Un Outil D’aide Á La Gestion De L’anguille : Le Tableau De Bord Anguillle Du Bassin Loire

Baisez, Aurore; Laffaille, Pascal

doi:10.1051/kmae:2005007

Cited by 17 publications

(27 citation statements)

References 35 publications

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“…Indeed, as we have so little information about the marine phase and are unable to control oceanographic conditions, the best we can do is to optimize the production of spawners (in terms of biomass and quality) in continental areas. In this context, Feunteun (2002) and Baisez and Laffaille (2005) suggest that the best scale of investigation is that of the catchment area. As a first step and for management purposes, we need indicators to monitor the continental stages.…”

Section: > Defining the Problem And The Objectivesmentioning

confidence: 99%

“…Such indicators could be combined in a local eel report card. An eel report card seems to be the best way of measuring the impact of the management actions, and providing advice about how to maintain or improve the eel population, taking into account the mortality of the species on the catchment scale (Baisez and Laffaille, 2005). Yellow eel stock assessments and surveys are common, but they have been based on different sampling methods (Naismith and Knights, 1990;Knights et al, 1996;Jellyman and Graynoth, 2005;Laffaille et al, 2005a).…”

Section: > Defining the Problem And The Objectivesmentioning

confidence: 99%

“…When they reach a threshold size, they metamorphose into the silver eels that migrate to the Sargasso Sea spawning area where they reproduce just once. Managers need to be able to monitor the freshwater population distribution and assess its current status (Feunteun, 2002;Baisez and Laffaille, 2005). However, such a complex life cycle makes this difficult.…”

Section: Introductionmentioning

confidence: 99%

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Assessing the freshwater distribution of yellow eel

Lasne

Laffaille

2008

Knowl. Managt. Aquatic Ecosyst.

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In the global context of the decline in wild species, modeling the distribution of populations is a crucial aspect of ecological management. This can be a major challenge, especially for species, such as the European eel, that have complex life cycles, exhibit cryptic behavior, or migrate over long distances. A review of the literature suggests that eel size data could be used to assess and analyze freshwater distribution of eel. We argue that analyses based on small yellow eels (≤ 300 mm) along the longitudinal course of rivers could provide a valuable tool for population monitoring. We propose a standardized catchment recruitment index and a colonization index based on the probability of occurrence (presence/absence data) using logistic models for different size classes. The model developed here provides a convenient guide for assessing yellow eel stages in freshwater areas, and should have concrete applications for management of the species. RÉSUMÉ Évaluation de la distribution des anguilles jaunes en eau douceDans le contexte actuel de déclin des espèces, la modélisation de la distribution des populations est une étape importante pour la gestion de la biodiversité. Cependant, cette modélisation peut s'avérer difficile, particulièrement pour les espèces qui, comme l'anguille européenne, possèdent des cycles de vie complexes, ont un mode de vie cryptique ou effectuent de grandes migrations. Un examen de la littérature suggère que la taille des anguilles peut être utilisée comme critère pour évaluer et analyser la distribution des anguille en eau douce. Nous suggérons que l'examen des patrons de distribution des petites anguilles (≤ 300 mm) le long des réseaux hydrographiques peut fournir des informations précieuses pour le suivi des populations. Nous proposons un indice standardisé de recrutement et de colonisation des bassins versants sur la

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Section: > Defining the Problem And The Objectivesmentioning

confidence: 99%

Section: > Defining the Problem And The Objectivesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Assessing the freshwater distribution of yellow eel

Lasne

Laffaille

2008

Knowl. Managt. Aquatic Ecosyst.

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“…The European eel is an important resource in terms of conservation, ecology and socioeconomic considerations (Baisez and Laffaille, 2005). All continental stages (from the glass eel to the silver eel) are harvested with a mean annual global production of around 20 000 metric tons of eel, corresponding to 2 billion individual eels caught per year for the whole of Europe (Dekker, 2000).…”

Section: Introductionmentioning

confidence: 99%

“…It is now apparent that effective networks are essential to monitor changes in the situation of this species in order to assess the impact of the management strategies implemented, and to make it possible to preserve fishing rights and sustainable fisheries in the long term. An eel report card seemed to be the best way to measure the impact of the management measures, and to provide advice about the eel population situation, taking into account the mortality of the species on the scale of the catchment area (Baisez and Laffaille, 2005). With regard to the continental yellow eel stage in the Loire, the eel distribution could be obtained from the sampling network of the ONEMA (the French National Office for Water and the Aquatic Environment), which covers 135 sites around the Loire catchment basin.…”

Section: Introductionmentioning

confidence: 99%

Strategy of recreational anglers and estimated eel (Anguilla anguilla) catches in a large European catchment basin, the Loire (France)

Baisez

Laffaille

2008

Knowl. Managt. Aquatic Ecosyst.

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The European Council Regulation (18 September 2007) for the recovery of eel stocks required European states to report on eel stocks and anthropic mortalities. The data sources for France reveal gaps in our knowledge about angling in the public domain, and catches from privately-owned rivers. We tested a simple method, using a survey, for estimating the strategy employed and the catches landed by the 350 000 anglers fishing in the Loire catchment area. The first findings show that the answers of the fishermen varied between 1 and 2% in the departments with the most eels, and between 0.1 and 0.2% in the departments located further upstream. The interest in eel fishing, the average weight of the eels caught by the fishermen, and the total catch all decreased from downstream to upstream. Finally, we estimated the annual average weight of eel caught by anglers, which ranged from 0.8 to 5.3 kg per year depending on the department and the local interest in eel fishing. This preliminary study shows that it is possible to estimate the different fishing strategies used and the quantities caught by means of a survey. RÉSUMÉ

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Prioritization of fish assemblages with a view to conservation and restoration on a large scale European basin, the Loire (France)

et al. 2008

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The hierarchical organization of important sites for the conservation or the restoration of fish communities is a great challenge for managers, especially because of financial or time constraints. In this perspective, we developed a methodology, which is easy to implement in different locations. Based on the fish assemblage characteristics of the Loire basin (France), we created a synthetic conservation value index including the rarity, the conservation status and the species origin. The relationship between this new synthetic index and the Fish-Based Index allowed us to establish a classification protocol of the sites along the Loire including fish assemblages to be restored or conserved. Sites presenting disturbed fish assemblages, a low rarity index, few threatened species, and a high proportion of non-native species were considered as important for the restoration of fish biodiversity. These sites were found mainly in areas where the assemblages are typical of the bream zone, e.g. with a higher number of eurytopic and limnophilic species. On the contrary, important sites for conservation were defined as having an important conservation potential (high RI, a lot of threatened species, and few nonnatives fish species) and an undisturbed fish assemblage similar to the expected community if habitats are undisturbed. Important sites for conservation were found in the Loire basin's medium reaches which host assemblages typical for the grayling and the barbell zones, e.g. with a higher number of rheophilic species. The synthetic B. Bergerot (&) Á E. Lasne Á P. Laffaille ERT 52-Bâtiment 25 'biodiversité fonctionnelle et gestion des territoires', University of Rennes 1, 1er étage, conservation value index could be adapted and completed with other criteria according to management priorities and capacities.

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Un Outil D’aide Á La Gestion De L’anguille : Le Tableau De Bord Anguillle Du Bassin Loire

Cited by 17 publications

References 35 publications

Assessing the freshwater distribution of yellow eel

Assessing the freshwater distribution of yellow eel

Strategy of recreational anglers and estimated eel (Anguilla anguilla) catches in a large European catchment basin, the Loire (France)

Prioritization of fish assemblages with a view to conservation and restoration on a large scale European basin, the Loire (France)

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