scholarly journals Relationship between locomotor activity, environmental factors, and timing of the spawning migration in the European eel,Anguilla anguilla

2008 ◽  
Vol 21 (2) ◽  
pp. 163-170 ◽  
Author(s):  
Caroline M.F. Durif ◽  
Francois Travade ◽  
Jacques Rives ◽  
Pierre Elie ◽  
Claude Gosset
Keyword(s):  
Locomotor Activity ◽  
Environmental Factors ◽  
Anguilla Anguilla ◽  
Spawning Migration ◽  
European Eel

Oceanic Spawning Migration of the European Eel (Anguilla anguilla)

Science ◽  
2009 ◽  
Vol 325 (5948) ◽  
pp. 1660-1660 ◽  
Author(s):  
K. Aarestrup ◽  
F. Okland ◽  
M. M. Hansen ◽  
D. Righton ◽  
P. Gargan ◽  
...  
Keyword(s):  
Anguilla Anguilla ◽  
Spawning Migration ◽  
European Eel

scholarly journals European eel (Anguilla anguilla): prediction of spawner escapement from continental population parameters

2000 ◽  
Vol 57 (8) ◽  
pp. 1627-1635 ◽  
Author(s):  
Eric Feunteun ◽  
Anthony Acou ◽  
Pascal Laffaille ◽  
Antoine Legault
Keyword(s):  
Population Structure ◽  
Environmental Factors ◽  
Anguilla Anguilla ◽  
Downstream Migration ◽  
The Other ◽  
European Eel ◽  
Population Parameters ◽  
Sedentary Population ◽  
Continental Population ◽  
Silver Eels

This paper describes the assessment of silver European eel (Anguilla anguilla) escapement based on a "sedentary" population fraction analysis in a 60-km2 watershed of northern Brittany (France). Downstream migration fluxes were monitored using eel traps and related to environmental factors. Intensive electrofishing and fyke-net fishing were conducted to assess eel biomass, densities, and population structure. A total of 564 eels, including 81 silver eels, were PIT tagged. In 1996, 616 eels were caught in the catchment including 68 silver eels (11%). During the following downstream migration period, 12 of the PIT-tagged silver eels, among a total of 678, were recaptured in the downstream traps. Seven were recaptured in the catchment in 1997. It was shown that (i) only about 20% of the silver eels present in the catchment emigrated during the following year, (ii) 12% stayed in the catchment including two (3.4%) that recovered yellow eel characteristics, and (iii) the other eels either died or settled in the catchment but were not recaptured. It was also estimated that 2% (650 eels) of the population (34 000 eels) among 3000 silver eels considered "emigration candidates" emigrated each year,.

European eel Anguilla anguilla compromise speed for safety in the early marine spawning migration

2018 ◽  
Vol 75 (6) ◽  
pp. 1984-1991 ◽  
Author(s):  
Robert J Lennox ◽  
Finn Økland ◽  
Hiromichi Mitamura ◽  
Steven J Cooke ◽  
Eva B Thorstad
Keyword(s):  
Anguilla Anguilla ◽  
Spawning Migration ◽  
European Eel ◽  
Population Declines ◽  
Long Distance ◽  
Directed Movement ◽  
Freshwater Habitat ◽  
Silver Eels ◽  
Marine Migration ◽  
Long Distance Movement

Abstract There are substantial benefits to potential fitness conferred to animals that undertake migrations. However, animals must make compromises to maximize survival and compensate for the risks associated with long-distance movement. European eel (Anguilla anguilla), a migratory catadromous fish, has undergone population declines owing to changes in marine and freshwater habitat and interactions with human infrastructure, instigating research to investigate the mechanisms controlling their migration. Yellow-phase European eels from the local River Opo and silver-phase European eels transplanted from River Imsa, Norway, were implanted with acoustic transmitters and released within a network of receiver stations in the Hardangerfjord, Norway. Silver-phase eels exhibited more movement within the array than yellow-phase eels, signifying the onset of migration. Silver-phase eels moved through the fjord nocturnally, arriving at gates predominantly at night. Eels had slower rates of migration than expected based on models predicting continuous movement, suggesting that movement ceased during daylight hours. Reduced net rates of travel supported the hypothesis that eels compromise speed for safety during the early marine migration by avoiding predators and not actively migrating during daylight. The silver eels were capable of directed movement towards the ocean and were not recorded by receivers in bays or dead ends. European eels must successfully transit this coastal zone, where their residence is prolonged because of the relatively slow speeds. These results suggest that the early marine phase of the European eel spawning migration be a focal period for European eel conservation efforts.

