|dc.description.abstract||Galaxias platei is widespread and common in southern South America, but its ecology is poorly
documented relative to other native species, especially those of commercial importance. Galaxias platei occurs
across a large range of environmental conditions, including hydrologically isolated, high-elevation lakes.
Consequently, there were several lakes in the Patagonian region where it was the only native fish species.
Introduction of salmonids into almost all lakes in Patagonia where G. platei occurs has potentially resulted in
changes in its ecology and behaviour. Thompson Lake is a small, high-elevation lake located in the Aysen River
basin (Chile) where G. platei still occurs essentially in isolation. We collected G. platei from this lake to
characterise the ecology of the species in the absence of other native and introduced fishes. We documented age
and growth patterns from otolith analysis and characterised size- and age-specific habitat use, diet and trophic niche.
In Thompson Lake, G. platei is long-lived and grows to comparatively large size (max. age = 18 years; max.
TL = 348 mm). As it grows, it exhibits an ontogenetic niche shift in habitat use, diet and trophic niche. Large
adults are piscivorous, and they occupy deep benthic habitats. Preservation of the last few remaining lakes where
G. platei is found in isolation is an important priority for maintaining the full expression of ontogenetic niche
variation in this species||es_CL