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:
A trial was conducted with passage ways for migrating silver eel at a low head weir in a tributary to River Mörrumsån in Sweden. Behavioral traits useful for maximizing the number of eel per volume of water were sought. Six openings were made in the weir and supplied with various set-ups. One of the openings, a plain hole, served as a control. A second opening had significantly more eel passing than the control (11 versus 2; p<0.05). This setup (U-chute) had a raceway extending 7m upstream of the weir. Inflow of water (and eel) took place through vertical slots on the side. Further development of this model is advocated. Two other set-ups had about the same number of eel passing (4 and 2) as the control. The first was a nature like bypass. The other, the M-chute, had a submerged raceway extending 7m upstream. Inflow took place over the sides. The last two set-ups had no eel passing through or entering, and very few eel were observed near. The first was a dead end (no water flow) and the second had a flow of water coming out of the entrance. A separate trial, involving silver eel and modified water quality, was carried out at the aquarium experimental facility at Ar, Sweden. Eel, kept in 4m² experimental fresh water fish tanks, were offered two narrow escape ways. One opening had an inflow of brackish water, the other opening had an inflow of fresh water. Significantly more eel passed out through the opening with brackish water than the opening with fresh water (21 versus 8; p<0.05). This effect was however not deemed strong enough for attracting eel to passages. It is argued there is a need for better knowledge of silver eel migration behavior during the descent to the sea.
Session C5: Experiments to Improve Passage Ways for Downstream Migrating Silver Eel
Groningen, The Netherlands
Abstract:
A trial was conducted with passage ways for migrating silver eel at a low head weir in a tributary to River Mörrumsån in Sweden. Behavioral traits useful for maximizing the number of eel per volume of water were sought. Six openings were made in the weir and supplied with various set-ups. One of the openings, a plain hole, served as a control. A second opening had significantly more eel passing than the control (11 versus 2; p<0.05). This setup (U-chute) had a raceway extending 7m upstream of the weir. Inflow of water (and eel) took place through vertical slots on the side. Further development of this model is advocated. Two other set-ups had about the same number of eel passing (4 and 2) as the control. The first was a nature like bypass. The other, the M-chute, had a submerged raceway extending 7m upstream. Inflow took place over the sides. The last two set-ups had no eel passing through or entering, and very few eel were observed near. The first was a dead end (no water flow) and the second had a flow of water coming out of the entrance. A separate trial, involving silver eel and modified water quality, was carried out at the aquarium experimental facility at Ar, Sweden. Eel, kept in 4m² experimental fresh water fish tanks, were offered two narrow escape ways. One opening had an inflow of brackish water, the other opening had an inflow of fresh water. Significantly more eel passed out through the opening with brackish water than the opening with fresh water (21 versus 8; p<0.05). This effect was however not deemed strong enough for attracting eel to passages. It is argued there is a need for better knowledge of silver eel migration behavior during the descent to the sea.
https://scholarworks.umass.edu/fishpassage_conference/2015/June23/22
Comments
Presenting Author Bio: First Author: Focus on development of new methods and techniques for fisheries research and management. Second author: Focus on implementation of the Swedish Eel Management Plan. Third author: Focus on co-ordination of Swedish eel research.