Hybrid Catfish Aquaculture: Dads Really Do Matter

Authors: MYERS, JAELEN - Auburn University; DUNHAM, REX - Auburn University; BUTTS, IAN - Auburn University; Chatakondi, Nagaraj

Submitted to: Popular Publication
Publication Type: Popular Publication
Publication Acceptance Date: 11/24/2019
Publication Date: 12/2/2019
Citation: Myers, J., Dunham, R., Butts, I., Chatakondi, N.G. 2019. Hybrid Catfish Aquaculture: Dads Really Do Matter. Popular Publication. 2:7-8.

Interpretive Summary: Hybridization of channel catfish with blue catfish had improved the production efficiency of catfish production and is widely adopted in the US farm-raised catfish industry. Hybrid catfish fry production has been increasing over the years but is inconsistent and variable in hatcheries. Effects of incubation temperature (environment) and parental (maternal and paternal) species and their interactions during embryonic development to know their variations in survival and development of hybrid catfish fry. A full-factorial mating design with 4 channel catfish females with 5 blue catfish males to produce 20 unique hybrid catfish families were incubated in 80 °F and 90 °F incubation temperatures. Variations in performance traits of hybrid catfish embryo were portioned to paternal, maternal, and their interactions within two incubation temperatures. Embryonic survival ranged from 45-93% by 120 degree-hours post fertilization (critical period) and maternal effects were responsible for 51% of the variation. Incubation temperature significantly impacted hatching success of hybrid catfish eggs. Deformities and larval morphology were also monitored during the critical period. This study documented developmental stages of hybrid catfish embryo at important stages of development. Optimal egg quality, incubation temperature and paternal contributions were important factors during the hybrid catfish development. Selecting superior broodfish will likely result in consistent and increased hatchery production of hybrid catfish fry in commercial hatcheries.

Technical Abstract: In this study, blue catfish males and channel catfish females were paired to create 20 unique hybrid families. Offspring from each family were then split into 2 temperature-controlled environments and followed over time (see Figure 1), based on conditions that mimic early (26.6 oC) and late (32.2 oC) seasonal temperatures. Embryonic survival, hatch success, as well as fry morphology and deformities were quantified at hatch, during the mid-yolk sac transition, and swim-up stages of development. Variation in early performance traits were then partitioned to mom and dad as well as family x environmental interactions. Final embryonic survival showed substantial variability between families from 45-93% and was not impacted by incubation temperature. Instead and not surprisingly, maternal effects were responsible for large amounts of the variation (50%) but dad’s contribution also became apparent during later stages (7%). High temperatures on the verge of suboptimal proved to be the enemy for hatch with a significant reduction at 32.2 oC (from 40% to 32%). Therefore, we concluded that temperatures at the start of the spawning season yield higher hatch success, which is certainly preferable in any hatchery, Also, mom and her egg/yolk quality were very apparent on hatch (65% of variation), and dad continues to play a determining role (12%) for hatch. Like we saw in the embryos, it varied drastically between families (14-71%). For larval morphology, fry reared at 32.2 oC had smaller body sizes at each developmental stage due to faster growth rates and earlier time to hatch. Matching the embryonic and hatch results, morphology indices were also influenced by the parents with mom’s influence highest on yolk-related traits (up to 80%) and dad peeking through (up to 29%). Family × environmental interactions were also observed across our data spread because the extent of fish variability differed within each rearing temperature.