Location
Groningen, The Netherlands
Event Website
http://fishpassage.umass.edu/
Start Date
24-6-2015 4:30 PM
End Date
24-6-2015 4:45 PM
Description
Abstract:
The effect of dams on mortality during downstream migration was simulated using distribution and mortality models in the whole Loire-Brittany water district (155 000 Km2). A combination of models was used: (1) juvenile habitats for smolts, (2) productivity of juvenile salmon habitats, (3) production of silver eels (EDA model), The models (1)*(2) and (3) were used to predict the number of downstream migrants in the current conditions and with a transparent upstream migration. (4) Turbine mortality was calculated from either the characteristics of the turbine (diameter, rotation speed, height ...) or by extrapolation from the average mortality when information was missing to run the model. (5) Mortalities at the dam level were then derived from the nominal flow of each turbine and from the flow of the spill under 5 flow scenarios. A similar overall production of about 100 000 smolts per year was found in the Loire and Britany and the current production of eels was evaluated at 306 700, 314 900 and 124 400 silver eels for Brittany, the Loire and Vendée coastal streams respectively. The average mortality calculated at 387 dams and 578 turbines was estimated at 16.9% in Kaplan, 19.6% in Francis turbines, for smolts, and 45.8% and 88.5% for eels.
For salmon, the number of kills was evaluated as N=26 900 (ie 27% of the Loire’s smolt production), and N=1 636 (ie 2%) in Brittany. For eel, the number of kills was evaluated as N=9 800 (ie 3.1%) of the silver eel production in the Loire, N=9 400 (ie 3.3%) in Brittany and N=2 700 (ie 2.2%) in Vendée. The results will allow to prioritize actions and provide a first estimate of the level of mortality affecting eel and salmon in the Loire-Britany basin.
Session E9: Cumulated Mortalities of Salmon and Eel in the Turbines of the Loire-Brittany District
Groningen, The Netherlands
Abstract:
The effect of dams on mortality during downstream migration was simulated using distribution and mortality models in the whole Loire-Brittany water district (155 000 Km2). A combination of models was used: (1) juvenile habitats for smolts, (2) productivity of juvenile salmon habitats, (3) production of silver eels (EDA model), The models (1)*(2) and (3) were used to predict the number of downstream migrants in the current conditions and with a transparent upstream migration. (4) Turbine mortality was calculated from either the characteristics of the turbine (diameter, rotation speed, height ...) or by extrapolation from the average mortality when information was missing to run the model. (5) Mortalities at the dam level were then derived from the nominal flow of each turbine and from the flow of the spill under 5 flow scenarios. A similar overall production of about 100 000 smolts per year was found in the Loire and Britany and the current production of eels was evaluated at 306 700, 314 900 and 124 400 silver eels for Brittany, the Loire and Vendée coastal streams respectively. The average mortality calculated at 387 dams and 578 turbines was estimated at 16.9% in Kaplan, 19.6% in Francis turbines, for smolts, and 45.8% and 88.5% for eels.
For salmon, the number of kills was evaluated as N=26 900 (ie 27% of the Loire’s smolt production), and N=1 636 (ie 2%) in Brittany. For eel, the number of kills was evaluated as N=9 800 (ie 3.1%) of the silver eel production in the Loire, N=9 400 (ie 3.3%) in Brittany and N=2 700 (ie 2.2%) in Vendée. The results will allow to prioritize actions and provide a first estimate of the level of mortality affecting eel and salmon in the Loire-Britany basin.
https://scholarworks.umass.edu/fishpassage_conference/2015/June24/28
Comments
Presenting Author Bio: Cédric Briand has done his phD on glass eel population dynamic, he has worked with Russell Poole (Marine Institute, Ireland) as co-chair to the EIFAC-ICES working group on eel, and is currently works on migration monitoring and the development of eel stock assessment models. This work is the result of a long collaboration between authors from different structures, and the field work for turbine data collection was performed by ONEMA.