Evaluation of Low Levels of Salinity on Hematological Parameters and Health Status of Channel Catfish Reared in Multiple‐Crop Ponds

• Published in: Journal of aquatic animal health 2006-03, Vol.18 (1), p.1-10
• Main Authors: O'Neal, Clifford C., Hawke, John P., Weirich, Charles R.
• Format: Article
• Language: English
• Subjects: Aeromonas; Freshwater; Ictalurus punctatus
• ISSN: 0899-7659; 1548-8667
• DOI: 10.1577/H05-005.1

A 1‐year study was conducted from February 1999 to January 2000 to determine the effects of low levels of salinity on selected hematological parameters (total protein, hematocrit, leukocrit, and osmolality) and the health of channel catfish Ictalurus punctatus reared in ponds managed under the multiple cropping production strategy. We stocked 2,000 catfish into 15 ponds (0.08 ha each) that we subdivided into five replicate ponds per each of three NaCl (salinity) treatments: freshwater conditions (nominal salinity = 0 g/L of water) or adjusted salinities of 1.5 or 3 g/L. Total protein, hematocrit, and plasma osmolality for fish reared at the NaCl‐induced salinities were significantly higher than those for fish cultured in freshwater. Although the leukocrit of fish reared at a salinity of 3 g/L was significantly higher than that of fish reared in freshwater or at 1.5 g/L, all were within the normal ranges reported for channel catfish. Although two bacterial diseases known to routinely affect channel catfish (enteric septicemia of catfish and motile aeromonad septicemia) were observed at all salinity levels tested, columnaris disease was not observed during the study. Parasitic infections during certain months were less severe for fish reared in saline ponds than in freshwater. The results indicate that the hematological variables measured in this study were higher at increased salinities but within the ranges reported as normal for channel catfish.