Reducing Size Variation in Hybrid Catfish Culture through Graded Partial Harvest

Abstract

AbstractHybrid catfish (female Channel Catfish Ictalurus punctatus × male Blue Catfish I. furcatus) have quickly become a major contributor to ictalurid catfish aquaculture in the United States. Hybrid catfish have unique production characteristics compared with Channel Catfish, and rapid adoption of the hybrid by fish farmers has outpaced research on appropriate management practices. This study was conducted to determine the effect of midsummer partial harvest of faster‐growing fish on production characteristics in ponds with hybrid catfish in single‐batch culture. Twelve 1.0‐acre ponds were stocked with 10,000 year‐class 1 hybrid catfish (~0.12 lb/fish) in mid‐March 2015. In August 2015, six random ponds were partially harvested to remove fish larger than ~1.25 lb using an in‐pond, flexible‐panel, grading sock. In October 2015, all ponds were completely harvested. Partial harvest of faster‐growing fish removed ~26% of fish from ponds in August. Removal of faster‐growing fish resulted in 0.9% of the total crop considered “out‐of‐size” (>4 lb/fish) and subject to discounts, compared with 2.1% of the fish from the control ponds. However, reduction of fish numbers by midsummer partial harvest reduced overall production by an average of 16% in the partial‐harvest treatment compared with control ponds. Overall, partial harvest of faster‐growing fish in midsummer reduced the overall biomass of discounted, out‐of‐size fish. Higher production in control ponds resulted in greater net revenue.