Location: Warmwater Aquaculture Research Unit
Title: The see-saw a vertical-lift incubator designed for channel catfish egg masses Authors
Submitted to: Catfish Farmers of America Research Symposium
Publication Type: Abstract Only
Publication Acceptance Date: December 16, 2011
Publication Date: February 16, 2012
Citation: Torrans, E.L., Ott, B.D., Jones, R., Jones, R. 2012. The see-saw a vertical-lift incubator designed for channel catfish egg masses. Catfish Farmers of America Research Symposium. P.16. Technical Abstract: Channel catfish egg masses are typically incubated in baskets that are suspended in water that is agitated with rotating or oscillating paddles. We designed and tested a new vertical-lift incubator (the “See-Saw”) to incubate channel catfish egg masses. Preliminary research in commercial hatcheries demonstrated that when loaded with eggs at higher than recommended rates, as often occurs during the peak of the spawning season, survival to swim-up stage was significantly (2.3 x) higher in the See-Saw than in the traditional troughs. Research in the last two years which is presented here has focused on maximizing per-trough loading rates for the See-Saw. In 2010 we loaded See-Saws (five troughs per treatment) with 15.0 ± 0.1 lbs (220,300 eggs), 30.1 ± 0.1 lbs (447,000 eggs), 45.1 ± 0.1 lbs (669,600 eggs), and 60.1 ± 0.0 lbs (893,100 eggs) of spawns per trough. Water flow averaged 2.1 gpm, roughly half the rate recommended for paddle-type incubators. Swim-up fry production increased proportionally to stocking density, with the 15, 30, and 45 lb troughs producing 132,700, 263,800, and 429,400, respectively (see figure at right). However, the 60 lb treatment only produced 417,200 swim-up fry. Survival to swim-up in the 15, 30, and 45 lb treatments averaged 60 ± 9%, 59 ± 6%, and 64 ± 4%, respectively, similar to values reported in commercial hatcheries (60%), but survival in the 60 lb treatment was only 46 ± 8%. In 2011 we examined the effect of oxygen supplementation on troughs loaded with 45 lbs of eggs. Fifteen troughs were incubated using no oxygen supplementation and had a mean oxygen saturation of 82.4%; 17 troughs were incubated using additional oxygen added through ceramic diffusers at an average rate of 0.12 liters/min resulting in an average oxygen saturation of 124.1%. Mean swim-up fry production overall was 462,363 fry/trough (10,327 fry/lb eggs), for a survival from egg to swim-up of 71.2%. There were no significant differences between treatments, confirming that 45 lbs of eggs can be incubated per See-Saw trough without additional oxygen if the hatchery water supply is near air saturation. We believe that even higher loading densities could be incubated using supplemental oxygen with no impact on hatch rate or survival to swim-up stage. The See-Saw incubator can incubate 3-4 x as many eggs as traditional paddle-type incubators using half the water, a tremendous savings in both floor space and energy use.