Submitted to: Hatchery International Magazine
Publication Type: Trade Journal
Publication Acceptance Date: 3/16/2009
Publication Date: 9/1/2009
Citation: Booth, N.J., Peterson, B.C. 2009. Some Stress Can Improve the Growth of Channel Catfish Fry. Hatchery International Magazine. September/October issue, p. 22.
Technical Abstract: Results from previous studies suggested that channel catfish (Ictalurus punctatus) fry that were housed in very high traffic areas from hatch until reaching 9 g in size were able to survive experimental challenge with Edwardsiella ictaluri better than siblings who were hatched and raised in very low traffic areas. In order to determine if physical stress in channel catfish fry could affect survival in ponds, three week old channel catfish fry from three different families were divided into two groups. One group was physically stressed daily for 14 days, while the other was left undisturbed except for routine feeding. Whole body cortisol measurements were taken at Day 0, Day 7, and Day 14 in both the stressed fish and the un-treated controls. On Day 15, the fish from individual tanks were transferred to individual cages (1.2 m by 20.3 cm cylinders) in three separate ponds where they remained for 21 days. Weights of fish from each treatment were taken at the time of transfer to cages and again at the end of 21 days. At the time of transfer to cages, the unstressed control fish were significantly higher in weight than the stressed fish (P < 0.05). There were no significant differences in final weight of the fish. Overall weight gain at the end of the study, however, was significantly higher in the stressed fish (P < 0.05). Overall percent survival for the two groups of fish was not significantly different: 97.1% and 96.7% survival for the stressed and non-stressed groups, respectively. Channel catfish fry must be able to tolerate physical stress resulting from handling during transfer from hatcheries to the ponds. This study demonstrates that channel catfish fry are able to tolerate long term physical stress with no deleterious effects, and once the stress is removed are able to grow at rates greater than that of their unstressed siblings.