Location: Warmwater Aquaculture Research UnitTitle: Effects of hatching conditions on triple tail deformity in channel catfish Author
Submitted to: Aquaculture America Conference
Publication Type: Abstract Only
Publication Acceptance Date: 11/10/2011
Publication Date: 2/28/2012
Citation: Ott, B.D., Torrans, E.L. 2012. Effects of hatching conditions on triple tail deformity in channel catfish. Aquaculture America Conference. P.348.
Technical Abstract: Channel catfish (Ictalurus punctatus) occasionally will be found with abnormal caudal fin structures. These deformities vary in size and appearance but generally occur as an extra fin protruding from the lateral surface of the caudal peduncle. The phrase “triple-tail” is often used to describe fish with these fin irregularities. Observations from previous hatching seasons suggests that low DO concentrations during incubation can result in premature hatching and impact the presence of the triple-tail defect. The current study was conducted to determine if premature hatching or damage to the chorion contribute to the incidence of triple-tail deformities. Channel catfish eggs were incubated and hatched using one of three treatments; control, punctured chorion, and 24-h premature hatch. The control treatment was incubated and allowed to hatch under standard hatchery conditions. The punctured chorion treatment had individual egg chorions punctured with a hypodermic needle and then allowed to hatch naturally. For the premature hatch treatment, a portion of the egg mass was placed in a beaker without supplemental aeration at approximately 24-h before anticipated hatch and as oxygen was depleted, the fry hatched prematurely. The fry were reared for 24 weeks and examined to determine the presence of the triple-tail deformity. Those fry that hatched prematurely from low oxygen concentrations had significantly higher occurrences (73 ± 11%) of triple-tails than those hatched naturally (38 ± 8%) or those whose chorions were punctured (53 ± 10%, Figure 1). Additionally, as has been seen in previous research survival was lower in the prematurely hatched group (30 ± 9%) than those in the other two treatments (64 ± 6% for both). Poor incubation conditions (namely low oxygen concentration) may be the leading factor in the development of the triple-tail abnormality and could be improved by the addition of oxygen or better incubation practices.