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ARS Home » Southeast Area » Stoneville, Mississippi » Warmwater Aquaculture Research Unit » Research » Publications at this Location » Publication #253828
Title: Effect of Increased Egg Stocking Density in Existing and Experimental Catfish Incubators

Author
item Ott, Brian
item Torrans, Eugene

Submitted to: Southeastern Association of Fish and Wildlife Agencies Conference
Publication Type: Proceedings
Publication Acceptance Date: 7/29/2010
Publication Date: 3/1/2011
Citation: Ott, B.D., Torrans, E.L. 2011. Effect of Increased Egg Stocking Density in Existing and Experimental Catfish Incubators. Southeastern Association of Fish and Wildlife Agencies Conference. 54:131-135.

Interpretive Summary: Channel catfish egg masses are typically incubated in stationary wire mesh baskets suspended across metal troughs with flow-through water that is agitated and circulated between the baskets and around the eggs with rotating paddles. A new vertical-lift incubator (the “See-Saw”) was tested for incubating channel catfish egg masses. Racks were placed inside adjacent hatchery troughs with three hinged-lid baskets held in each rack. The racks were connected to overhead bars that moved up and down, raising the rack in one trough while lowering the rack in the adjacent trough. Egg masses were placed inside the baskets and moved in and out of the water column as the racks moved through the cycle. Both the See-Saw and standard troughs were loaded with 1.5-2.0x more egg masses than recommended loading rates. Fry survival was 2.3x higher for the See-Saw than the standard troughs. Use of the See-Saw hatchery increases fry survival while simultaneously using less water and hatchery space per unit fry produced.

Technical Abstract: Channel catfish egg masses are typically incubated in stationary wire mesh baskets suspended across metal troughs with flow-through water that is agitated and circulated between the baskets and around the eggs with rotating paddles. A limiting factor in the successful incubation of channel catfish egg masses is the absorption of oxygen by the developing embryos; low levels of dissolved oxygen in the water result in premature hatching and increased fry mortality. We designed and tested a vertical-lift incubator (the “See-Saw”) for incubating channel catfish egg masses. Angle-aluminum racks were placed inside paired adjacent hatchery troughs with three hinged-lid baskets held in each rack. The racks were connected to overhead bars that moved up and down at six cycles per minute, raising the rack in one trough while lowering the rack in the adjacent trough. Egg masses were placed inside the baskets and moved in and out of the water column as the racks moved through the cycle. Both the See-Saw and control troughs were loaded with 26 egg masses (13.2 kg) per trough which is 1.5-2.0x higher than recommended loading rates. Swim-up fry survival was 2.3-fold higher for the See-Saw than the control troughs. Many of the sac-fry produced in the control troughs were either dead when removed or died prior to reaching swim-up stage, presumably due to oxygen stress. Use of the See-Saw hatchery increases fry survival while simultaneously using less water and hatchery space per unit fry produced.