SEASONAL VALUES OF SELECTED BLOOD PARAMETERS OF FARM-RAISED CHANNEL CATFISH (ICTALURUS-PUNCTATUS) IN THE MISSISSIPPI DELTA

Hematocrit, sodium, chloride, potassium, calcium, glucose, and pH were measured in whole blood of 1,522 channel catfish collected from 3 com mercial food-fish ponds in the Mississippi Delta. Samples were collect ed from March 1995 to March 1996 to monitor seasonal fluctuations. A t otal of 10-20 fish were arbitrarily collected with snag lines from eac h pond on each sample day. The mean monthly hematocrits fluctuated sea sonally from a low of 14.5% in midwinter to a high of 25.7% in midsumm er (annual (x) over bar = 21%, SE = 0.15). Sodium levels were consiste nt throughout the year with a mean (SE) of 134 (0.13) mM/liter. Mean c hloride values for the year were 120 (0.14) mM/liter but increased to 132 mM/liter in midwinter. By March 1996, the chloride levels had retu rned to levels observed during spring 1995. Potassium and glucose leve ls varied throughout the year with means of 4.43 (0.06) mM/liter and 2 6.9 (0.46) mg/dl, respectively, and coefficients of variation of 51.8% and 63.3%, respectively. Calcium and pH values were fairly stable wit h means of 1.31 (0.004) mM/liter and 7.13 (0.004), respectively. All p arameters except glucose and potassium may be adequately evaluated wit h a sample size of 25 or less. These data were collected to provide ba seline information for ongoing pond health studies.