Location

Groningen, The Netherlands

Event Website

http://fishpassage.umass.edu/

Start Date

23-6-2015 2:45 PM

End Date

23-6-2015 3:00 PM

Description

Abstract:

For the fish bypass at the Danubehydropower station Wien/Freudenau the functioning as migration facility has been classified as functional after construction in 1997. The importance of habitat support for the lifecycles of Danube fish species becomes clearly visible in times when degraded, impounded, current speed reduced section of the river are dominating the fluvial ecosystem. Central parts of impounded areas are not supporting all the needs of riverine fish: Gravel-spawning grounds, suitable flow velocity and diverse 0+ fish habitats are missing. Upper most part of impoundments, tributaries and artificial rivers, like fish bypass systems, can function as essentially needed last habitats.

The fish bypass system of Wien/Freudenau has a length of 1.6 km and a discharge of at least 1.5 m³. 2/3 of the system has been constructed as a near-natural circumvention stream and 1/3 as a nature-like pool pass. After 15 years of operation it becomes clearly visible that fish use the bypass system as spawning ground extensively and therefore it can make an important contribution for the maintenance of several endangered species, like the nase (Chondrostoma nasus) and the barbel (Barbus barbus). In the present study a monitoring was conducted throughout a year. Seasonal changes in abundances, species diversity and spawning events were observed. A total of 35 species colonize the bypass with temporary and spatial fluctuations. In early spring (February and March), the indicator species of the free flowing Danube, nase and barbel, migrated into the fish pass in very high quantities. After spawning in April and May the adults disappeared and a few weeks later thousands of young-of-theyear were observed. The present data show, that the chosen natural like solution of a bypass system serves in contrast to a hard technical construction, - additionally to its migration function - like a Danube tributary of the grayling zone. 23 species of young-of-theyear fish classes’ inhabited the system in 2014. Some of them have been proved in larval stages by barcoding.

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Jun 23rd, 2:45 PM Jun 23rd, 3:00 PM

Session B5: The Danube Fish Bypass System of Vienna/Freudenau and its Importance as a Lifecycle Habitat

Groningen, The Netherlands

Abstract:

For the fish bypass at the Danubehydropower station Wien/Freudenau the functioning as migration facility has been classified as functional after construction in 1997. The importance of habitat support for the lifecycles of Danube fish species becomes clearly visible in times when degraded, impounded, current speed reduced section of the river are dominating the fluvial ecosystem. Central parts of impounded areas are not supporting all the needs of riverine fish: Gravel-spawning grounds, suitable flow velocity and diverse 0+ fish habitats are missing. Upper most part of impoundments, tributaries and artificial rivers, like fish bypass systems, can function as essentially needed last habitats.

The fish bypass system of Wien/Freudenau has a length of 1.6 km and a discharge of at least 1.5 m³. 2/3 of the system has been constructed as a near-natural circumvention stream and 1/3 as a nature-like pool pass. After 15 years of operation it becomes clearly visible that fish use the bypass system as spawning ground extensively and therefore it can make an important contribution for the maintenance of several endangered species, like the nase (Chondrostoma nasus) and the barbel (Barbus barbus). In the present study a monitoring was conducted throughout a year. Seasonal changes in abundances, species diversity and spawning events were observed. A total of 35 species colonize the bypass with temporary and spatial fluctuations. In early spring (February and March), the indicator species of the free flowing Danube, nase and barbel, migrated into the fish pass in very high quantities. After spawning in April and May the adults disappeared and a few weeks later thousands of young-of-theyear were observed. The present data show, that the chosen natural like solution of a bypass system serves in contrast to a hard technical construction, - additionally to its migration function - like a Danube tributary of the grayling zone. 23 species of young-of-theyear fish classes’ inhabited the system in 2014. Some of them have been proved in larval stages by barcoding.

https://scholarworks.umass.edu/fishpassage_conference/2015/June23/14