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Tolerance of nonindigenous cichlid fishes (Cichlasoma urophthalmus, Hemichromis letourneuxi) to low temperature: laboratory and field experiments in south Florida

August 1, 2010

The cold tolerance of two non-native cichlids (Hemichromis letourneuxi and Cichlasoma urophthalmus) that are established in south Florida was tested in the field and laboratory. In the laboratory, fishes were acclimated to two temperatures (24 and 28°C), and three salinities (0, 10, and 35 ppt). Two endpoints were identified: loss of equilibrium (11.5–13.7°C for C. urophthalmus; 10.8–12.5°C for H. letourneuxi), and death (9.5–11.1°C for C. urophthalmus; 9.1–13.3°C for H. letourneuxi). In the field, fishes were caged in several aquatic habitats during two winter cold snaps. Temperatures were lowest (4.0°C) in the shallow marsh, where no fish survived, and warmest in canals and solution-holes. Canals and ditches as shallow as 50 cm provided thermal refuges for these tropical fishes. Because of the effect on survival of different habitat types, simple predictions of ultimate geographic expansion by non-native fishes using latitude and thermal isoclines are insufficient for freshwater fishes.

Publication Year 2010
Title Tolerance of nonindigenous cichlid fishes (Cichlasoma urophthalmus, Hemichromis letourneuxi) to low temperature: laboratory and field experiments in south Florida
DOI 10.1007/s10530-009-9654-6
Authors Pamela J. Schofield, William F. Loftus, Robert M. Kobza, Mark I. Cook, Daniel H. Slone
Publication Type Article
Publication Subtype Journal Article
Series Title Biological Invasions
Index ID 70138842
Record Source USGS Publications Warehouse
USGS Organization Southeast Ecological Science Center