Fish Monitoring in an Andean-Patagonian River: An Evaluation of the Effectiveness of underwater Video Stations Compared to Electrofishing.

Abstract

Monitoring fish and space use over time help us understand the processes occurring in populations and communities within the aquatic ecosystem. To carry out this monitoring, it is advisable to use methods that are not harmful to the species or the environment, avoiding disruption of the natural habitat. The upper Limay River serves as a crucial corridor for various native and exotic species. Along its course, it features diverse types of habitats in its main channel and active and temporary secondary arms throughout its course. The main objective of the study was to evaluate the performance and effectiveness of fixed underwater video stations (UVS) for conducting population monitoring and to compare this methodology with electrofishing a traditional technique used to date in the river. Forty-nine river sites were sampled, covering seven habitat types in the main channel and active and temporary secondary arms. Filming was conducted with UVS, and after 50 minutes of recording, an electrofishing was carried out. The results indicated that the video technique was more effective for species for detection species in the Limay River. Adittionally, the use of cameras improved the observation of fish assemblages. Fixed underwater video proved to be useful for fish monitoring, presenting minimal risk to the studied individuals and requiring a minimal field team.