Assessment of eel stock status in Garonne and Dordogne water bodies by analysing length structures ...

• Main Authors: Lambert, Patrick, Beaulaton, Laurent, Daverat, Françoise, Rigaud, Christian
• Format: Conference Object
• Language: unknown
• Published: ASC 2006 - Theme session J 2024
• Subjects: Fisheries and aquaculture; Ecosystem observation, processes and dynamics; Anguilla anguilla
• Online Access: https://dx.doi.org/10.17895/ices.pub.25258900; https://ices-library.figshare.com/articles/conference_contribution/Assessment_of_eel_stock_status_in_Garonne_and_Dordogne_water_bodies_by_analysing_length_structures/25258900

No abstracts are to be cited without prior reference to the author.We analysed length structure of European eel (Anguilla anguilla) stocks with a simple size-structured model including a linear trend of recruitment, a linear growth curve, a negative exponential mortality and a silvering process based on a gamma function. Eels shorter than 30 cm were excluded from the analysis in order to limit effect of sex determinism, colonization process and gear selectivity. The data sets used in this study were obtained from Water Framework Directive (WFD) survey and sampling that can be assimilated to Data Collection Regulation (DCR) survey in the Garonne and Dordogne basin covering seven “WFD water bodies” (from downstream estuary to upstream tributaries). Even if the calibration remained very sensitive to parameter boundaries, this approach allowed calculation of percentages of silver eels per settled yellow eels in each water bodies. The resulting percentages obtained for each water body matched our knowledge of the ...