February 15-18, 2009 Washington State Convention Center Seattle ...

30
STRESS EFFECTS IN CHANNEL CATFISH (Ictalurus punctatus) FRY ON POND SURVIVAL
Natha J. Booth and Brian C. Peterson
Catfish Genetics Research Unit, ARS-USDA
141 Experiment Station Rd.
P.O. Box 38
Stoneville, MS 38776 USA
natha.booth@ars.usda.gov
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.