Effects of broodfish sex ratio, broodfish stocking density, and postspawn broodfish holding‐pond density on reproductive efficiency in pond‐spawned Channel Catfish

Abstract

AbstractObjectiveThree trials were conducted to determine the effects of broodfish management on reproductive efficiency of pond‐spawned Channel Catfish Ictalurus punctatus.MethodsTrial 1 compared male to female broodfish sex ratios of 1:1 versus 1:4, trial 2 compared low (1065 kg/ha) versus high (2050 kg/ha) broodfish stocking densities, and trial 3 compared low (1525 kg/ha) and high (5780 kg/ha) postspawn broodfish holding‐pond densities on measures of reproductive efficiency.ResultMales had lower survival than females in all trials. Age, weight, and survival of broodfish were similar for each treatment within trials. A higher percentage of females spawned at the 1:1 male to female ratio than at the 1:4 ratio (40.8% versus 12.5%), resulting in more eggs per hectare, eggs per kilogram of broodfish, fry per hectare, and fry per kilogram of broodfish for the 1:1 ratio compared to the 1:4 ratio. Male spawning success (~31%) was similar for 1:1 and 1:4 sex ratios. Spawning fish weighed more than nonspawning fish for both sexes, and surviving males weighed less than nonsurviving males in trial 1. In trial 2, the percentage of egg masses collected per female stocked was higher for the high broodfish density than the low density (34.0% versus 16.4%), resulting in more eggs per hectare and fry per hectare for the high stocking density resulting in whole‐farm economic benefits ranging from US$323/ha to $828/ha primarily from the reduction in the area required for broodstock.ConclusionResults indicate that the 1:1 male to female broodfish ratio (trial 1) and high broodfish stocking density (trial 2) resulted in better reproduction than the 1:4 sex ratio and low broodfish stocking density. The effects of low versus high broodfish holding‐pond densities did not affect reproductive output.