Will channel catfish select themselves for artificial spawning?

Hybrid-catfish fingerling production is reliant upon artificial spawning practices that select female fish ready to ovulate.  We evaluated a system designed to concentrate female catfish and determined whether the system selected fish more likely to ovulate.  Mesh fencing separated the shallow end from deeper end in this preliminary study.  Two points in the pond barrier permitted one-way fish travel from the deep to the shallow end of the pond.  We stocked 50 female fish into the deep ends of both ponds.  Caged male channel catfish were placed across the barrier in one pond.  After 10 days, the ponds were seined, the number of female fish crossing the barrier tallied, and a sub-sample of these fish injected with carp pituitary extract to induce spawning.  A larger proportion of females crossed the barrier in the pond containing males; these females ovulated at higher rates than females held with no males.  In both ponds, females crossing the barrier ovulated at slightly higher rates than fish that failed to cross.  This approach was able to concentrate catfish and provide marginal increases in ovulation rates among graded fish.  We are currently adapting this technique to include a means of ‘seine-less’ capture with more testing scheduled.