Early Registration Deadline
12 February 2010

Travel Award & Grant Recipients Notified
March 2010

Authors Notified
April 2010

Schedule Posted
January 2010

Vimos, D. ., Laboratorio de Ecología Acuática. Universidad San Francisco. , Quito, Ecuador, diego_v02@yahoo.com
Encalada, A. ., Laboratorio de Ecología Acuática. Universidad San Francisco. , Quito, Ecuador, aencalada@usfq.edu.ec
Ríos, B. ., Laboratorio de Ecología Acuática. Universidad San Francisco. , Quito, Ecuador, brios@ub.edu
Ordoñez, V. ., Laboratorio de Ecología Acuática. Universidad San Francisco. , Quito, Ecuador, sire_ordonez@hotmail.com
Prat, N. ., Departamento de Ecología, Universidad de Barcelona, Barcelona, Spain, nprat@ub.edu

EFFECTS OF INTRODUCED RAINBOW TROUT (ONCORHYNCHUS MYKISS) AND BROWN TROUT (SALMO TRUTTA) IN ANDEAN STREAM COMMUNITIES

The introduction of trout, its establishment, and potential impacts on aquatic ecosystems are poorly understood in South America. We studied the abundance of trout (Salmo trutta and Oncorhynchus mykiss) in high-altitude Andean streams in northern Ecuador, and surveyed its potential impacts on macroinvertebrate and algal communities. Trout density varied greatly among the 16 streams surveyed. Our results suggest that the impacts of trout in macroinvertebrate and algal communities is minor, as reflected in the lack of relationships between trout density in one hand, and invertebrate density and algal productivity in the other. These parameters seem to depend more on the characteristics of terrestrial and riverine habitats, and the presence of organic inputs from surrounding areas (i.e. cattle raising).Gut content analysis revealed that medium-sized trout ingest the highest proportion of aquatic macroinvertebrates, Anomalopsychidae and Chironomidae being the most frequent prey. Although we did not find a clear influence of trout on the structure of invertebrate and algal communities, they might have an impact on the behavior and morphological responses of aquatic biota. More studies on these indirect effects are needed.

Poster presentation

Session #:T34
Date: 06-08-10
Time: 17:30 - 19:30

Presentation is given by student: No