Silver eel population size and escapement in a Mediterranean lagoon: Bages-Sigean, France

Abstract

Much concern has been raised about the decline in the European eel (Anguilla anguilla) population. European management plans for the recovery of the stock are now in preparation, the main objective being to increase the escapement of the potential spawners (silver eels) in each basin to allow 40% of the pristine biomass to escape. However, there are relatively few studies on silver eel escapement and production, and no recent measurement of escapement in lagoons, habitats which support large silver eel sub-populations in the Mediterranean region. A mark-recapture study was carried out in autumn 2007 in order to estimate the number of silver eels migrating from the Bages-Sigean lagoon in the South-West of France. The migrating population, mostly males between 36 and 42 cm, was estimated to be around 1 120 000 eels (30 kg·ha–1). The exploitation rate by professional fishermen was around 20% (6 kg·ha–1), leading to an escapement level of 80% (24 kg·ha–1). The results are discussed regarding the available data in the literature on silver eel escapement.

Keywords

• Anguilla anguilla
• silver eel
• Mediterranean lagoon
• mark-recapture
• escapement