Susceptibility of native perca (Percichthys trucha) and exotic rainbow trout (Oncorhynchus mykiss) to high temperature in Patagonia: different physiological traits and distinctive responses

JUANA AIGO ; MARÍA EUGENIA LATTUCA; VÍCTOR CUSSAC

HYDROBIOLOGIA

SPRINGER

Lugar: Berlin; Año: 2014 vol. 736 p. 73 - 82

0018-8158

The aim of this work was obtaining causal evidence for the observed decrease of relative abundances of exotic rainbow trout (Oncorhynchus mykiss) and the increase of native perca (Percichthys trucha) regarding increasing temperature, in Patagonia. We conducted an experimental study on the thermal preferences of juvenile perca and rainbow trout collected in three sites. We characterized the relationship between preferred temperature (PT) and acclimation temperature (AT) for perca and rainbow trout and analyzed between-sites variations in PTs. Both species responded with increasing PT to higher AT, but with differences in overall PT for perca coming from different sites (lower PTs for fish from cooler lake). In general, rainbow trout displayed lower PT and a narrower range of PT than perca. Our results provide the first comparative view of PTs of one important native fish species and the main sport fish species of Patagonia. Native perca may be better equipped to cope with warmer waters than exotic rainbow trout, in agreement with the geographic distribution of perca as compared to rainbow trout. Also, perca may have an advantage at the local level, particularly in littoral areas of lakes, through the alleviation of predation by and trophic competition with trout.