Effects of Salinity on Survival, Growth, and Nutritional Condition of Juvenile Striped Bass; Possible Environmental Factors Effecting Their Distribution in Southeastern Estuaries

Juvenile stages of striped bass (Morone saxatilis) depend on estuarine productivity for rapid growth and estuarine habitat diversity for predator protection. The distribution of juvenile striped bass within estuaries may be influenced by salinity. The potential influence of salinity on the suitability of estuaries as nursery areas was investigated in laboratory experiments using four age groups 67- and 91-d post hatch (25 C) and 112- and 133-d (28 C) post hatch of juvenile striped bass reared for 14 days at three different salinities (0, 5, and 10 ppt) representing conditions encountered in different estuarine zones of the Southeastern United States. We examined salinity effects on survival, growth rate, and nutritional condition. Nutritional condition was determined using the liver somatic index (IL), percent carcass lipid, hepatocyte cell size, and liver glycogen content. Survival exceeded 98% in all treatments. Measured parameters did not vary with salinity in any consistent pattern. Growth rates at 25 C were highest at 10 ppt, but salinity had no affect growth at 28 C. IL was unaffected by salinity at 25 C but greatest in 0 and 10 ppt at 28 C. Percent lipid was lowest at 10 ppt at 25 C, but salinity had no effect at 28 C. Salinity did not effect on hepatocyte cell size but did influence liver glycogen content at 25 C. The liver glycogen content was lowest at 5 ppt but there were no differences between 0 and 10 ppt. Our results suggest that salinity (0-10 ppt) is not critically important to the growth and condition of juvenile striped bass. Keywords: Juvenile striped bass, growth, salinity, nutritional condition

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