2012 Annual Report
1a.Objectives (from AD-416):
Determine effects of male:female ratio, stocking density, and post-spawning consolidation on spawning success in channel catfish.
1b.Approach (from AD-416):
This research will take place in 3 phases over 36 months, with each 12 month period being devoted to each of the 3 spawning trials. The first trial will determine the effects of male to female ratios of 1:1 and 1:4 on spawning success in channel catfish. Broodfish from a strain being developed as part of the USDA-ARS’s breeding program will be used in the study. Broodfish will be randomly assigned to treatments and stocked into 0.1 ha spawning ponds, with 6 replicate ponds per treatment. Ponds in both treatments will be stocked at approximately 1,100 kg/ha and the number of males and females in each pond will be adjusted to the proper sex ratio. The second trial will compare stocking rates of 1,100 and 2,200 kg/ha on reproductive success of channel catfish. At stocking brood fish will be randomly assigned to each treatment and stocked into 0.1 ha spawning ponds, with 6 replicate ponds per treatment at a sex ratio of 1:1 for both treatments. The third trial will determine effects of consolidating broodfish at end of the spawning season on spawning the following year. Fish from a large, unrelated spawning trial stocked at approximately 1,100 kg/ha will be used in this study. Fish from that trial will be harvested at the end of spawning (end of June) and a portion will be restocked at 2200 kg/ha (consolidated) and an additional portion will be restocked at 1,100 kg/ha (control). At stocking brood fish from each treatment will be stocked into 0.1 ha spawning ponds, with 6 replicate ponds per treatment at a sex ratio of 1:1 will be used for both treatments. In all trials, spawning cans will be placed in each pond on April 1 and cans will be checked for spawns through mid-July. Spawns will be taken to the hatchery, weighed, sampled to determine number of eggs, and placed in a hatching tank. At hatch, fry will be enumerated volumetrically and the percent hatch will be determined for each spawn. Treatments will be compared for number of spawns, weight of spawns, percent hatch, average date of spawn, and survival of broodfish. DNA markers will be used to determine parentage of spawns. Economic analysis will determine relative cost/benefits for treatments in each trial.
The project is in its first year and effects of female to male ratio on channel catfish spawning success is being evaluated. Channel catfish broodfish were stocked at female to male ratios of 1 to 1 and 4 to 1. Spawns are currently being collected. Although data collection is not yet complete, initial data indicate approximately twice as many females spawned in the 1 to 1 female to male treatment as in the 4 to 1 female to male ratio treatment.