Dams vs. Habitat: Predicting the effects of dams on habitat supply and juvenile rainbow trout along the Santa Cruz River, Patagonia.

QUIROGA, A.P.; LANCELOTTI, J.L.; RIVA ROSSI, C.M.; TAGLIAFERRO, M.; GARCÍA ASOREY, M.; PASCUAL, M.A.

HYDROBIOLOGIA

SPRINGER

Lugar: Berlin; Año: 2015 vol. 755 p. 57 - 72

0018-8158

Because of their remote location and lackof supporting infrastructure, large glacial rivers ofsouthern Patagonia have remained free of dams. Butthis is bound to change: two dams proposed for theSanta Cruz River would supply 16% of Argentina?shydropower and five dams planned for the Pascua andBaker Rivers could supply over 20% of Chile?shydropower. In this paper, we project the losses ofhabitat and juvenile Oncorhynchus mykiss, a recreationallyimportant species, following the constructionof the two dams in the Santa Cruz River. We applied atwo-stage fitting approach, using generalized additivemodels and generalized lineal models (GLMs) sequentiallyto describe habitat-species relationships based ondata collected through an intensive field survey of fishand environmental variables along 310 km of river. Asimplified GLM trout model based on wetted width,substrate size, and river kilometer was selected whichrepresents the observed geographic distribution verywell and with the lowest predictive error. Based on thismodel, we estimated that habitat supporting 86% ofcurrent juvenile trout production will be lost toflooding by the dams. Our data generate a rareopportunity to perform a dam impact assessment bycomparison with potential post-dam conditions.