Event Title

Session C1: Prioritizing Efforts to Restore Habitats and Longitudinal Connectivity for the Rehabilitation of the European Sturgeon (Acipenser Sturio) in a German Lowland River

Location

Groningen, The Netherlands

Event Website

http://fishpassage.umass.edu/

Start Date

22-6-2015 11:25 AM

End Date

22-6-2015 11:40 AM

Description

Abstract:

This study focused on assessing the rehabilitation potential of the Spree-Havel River system for rheophilic and anadromous fish species using the European sturgeon Acipenser sturio as indicator species. An age-structured population model for the sturgeon was set up to predict the potential effects of different river rehabilitation scenarios on the population development.

The scenarios included: 1) solely the provision of longitudinal connectivity without further habitat enhancements, 2) providing longitudinal connectivity in combination with moderate gravel addition and modified flow conditions below weirs, and 3) providing longitudinal connectivity in combination with significant riverbed modifications to create spawning habitats. All three scenarios have been calculated for four adjacent river segments of in total

220 km length allowing for cumulative assessments. The main aim of this simulation study was to identify the best solution for the combination of habitat enhancement and connectivity measures to achieve the maximum ecological improvement of riverine fish assemblages at feasible efforts.

Restoration of river connectivity is the main prerequisite for the re-establishment of a variety of diadromous species including sturgeon, but by itself it will have little potential to support their populations. At least moderate improvements of the hydro-morphology and habitat structures (restoring about 30% of the potential habitats will result in 30,000 m² spawning habitat) will be essential for the long-term success. This rehabilitation in conjunction with longitudinal connectivity over the 220 km long river course will dramatically increase the population potential. As a result, the sturgeon population of the Havel-Spree river system could contribute an estimated share of 41% to a potential sturgeon stock of the River Elbe catchment (148,268 km²), accounting for 15,400-42,000 juvenile fish annually recruiting from the system and an annual return of 4,300-11,700 spawners.

Comments

Presenting Author Bio:

Christian Woltzer performs research on fish assemblages of large rivers for more than 20 years. Research interests cover primarily structuring factors, fish assemblage dynamics, functional traits and process-based fish environment interactions as well as river rehabilitation, connectivity and fish-based environmental assessments.

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Jun 22nd, 11:25 AM Jun 22nd, 11:40 AM

Session C1: Prioritizing Efforts to Restore Habitats and Longitudinal Connectivity for the Rehabilitation of the European Sturgeon (Acipenser Sturio) in a German Lowland River

Groningen, The Netherlands

Abstract:

This study focused on assessing the rehabilitation potential of the Spree-Havel River system for rheophilic and anadromous fish species using the European sturgeon Acipenser sturio as indicator species. An age-structured population model for the sturgeon was set up to predict the potential effects of different river rehabilitation scenarios on the population development.

The scenarios included: 1) solely the provision of longitudinal connectivity without further habitat enhancements, 2) providing longitudinal connectivity in combination with moderate gravel addition and modified flow conditions below weirs, and 3) providing longitudinal connectivity in combination with significant riverbed modifications to create spawning habitats. All three scenarios have been calculated for four adjacent river segments of in total

220 km length allowing for cumulative assessments. The main aim of this simulation study was to identify the best solution for the combination of habitat enhancement and connectivity measures to achieve the maximum ecological improvement of riverine fish assemblages at feasible efforts.

Restoration of river connectivity is the main prerequisite for the re-establishment of a variety of diadromous species including sturgeon, but by itself it will have little potential to support their populations. At least moderate improvements of the hydro-morphology and habitat structures (restoring about 30% of the potential habitats will result in 30,000 m² spawning habitat) will be essential for the long-term success. This rehabilitation in conjunction with longitudinal connectivity over the 220 km long river course will dramatically increase the population potential. As a result, the sturgeon population of the Havel-Spree river system could contribute an estimated share of 41% to a potential sturgeon stock of the River Elbe catchment (148,268 km²), accounting for 15,400-42,000 juvenile fish annually recruiting from the system and an annual return of 4,300-11,700 spawners.

https://scholarworks.umass.edu/fishpassage_conference/2015/June22/12