Kenneth O. Allen

Laboratory tests were conducted to determine the effect of salinity on growth and survival of channel catfish, Ictalurus punctatus. Three-day old or older eggs tolerated up to 16 ppt total salinity. However, at the time of hatching there was a sharp drop in tolerance to about 8 ppt. This level of tolerance was maintained during the period of yolk absorption. Following yolk absorption there was an increase in tolerance to about 9 or 10 ppt. By five months of age tolerance had increased to 11 ppt and to 12 ppt by six months. The level of tolerance was about the same at 11-14 months...

Two lots of the Arkansas strain of cha.nnel catfish, Ictalurus punctatus, containing both albino and ngrmal fish, were acclimated in the laboratory at a constant temperature of 30.0 C. Samples of albino and normal fish were exposed to a lethal temperature of 39.0 o C. The albinos from both lots had the highest mean survival time, but the differences were not statistically significant.

Three lots of 6-day-old to IPh-month-old channel catfish from a common initial source but reared under different thermal conditions were utilized to investigate several heat-tolerance relationships. During the experimental period the fish were held in constant-temperature tanks and samples of fish were subjected to a range of sub-lethal and lethal temperatures in test baths. The results were studied by plotting time to death of individual fish and means of test samples on semi-log paper, probability paper in some instances, and subjecting pertinent data to statistical analysis....