Invasion récente de la crevette asiatique Palaemon macrodactylus : cas de la Gironde (France)

Abstract

International audienceThe shrimp Palaemon macrodactylus Rathbun, 1902 is a native species of Asian waters. It was introduced into California (USA) in the 1950s and it had recently been recorded in Mar del Plata Harbor (Argentina) and in several European estuaries, such as the Guadalquivir (Spain), the Orwell (England) and the Gironde (France). In Europe, Palaemon macrodactylus was recorded belatedly after its introduction and hence very few data about its ecology and possible interactions with local shrimps are available. Since 1979, a large part of the Gironde estuary had been monthly sampled for fauna survey (mainly fish). The date of the first apparition of the oriental shrimp Palaemon macrodactylus and its expansion were inferred from the examination of the preserved samples from 1992 to 2006. The distribution of the invasive species indicated a spatial overlap with the distribution of the native species Palaemon longirostris Milne Edwards, 1837 and Crangon crangon Linnaeus, 1758, according to the seasons. We particularly focused on the possible interactions with Palaemon longirostris which supports an important traditional fisheries in the Gironde estuary (73 tonnes in the 2005). The first ecological data about P. macrodacylus in this area are presented, particularly its spatial distribution and its reproductive characters. These results revealed that the exotic species had an ecological advantage compared to the native one. P. macrodactylus is becoming an abundant element of the Palaemonid community of Gironde. The strength of the exotic population may be responsible for the decrease in abundance of the native shrimp populations