Thermoregulatory activity in the Tecopa pupfish, Cyprindon nevadensis amargosae, an inhabitant of a thermal spring

The final thermal preferendum of Tecopa pupfish Cyprinodon nevadensis amargosae collected from a thermal spring was determined in the laboratory in spatial and temporal thermal gradients. Temperatures chosen centred around 30°C — a value close to those reported for other warmwater species in the literature. Upper limits to final preferenda and thermal tolerance in all species of fish are proposed.