Author
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Torrans, Eugene |
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Submitted to: Global Aquaculture Advocate
Publication Type: Trade Journal Publication Acceptance Date: 12/9/2011 Publication Date: 1/10/2012 Citation: Torrans, E.L. 2012. Blue catfish outproduce channel catfish under low D.O. conditions. Global Aquaculture Advocate. 46-47. Interpretive Summary: Growth and production of blue and channel catfish were compared over a range of morning dissolved oxygen (DO) concentrations. Blue catfish appear to perform slight better than channel catfish at low (1.5-3.0 mg/L) DO concentrations and appear to have reasonable potential as an alternative food fish species. Technical Abstract: Blue catfish (Ictalurus furcatus) have several advantages over channel catfish (I. punctatus) as commercial culture fish. They are more resistant to ESC, PGD, and CCVD, major diseases of channel catfish. They are very easy to seine, with a near-total harvest possible with one seine haul, and may exhibit more uniform growth. They have a greater carcass yield (headed, gutted, skinned) than channel catfish, although they do yield a smaller shank filet. Perhaps the biggest perceived disadvantage is the reported poorer tolerance of low dissolved oxygen (DO) by blue catfish; however, this assessment has been based largely on anecdotal evidence. Studies were conducted in 15 1-acre and/or six ¼-acre ponds over four different years to determine the effect of low DO concentration on the feed consumption and other production parameters of blue catfish (BC) compared to channel catfish (CC). The oxygen treatments were based on the mean minimum DO concentration during the growing season (June-September). Control ponds in each study were maintained with a minimum DO concentration above 4.3 mg/L; test ponds were maintained at 1.6 – 3.0 mg/L in different studies (see figure). The fish were fed once daily to apparent satiation in all studies. Ponds were clean harvested at the end of the growing season. The results indicate that low DO has less of an impact on the feed consumption and other production parameters of BC than CC. At a mean minimum DO concentration of 1.7 mg/L, feed consumption of CC was reduced by 45%; at 1.6-1.7 mg/L, feed consumption of BC was reduced by only 21%. Behavior may play a larger role than physiology in the perceived differences in the species. The data indicates that blue catfish may have more potential as a commercial food fish than previously thought. |
