Reducing Size Variation in Hybrid Catfish Culture through Graded Partial Harvest

Abstract

Hybrid 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.

Received May 12, 2016; accepted August 8, 2016 Published online December 6, 2016

ACKNOWLEDGMENTS

This work was supported by the Mississippi Agricultural and Forestry Experiment Station (MAFES), Mississippi State University, under MAFES Project MIS-371592 and U.S. Department of Agriculture, Agricultural Research Service CRIS 6016066200(340), Project Water Quality 6066-13320-005-000. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the authors and do not necessarily reflect the view of Mississippi State University or the U.S. Department of Agriculture. Mention of trade names is for descriptive purposes only and does not imply endorsement or approval by the U.S. Department of Agriculture or Mississippi State University to the exclusion of other products that may also be suitable.