Assessment of silver eel (Anguilla anguilla) route selection at a water-regulating weir using an acoustic camera

2020 ◽  
Author(s):  
Eamonn S. Lenihan ◽  
T. Kieran McCarthy ◽  
Colin Lawton
Keyword(s):  
Anguilla Anguilla ◽  
Route Selection ◽  
Silver Eel

scholarly journals Just go with the flow? Route selection and mortality during downstream migration of silver eels in relation to river discharge

2007 ◽  
Vol 64 (7) ◽  
pp. 1437-1443 ◽  
Author(s):  
Henrice M. Jansen ◽  
Hendrik V. Winter ◽  
Maarten C. M. Bruijs ◽  
Harry J. G. Polman
Keyword(s):  
River Discharge ◽  
Radio Telemetry ◽  
Anguilla Anguilla ◽  
Downstream Migration ◽  
European Eel ◽  
Route Selection ◽  
Migration Routes ◽  
Silver Eel ◽  
Silver Eels ◽  
The Impact

Abstract Jansen, H. M., Winter, H. V., Bruijs, M. C. M., and Polman, H. J. G. 2007. Just go with the flow? Route selection and mortality during downstream migration of silver eels in relation to river discharge. – ICES Journal of Marine Science, 64: 1437–1443. The European eel (Anguilla anguilla) has been in steep decline for several decades. Fisheries and hydropower-induced mortality presumably play an important role during the downstream migration of silver eels, and downstream-migrating silver eels must make various navigation and route-selection decisions to reach the sea. We examined the influence of river discharge on route selection of silver eels. To quantify the impact of hydropower and fisheries on silver eel mortality, radio-telemetry experiments were performed in the River Meuse in 2002 and 2004, surgically implanting 300 silver eels with Nedap-transponders. Route selection and passage behaviour near detection stations was assessed. Silver eels were distributed over the alternative migration routes in the river in proportion to the discharge until the silver eels reached the entrance to the turbines. The eels altered their behaviour when approaching the turbines of hydropower plants and showed stationary and recurrent behaviour. We discuss the consequences of this on route selection and mortality rates caused by hydropower facilities and fisheries.

scholarly journals Yield per recruit from stocking two different sizes of eel (Anguilla anguilla) in the brackish Roskilde Fjord

2015 ◽  
Vol 73 (1) ◽  
pp. 158-164 ◽  
Author(s):  
Michael I. Pedersen ◽  
Gorm H. Rasmussen
Keyword(s):  
Growth Rate ◽  
Scientific Information ◽  
Anguilla Anguilla ◽  
Silver Eel ◽  
Glass Eel ◽  
Recovery Plan ◽  
Yellow Eel ◽  
Roskilde Fjord ◽  
Yield Per Recruit ◽  
The Eu

Abstract Stocking of young eel is widely practised, as a measure, to meet the management target of the EU eel recovery plan. The target of the recovery plan is to increase the escapement to 40% silver eel biomass, relative to pristine conditions. The scientific information to predict the outcome in silver eel biomass from stocking is limited and may depend on whether translocation of wild glass eel or yellow eel is used, or if the stocked eels used are yellow eel from aquaculture. We evaluated the yield from stocking two different sizes, 3 and 9 g eels from aquaculture. A professional fishery recaptured 12.7% of the 3 g and 9.4% of the 9 g eels, originally stocked. Growth rate and mortality rate were different for the two stocked sizes, favouring the small eels. Brutto yield per recruit (YPR) was 13 and 9.2 g and netto YPR was 9.8 and 0.31 g for 3 and 9 g eel, respectively. We conclude that there seems to be no advantage in using larger 9 g eels compared with small 3 g eels for stocking.

scholarly journals European silver eel (Anguilla anguilla L.) migration behaviour in a highly regulated shipping canal

2018 ◽  
Vol 206 ◽  
pp. 176-184 ◽  
Author(s):  
Pieterjan Verhelst ◽  
Raf Baeyens ◽  
Jan Reubens ◽  
Jean-Phillippe Benitez ◽  
Johan Coeck ◽  
...  
Keyword(s):  
Anguilla Anguilla ◽  
Silver Eel ◽  
Migration Behaviour

scholarly journals Mortality of silver eel (Anguilla anguilla) migrating downstream through a small hydroelectric plant on the Drawa River in northern Poland

2016 ◽  
Vol 24 (2) ◽  
pp. 69-75 ◽  
Author(s):  
Piotr Dębowski ◽  
Rafał Bernaś ◽  
Michał Skóra ◽  
Jacek Morzuch
Keyword(s):  
Acoustic Telemetry ◽  
Hydroelectric Plant ◽  
Anguilla Anguilla ◽  
European Eel ◽  
Upstream Migration ◽  
Silver Eel ◽  
Passive Integrated Transponder ◽  
Northern Poland ◽  
Hydroelectric Plants ◽  
Pass Through

Abstract The European eel, Anguilla anguilla L., is an endangered species. Barriers to its downstream spawning migration are one of the greatest threats this species faces. There are hundreds of hydroelectric plants (HEP) on rivers in Poland (> 600), and thousands throughout Europe. Eel that pass through HEP turbines as they migrate downstream suffer high mortality, but this depends mainly on local and technical conditions. Silver eel mortality was estimated and the possibility of the fish bypassing the turbines was studied between November 2013 and June 2014 at a typical HEP in northern Poland. Two telemetry methods were used with 49 eel: passive integrated transponder (PIT) system and acoustic telemetry. Fifty five percent of eel migrated downstream in fall 2013, soon after their release, and 45% migrated the next spring. The eel did not use the fish passes designed for upstream migration; thus, they were forced to go through the turbines, which resulted in 55% mortality. HEPs cause interruptions and delays in eel spawning migrations and are responsible for high eel mortality. This can make implementing an eel restitution plan difficult or even impossible in river systems with many barriers.

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