Event Title

Session D3 - Lessons from a comprehensive survey of a fish pass by a digital video system in the Reuss River

Presenter Information

Armin Peter, SCHAGER Eva

Location

UMass Amherst

Event Website

http://fishpassage.ecs.umass.edu/Conference2012/

Start Date

5-6-2012 3:25 PM

End Date

5-6-2012 3:45 PM

Description

The Reuss River in the City of Lucerne (Switzerland) is the regulated outflow from Lake Lucerne. A run-of-river hydropower plant (annual production 4.3 millions GWh) was completed in 1998 on the right river shore. In order to facilitate upstream migration of fishes a fish pass (vertical-slot) with an observation window was included in the fish ladder. The discharge of the fish pass is 800 l/s. The purpose of the fish pass is to ensure migrations between Lake Lucerne and the Reuss River. In order to study the fish migrations we installed a digital video camera system and observed the fish through the observation window. We observed the fishes during a long period over three years. The camera was running during the day, but on selected periods also at night when we installed a light in the fish pass. A total of 72000 individuals were registered and analyzed in the three years. Surprisingly we could not only observe upstream migrating fish but also individuals which migrated in the downstream direction. The most common observed fishes were chub (Squalius cephalus), barbel (Barbus barbus) and brown trout (Salmo trutta fario). These three species contributed to 88 % of all observations. A total of 11 species was observed in the ladder. However in the down- and upstream part of the Reuss River 28 fish species can be found. Some of them in very low densities. The video observations documented that the fish pass was not only used as a migration corridor, but also as habitat, reproduction and feeding area. Most fish species showed seasonal migration patterns. In June and July we observed the highest migration activities. But also in October there was a clear peak in the migration activities. Most of the cyprinid species stopped the activity in winter (December-March). Brown trout did not show any seasonal migration patterns. The advantage and disadvantage of video analysis in fish ladders will be discussed. The observation system is very reliable and works very well in clear water under non-turbulent flow conditions, but video observations have also certain limits. The comprehensive study demonstrated that the fish passage is working very well for some specific species. On the other hand no migration observations were made for other species which may have problems with the hydraulic conditions of the fish pass or with the entrance. This is mainly true for the grayling (Thymallus thymallus) and the nase (Chondrostoma nasus), two sentinel species in the River Reuss. The broad analyses with observations over three years help to identify deficits with the fish passage and necessary improvements for the future.

Comments

Armin Peter studies in biology at ETH Zurich, PhD thesis on trout population dynamics and trout stocking, post doc at the University of British Columbia, Vancouver B.C., Canada, senior reserach scientist at Eawag, Switzerland. Research focus: fish migration, fish habitat, river restoration.

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Jun 5th, 3:25 PM Jun 5th, 3:45 PM

Session D3 - Lessons from a comprehensive survey of a fish pass by a digital video system in the Reuss River

UMass Amherst

The Reuss River in the City of Lucerne (Switzerland) is the regulated outflow from Lake Lucerne. A run-of-river hydropower plant (annual production 4.3 millions GWh) was completed in 1998 on the right river shore. In order to facilitate upstream migration of fishes a fish pass (vertical-slot) with an observation window was included in the fish ladder. The discharge of the fish pass is 800 l/s. The purpose of the fish pass is to ensure migrations between Lake Lucerne and the Reuss River. In order to study the fish migrations we installed a digital video camera system and observed the fish through the observation window. We observed the fishes during a long period over three years. The camera was running during the day, but on selected periods also at night when we installed a light in the fish pass. A total of 72000 individuals were registered and analyzed in the three years. Surprisingly we could not only observe upstream migrating fish but also individuals which migrated in the downstream direction. The most common observed fishes were chub (Squalius cephalus), barbel (Barbus barbus) and brown trout (Salmo trutta fario). These three species contributed to 88 % of all observations. A total of 11 species was observed in the ladder. However in the down- and upstream part of the Reuss River 28 fish species can be found. Some of them in very low densities. The video observations documented that the fish pass was not only used as a migration corridor, but also as habitat, reproduction and feeding area. Most fish species showed seasonal migration patterns. In June and July we observed the highest migration activities. But also in October there was a clear peak in the migration activities. Most of the cyprinid species stopped the activity in winter (December-March). Brown trout did not show any seasonal migration patterns. The advantage and disadvantage of video analysis in fish ladders will be discussed. The observation system is very reliable and works very well in clear water under non-turbulent flow conditions, but video observations have also certain limits. The comprehensive study demonstrated that the fish passage is working very well for some specific species. On the other hand no migration observations were made for other species which may have problems with the hydraulic conditions of the fish pass or with the entrance. This is mainly true for the grayling (Thymallus thymallus) and the nase (Chondrostoma nasus), two sentinel species in the River Reuss. The broad analyses with observations over three years help to identify deficits with the fish passage and necessary improvements for the future.

http://scholarworks.umass.edu/fishpassage_conference/2012/June5/39