Potential for naturalization of nonidigenous tilapia Orechromis sp. in coastal louisiana marshes based on integrating thermal tolerance and field data

Document Type

Article

Publication Date

8-1-2012

Abstract

In the spring of 2009, tilapia Orechromis sp. were discovered in waterways near Port Sulphur, Louisiana. The potential naturalization of this population is of great concern as this invasive species can drastically disrupt fish community structure. Identification as an Oreochromis hybrid occurred through allozyme analysis, and our project investigated tilapia thermal tolerances at environmentally relevant salinities to determine lethal limits. In the laboratory, tilapia were acclimated for 1 month at salinities of 0.8, 7.0, or 15.0 ppt (g/L). Initial water temperatures of 26 C were decreased 2 C per day for all three acclimation salinities and 1 C per day for a cohort acclimated at 7 ppt until 100 % mortality of tilapia was observed. Tilapia acclimated to salinities of 0.8 and 7 ppt lost equilibrium at 10 C, while 15.0 ppt-acclimated individuals lost equilibrium at 8 C. Mortality within all acclimation salinities occurred between 8 and 6 C, with median lower lethal temperatures for all acclimations calculated between 6.0 and 6.6 C. Salinity acclimation prior to the thermal tolerance challenge did not alter cold tolerance. Experimental data were statistically modeled with field temperature data, and our results suggest low potential for tilapia naturalization, except in developed areas. © Society of Wetland Scientists 2012.

Publication Source (Journal or Book title)

Wetlands

First Page

717

Last Page

723

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