eggs (43.7%) was higher (P<0.05) than channel catfish eggs (35.7%) at 32.2 °C incubating waters. The length of the hatch for eggs incubated at 26.6 °C (120-h) was longer (P<0.05) than 32.2 °C (99-h). However, parental male or incubation temperature did not influence progeny performance. Eggs hatched from females during peak spawning temperatures had higher hatch at 26.6 °C compared to 32.2 °C. Parental and early embryonic rearing environments are essential components for continued and increased production in catfish hatcheries. |
