Bibliography of the Maurice Lamontagne Institute

Brigitte LÉVESQUE

LAMBERT, P., G. VERREAULT, B. LÉVESQUE, V. TREMBLAY, J.-D. DUTIL, P. DUMONT, 2011. Détermination de l'impact des barrages sur l'accès de l'anguille d'Amérique (Anguilla rostrata) aux habitats d'eau douce et établissement de priorités pour des gains en habitat. Rapp. Tech. Can. Sci. Halieut. Aquat., 2921, 53 p .

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American eel (Anguilla rostrata) experience a marked decline in the St. Lawrence River. Access to freshwater is impaired by an ever growing number of dams some of which are used for hydropower and cause mortalities to downstream migrants. A model is proposed to prioritize mitigation schemes in the Rimouski River (Quebec), a 1376 km long mid-size watershed on which 23 barriers higher than 1 m occur. A diffusion rate of 20 km² year-1 over a 20 year period was applied in the model. The impact of each barrier was simulated by reducing movements upstream at the barrier, survival among eels blocked downstream, and survival of eels at the barrier during the downstream migration. Model outputs have stressed the prime importance of a single dam located near the estuary in determining the colonization process whereas mitigating other dams in the watershed did not significantly improve spawning escapement. Setting priorities among watersheds poses additional challenges. There are differences in growth, fecundity and size at maturity among watersheds and these have an effect on egg production associated with spawning escapement. Size at maturity within a watershed was found to correlate with the observed back-calculated growth rate of eel from age 1 to age 10 in the watershed. OMMER (Obstacle Mitigation Model for Eel in Rivers) is a valuable tool to compare a range of management scenarios aimed at mitigating upstream and downstream passage at barriers, though its extension to other watersheds is currently limited by the availability of relevant data for a diversified set of habitats and watersheds.