Event Title

Session D4: Improving the Use of Fish Lift by Eels and Medium-Sized Cyprinid Species

Location

Groningen, The Netherlands

Event Website

http://fishpassage.umass.edu/

Start Date

23-6-2015 12:05 PM

End Date

23-6-2015 12:30 PM

Description

Abstract:

Different types of fishways have been implemented worldwide to mitigate the impact of dams on diadromous and potamodromous fish species. Among these, fish lifts stand as the most cost-effective mitigation measures for high dams. The present study examines fish passage through the Touvedo fish lift (River Lima, northwest Portugal) along a 2.5 year period with the goal of: i) evaluating the conditions in terms of seasonal/daily fish movements patterns and to preliminary assess the overall efficacy of the facility (pre-treatment period, 1 year); ii) implementing specific measures to improve the efficacy previously recorded (6 months) and iii) evaluating the present conditions of the facility after measure implementation (post-treatment period, 1 year). Monitoring was continuously performed by using a combination of monthly video-recording and downstream electrofishing. A total of 3389 fish were transferred by the lift during the pre-treatment period, of which 89.7% corresponded to Iberian nase (54.1%) and European eel (35.6%), which migrated mainly during summer and beginning of autumn, independently from time of day. Mean overall efficacy was higher for potamodromous cyprinid species (0.42-0.44) and lower for the eel (0.10). Differences between fish size, downstream and in the fish lift, were also noted. After implementing a set of specific measures, the post-monitoring annual period revealed a significant increase of eel abundance, which increased more than threefold (1207 to 3852 individuals), though the timing of movements remained similar as of the pre-treatment period. An overall increase in fish lift efficacy was also noted for eel (0.21) and potamodromous cyprinids (0.44-1.35). Differences in fish size also decreased. The current work revealed that the use of the Touvedo fish lift by eels and medium-sized cyprinid species can be improved by reducing the gap between retention bars in the fish lift and by improving the attraction flow at the fish entrances.

Comments

Presenting Author Bio: Freshwater ecologist with a broad experience on ecological quality assessment in rivers and reservoirs. Was involved in the implementation of Water Framework Directive in Portugal, mainly in ecological quality assessment schemes. Working since 2009 at Energias de Portugal (EDP) where is dedicated to the theme of water quality, implementation of monitoring programs and evaluation of environmental flows efficacy.

This document is currently not available here.

Share

COinS
 
Jun 23rd, 12:05 PM Jun 23rd, 12:30 PM

Session D4: Improving the Use of Fish Lift by Eels and Medium-Sized Cyprinid Species

Groningen, The Netherlands

Abstract:

Different types of fishways have been implemented worldwide to mitigate the impact of dams on diadromous and potamodromous fish species. Among these, fish lifts stand as the most cost-effective mitigation measures for high dams. The present study examines fish passage through the Touvedo fish lift (River Lima, northwest Portugal) along a 2.5 year period with the goal of: i) evaluating the conditions in terms of seasonal/daily fish movements patterns and to preliminary assess the overall efficacy of the facility (pre-treatment period, 1 year); ii) implementing specific measures to improve the efficacy previously recorded (6 months) and iii) evaluating the present conditions of the facility after measure implementation (post-treatment period, 1 year). Monitoring was continuously performed by using a combination of monthly video-recording and downstream electrofishing. A total of 3389 fish were transferred by the lift during the pre-treatment period, of which 89.7% corresponded to Iberian nase (54.1%) and European eel (35.6%), which migrated mainly during summer and beginning of autumn, independently from time of day. Mean overall efficacy was higher for potamodromous cyprinid species (0.42-0.44) and lower for the eel (0.10). Differences between fish size, downstream and in the fish lift, were also noted. After implementing a set of specific measures, the post-monitoring annual period revealed a significant increase of eel abundance, which increased more than threefold (1207 to 3852 individuals), though the timing of movements remained similar as of the pre-treatment period. An overall increase in fish lift efficacy was also noted for eel (0.21) and potamodromous cyprinids (0.44-1.35). Differences in fish size also decreased. The current work revealed that the use of the Touvedo fish lift by eels and medium-sized cyprinid species can be improved by reducing the gap between retention bars in the fish lift and by improving the attraction flow at the fish entrances.

https://scholarworks.umass.edu/fishpassage_conference/2015/June23/81