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

Posters of the International Eel Symposium


A number of posters were submitted as part of the symposium. They covered a broad range of topics, as indicated by the titles and abstracts provided here. The authors were introduced, and the senior authors provided a two-minute rapid overview during the presentation. This presentation was in addition to being part of the usual American Fisheries Society poster session.

A sub-population of European eels (Anguilla anguilla) was sampled along the length of a small coastal catchment during summer for seven consecutive years to determine spatiotemporal variations of population characteristics. Two hypothesis were explored: firstly, do habitat preferences vary among sizes and sex; secondly, are habitat preferences and spatial organization patterns influenced by population parameters (density, size structure, and sex ratio). Thus years, spatial distribution, and habitat characteristics were simultaneously explored using a GLM approach. For each of the four selected length classes (<150, [151–300], [301–450] and >451 mm), variations of abundance were better explained by spatial (distance to the sea and to a dam) and temporal (yearly variations of downstream migration) factors than habitat. Variation in eel size distribution between years was minimal for elvers and yellow eels even though high recruitment variability has been observed since 1996. This suggests that young recruits (i) delayed their upstream migration, and/or (ii) settled in deeper habitats, and/or (iii) had low survival during their migrating stages. Variability of the spatiotemporal distribution patterns was then discussed regarding the development of the river and the saturation of the habitats, suggesting that carrying capacity was reached in the whole river system.