Stress Effects in Channel Catfish (Ictalurus punctatus) Fry on Pond Survival

Authors: Booth, Natha; Peterson, Brian

Submitted to: Catfish Farmers of America Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 12/20/2008
Publication Date: 3/5/2009
Citation: Booth, N.J., Peterson, B.C. 2009. Stress Effects in Channel Catfish (Ictalurus punctatus) Fry on Pond Survival. Catfish Farmers of America Annual Meeting.

Interpretive Summary:

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 a pool of three families were divided into two groups. One group was physically stressed daily with a rigorous exercise program for 14 days, while the other was left undisturbed except for routine feeding. Whole body cortisol measurements were taken at Day 0, 7, and 14 in both the stressed fish and the un-treated controls immediately following the “exercise” protocol. 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. There were no significant differences in the weight of the fish at transfer to ponds. Cortisol measurements were significantly higher in the stressed fish on the first day, but by day 7, and on day 14, the fish had apparently adapted to the stress and the cortisol levels were the same as the unstressed fish. 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. Interestingly, while the survival of the two groups was the same after 21 days in the ponds, the fish that had been stressed prior to transfer to ponds gained 23% more weight during the pond period than did the unstressed fish. 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. Stress has long been considered to have a negative effect on fish fry, but this study indicates that some types of stress may actually be beneficial. Future studies will examine the ability of catfish fry to adapt to stress and will evaluate the application of “exercise” regimens to enhance fry to fingerling survival in ponds.