Journal of NACAA

Cold Tolerance of Blue Tilapia (Oreochromis aureus) Stocks in South Carolina

ISSN 2158-9429

Volume 10, Issue 1 - June 2017

Editor: Bindu Poudel-Ward

Abstract

Blue tilapia (Oreochromis aureus Steindachner) have been stocked in water bodies for control of nuisance aquatic vegetation and as food for predators. Overwintering and reproducing blue tilapia pose potential risks for aquatic systems through alteration of nesting habitats, food resources, and aquatic plant communities. To evaluate the potential for overwintering, the overall objective of this study was to measure the cold tolerance of blue tilapia stocks currently cultured in South Carolina. Experiments were conducted with fingerling fish (38 – 54 mm) exposed to declining water temperatures, where water temperatures were reduced by 2°C at 24 hour intervals. Temperature decreases continued until 100% mortality was observed. Trials indicated the lethal temperature for 50% of the population (LT₅₀) was approximately 8.8° C.  Complete mortality of fingerling tilapia were observed at water temperatures of 6° C. Mean water temperatures (8.9 - 20.6° C) in coastal South Carolina during the winter of 2014 – 2015 indicate there is potential for naturalization of blue tilapia. Pond managers and government agencies are encouraged to thoroughly evaluate the potential risk for tilapia escapes when selecting blue tilapia for use in their coastal impoundments, as the potential for naturalization is evident.