scholarly journals Empirical observations of the spawning migration of European eels: The long and dangerous road to the Sargasso Sea

2016 ◽  
Vol 2 (10) ◽  
pp. e1501694 ◽  
Author(s):  
David Righton ◽  
Håkan Westerberg ◽  
Eric Feunteun ◽  
Finn Økland ◽  
Patrick Gargan ◽  
...  
Keyword(s):  
Anguilla Anguilla ◽  
Spawning Migration ◽  
European Eel ◽  
Data Sets ◽  
Sargasso Sea ◽  
Migration Routes ◽  
Diel Vertical Migrations ◽  
Using Data ◽  
Migratory Strategy ◽  
Electronic Tagging

The spawning migration of the European eel (Anguilla anguillaL.) to the Sargasso Sea is one of the greatest animal migrations. However, the duration and route of the migration remain uncertain. Using fishery data from 20 rivers across Europe, we show that most eels begin their oceanic migration between August and December. We used electronic tagging techniques to map the oceanic migration from eels released from four regions in Europe. Of 707 eels tagged, we received 206 data sets. Many migrations ended soon after release because of predation events, but we were able to reconstruct in detail the migration routes of >80 eels. The route extended from western mainland Europe to the Azores region, more than 5000 km toward the Sargasso Sea. All eels exhibited diel vertical migrations, moving from deeper water during the day into shallower water at night. The range of migration speeds was 3 to 47 km day−1. Using data from larval surveys in the Sargasso Sea, we show that spawning likely begins in December and peaks in February. Synthesizing these results, we show that the timing of autumn escapement and the rate of migration are inconsistent with the century-long held assumption that eels spawn as a single reproductive cohort in the springtime following their escapement. Instead, we suggest that European eels adopt a mixed migratory strategy, with some individuals able to achieve a rapid migration, whereas others arrive only in time for the following spawning season. Our results have consequences for eel management.

Metazoan Parasites and Health State of European Eel, Anguilla Anguilla (Anguilliformes, Anguillidae), From Tonga Lake and El Mellah Lagoon in the Northeast of Algeria

2018 ◽  
Vol 52 (4) ◽  
pp. 279-288 ◽  
Author(s):  
F. Bakaria ◽  
S. Belhaoues ◽  
N. Djebbari ◽  
M. Tahri ◽  
I. Ladjama ◽  
...  
Keyword(s):  
Brackish Water ◽  
Parasite Species ◽  
Anguilla Anguilla ◽  
European Eel ◽  
Health State ◽  
Component Community ◽  
Metazoan Parasites ◽  
Parasite Communities ◽  
High Dominance ◽  
Argulus Foliaceus

Abstract The aim of the study was to examine metazoans parasite communities of European eels (Anguilla anguilla) in freshwater (Tonga Lake) and brackish water (El Mellah lagoon) in the northeast of Algeria. Six parasite taxa were collected: one monogenean, Pseudodactylogyrus sp.; two crustaceans, Ergasilus sp. and Argulus foliaceus; two nematodes, Cucullanus sp. and Anguillicola crassus; one cestode, Bothriocephalus claviceps. Th e most prevalent parasite taxa in freshwater were Pseudodactylogyrus sp., A. crassus and Bothriocephalus claviceps; whereas in the brackish water, eels were infected mainly with A. crassus. Th e characteristics of the parasite component community structure revealed low parasite species diversity and high dominance values in eels from the two localities. Both communities were dominated by a single parasite species: Tonga eels by the monogenean Pseudodactylogyrus sp. and El Mellah lagoon eels by the nematode A. crassus, verified by high Berger-Parker dominance values of 0.76 and 0.87 respectively.

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