The Influence of Light and Other Factors on the Seaward Migration of the Silver Eel (Anguilla anguilla L.)

10.2307/1963 ◽  
1952 ◽  
Vol 21 (2) ◽  
pp. 275 ◽  
Author(s):  
Rosemary H. Lowe
Keyword(s):  
Anguilla Anguilla ◽  
Silver Eel ◽  
Seaward Migration

Environmental Factors Regulating the Seaward Migration of European Silver Eels (Anguilla anguilla)

1986 ◽  
Vol 43 (10) ◽  
pp. 1909-1916 ◽  
Author(s):  
L. A. Vøllestad ◽  
B. Jonsson ◽  
N. A. Hvidsten ◽  
T. F. Næsje ◽  
Ø. Haraldstad ◽  
...  
Keyword(s):  
Water Temperature ◽  
Total Variation ◽  
Opposite Effect ◽  
Field Experiments ◽  
Water Discharge ◽  
Anguilla Anguilla ◽  
Silver Eel ◽  
Discharge Water ◽  
Silver Eels ◽  
Seaward Migration

We examined the connection between descent of European silver eels (Anguilla anguilla) and water discharge, water temperature, turbidity, photoperiod, light intensity, and moon phase based on 10 yr of field data and field experiments. The eel migration takes place between August and December, and mean water temperature for July–August and mean water discharge for August–October explained 91% of the total variation in the start of the yearly silver eel run. Low mean water temperatures during July–August and high mean water discharge during August–October resulted in an early start of the yearly silver eel run, whereas high mean water temperature and low water discharge gave the opposite effect. There was no significant correlation between the duration of the entire yearly silver eel run and the environmental variables investigated. But the duration of a part of the run, e.g. number of days from 5 to 25% cumulative eel descent, was significantly correlated with mean water temperature and increase in water discharge for the period in question (R2 = 0.84). Maximum silver eel descent was at a water temperature of 9 °C. Few silver eels descended at temperatures below 4 °C or above 18 °C. The migration speed of transplanted silver eels in the River Imsa was correlated with water discharge and water temperature (R2 = 0.88). Water discharge alone explained 85% of the total variation in migration speeds. The recapture rate of silver eels transplanted within the River Imsa was highest at 9 °C and decreased at higher and lower temperatures (R2 = 0.95). Illumination of 20 lx upon the river reduced the descent of silver eels.

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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