scholarly journals Behavioural responses of European silver eels(Anguilla anguilla) to the geomagnetic field

1985 ◽  
Vol 39 (1) ◽  
pp. 71-81 ◽  
Author(s):  
L. Karlsson
Keyword(s):  
Geomagnetic Field ◽  
Anguilla Anguilla ◽  
Behavioural Responses ◽  
Silver Eels

scholarly journals Growth potential can affect timing of maturity in a long-lived semelparous fish

2018 ◽  
Vol 14 (7) ◽  
pp. 20180269 ◽  
Author(s):  
Kazuki Yokouchi ◽  
Françoise Daverat ◽  
Michael J. Miller ◽  
Nobuto Fukuda ◽  
Ryusuke Sudo ◽  
...  
Keyword(s):  
Anguilla Anguilla ◽  
Growth Conditions ◽  
Growth Potential ◽  
Individual Growth ◽  
Growth Trajectories ◽  
Female Size ◽  
European Eel ◽  
Growth And Survival ◽  
Silver Eels ◽  
Reproduction Cost

Many diadromous fishes such as salmon and eels that move between freshwater and the ocean have evolved semelparous reproductive strategies, but both groups display considerable plasticity in characteristics. Factors such as population density and growth, predation risk or reproduction cost have been found to influence timing of maturation. We investigated the relationship between female size at maturity and individual growth trajectories of the long-lived semelparous European eel, Anguilla anguilla . A Bayesian model was applied to 338 individual growth trajectories of maturing migration-stage female silver eels from France, Ireland, the Netherlands and Hungary. The results clearly showed that when growth rates declined, the onset of maturation was triggered, and the eels left their growth habitats and migrated to the spawning area. Therefore, female eels tended to attain larger body size when the growth conditions were good enough to risk spending extra time in their growth habitats. This flexible maturation strategy is likely related to the ability to use diverse habitats with widely ranging growth and survival potentials in the catadromous life-history across its wide species range.

Descent of European silver eels, Anguilla anguilla L., in a Norwegian watercourse

1985 ◽  
Vol 26 (1) ◽  
pp. 37-41 ◽  
Author(s):  
O. Haraldstad ◽  
L. A. Vollestad ◽  
B. Jonsson
Keyword(s):  
Anguilla Anguilla ◽  
Silver Eels

Eels at the Edge: Science, Status, and Conservation Concerns

2009 ◽  
Keyword(s):  
Warning System ◽  
Anguilla Anguilla ◽  
Hydropower Station ◽  
European Eel ◽  
Mortality Factors ◽  
River Meuse ◽  
Silver Eels ◽  
Hydropower Stations ◽  
Integrated Study ◽  
Migration Event

<em>Abstract.—</em>To evaluate mortality factors and potential mitigative measures during downstream passage of silver European eel Anguilla anguilla in the River Meuse, an integrated study was performed consisting of: 1) telemetric experiments where the descent of 150 transpondered eels was tracked at 14 detection stations; 2) monitoring daily commercial catches; 3) testing a system to predict migration events from activity of captive eels in riverside tanks (the Migromat system); and 4) measuring turbine mortality by netting eels at turbine outlets. Migromat systems installed at two hydropower stations predicted 41 migration events. Most warnings (58.5%) were false positives, but Migromat failed to predict only one migration event. Mortality of eels passing through a turbine at the Linne Hydropower station was 24%. However, part of the downstream migrating population bypassed the turbines by descending over adjacent weirs. Descending eels moved primarily in brief pulses that were associated with increasing discharge and especially during the first half of the night. Thirty-seven percent of transpondered eels released at Ohé en Laak reached the sea. Because both fisheries mortality (estimated at 22–26% by fishing recoveries) and hydropower mortality (estimated at 16–26%) were considerable, a reduction in fisheries harvest and implementation of turbine management by application of the Migromat warning system would substantially increase escapement of silver eels from the River Meuse.

scholarly journals Escapement of silver-phase European eels, Anguilla anguilla, determined from fishing activities in a Mediterranean lagoon (Or, France)

2011 ◽  
Vol 69 (1) ◽  
pp. 30-33 ◽  
Author(s):  
Fabien Charrier ◽  
Virgile Mazel ◽  
Jean-Marie Caraguel ◽  
Yann Abdallah ◽  
L. Laëtitia Le Gurun ◽  
...  
Keyword(s):  
Anguilla Anguilla ◽  
Marine Science ◽  
Commercial Fishery ◽  
Mediterranean Lagoon ◽  
Silver Eels ◽  
Reading Study

Abstract Charrier, F., Mazel, V., Caraguel, J-M., Abdallah, Y., Le Gurun, L. L., Legault, A., and Laffaille, P. 2012. Escapement of silver-phase European eels, Anguilla anguilla, determined from fishing activities in a Mediterranean lagoon (Or, France). – ICES Journal of Marine Science, 69: 30–33. Escapement of silver eels from a Mediterranean lagoon was estimated by a capture–tagging–recapture and automated tag-reading study. The population of silver-phase eels in the lagoon was estimated to be 13.2 kg ha−1, with an escapement rate from the commercial fishery of 76.8%.

On the application of models of European eel (Anguilla anguilla) production and escapement to the development of Eel Management Plans: the River Severn

2007 ◽  
Vol 64 (7) ◽  
pp. 1472-1482 ◽  
Author(s):  
M. W. Aprahamian ◽  
A. M. Walker ◽  
B. Williams ◽  
A. Bark ◽  
B. Knights
Keyword(s):  
Reference Conditions ◽  
Anguilla Anguilla ◽  
European Eel ◽  
Silver Eel ◽  
Management Scenarios ◽  
Test Management ◽  
Management Measures ◽  
Silver Eels ◽  
Management Plans ◽  
The Uk

Abstract Aprahamian, M. W., Walker, A. M., Williams, B., Bark, A., and Knights, B. 2007. On the application of models of European eel (Anguilla anguilla) production and escapement to the development of Eel Management Plans: the River Severn. – ICES Journal of Marine Science, 64: 1472–1482. The European eel stock has declined significantly since the 1980s, and the Eel Recovery Plan of the European Commission requires Member States to develop river basin Eel Management Plans (EMPs) that will achieve an escapement of silver eels that equals or exceeds 40% of the escapement biomass that would be produced in the absence of human activities. However, because silver eel escapement is not quantified within the UK, a modelling approach is required to estimate potential and actual escapement, and to assess the likely effects of management measures. We focus on two approaches developed in the UK, the Reference Condition Model (RCM) and the Scenario-based Model for Eel Populations (SMEP), and illustrate how such approaches can be used in EMPs using selected data from the River Severn. The RCM results indicate that the yellow eel population in the River Severn basin may be just 30–40% of the potential density indicated by reference conditions derived from a selection of rivers between the late 1970s and the early 1980s. The challenges of applying a model designed to be as realistic of eel production as possible, and the limited data on natural eel habitat and eel production in the Severn, preclude a SMEP analysis similar to that of the RCM, but simulations based on a simplified basin description and eel survey data from the early 1980s illustrate the potential of this model to assess compliance and test management scenarios.

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