Presence of Palaemon macrodactylus in a European estuary: evidence for a successful invasion of the Gironde (SW France)

Mélanie Béguer,Philippe Philippe Boët,Julien Bergé,Joanna Martinet,Gaëlle Pauliac,Michel Girardin,Jean Martin

doi:10.3391/ai.2011.6.3.07

Abstract

Palaemon macrodactylus, an exotic shrimp native to the northwest Pacific Ocean, has been recorded in many estuaries along the Atlantic coast of Europe since the late 1990’s. In this study, a regular monthly survey, held since 1992 of the middle section of the Gironde estuary, revealed this species’ rapid and full colonization of the system since its appearance in samples during summer 1998. In the Gironde, the population of P. macrodactylus is self-sustaining and the species is now established there. Our study highlights two important elements that might explain its successful colonization: its ability to quickly invade a niche under-exploited by the similar native species and its greater reproductive output. The species’spatio-temporal distribution in relation to environmental variables was studied and compared with that of the native species P. longirostris. The exotic species was shown to mainly inhabit the polyhaline and mesohaline section of the estuary, which are sections generally under-exploited by females of the native species. Furthermore, fecundity analysis and larval abundance survey results revealed a higher potential fecundity and a greater proportion of larvae and juvenile stages for P. macrodactylus in the natural environment.

Highlights

Estuaries are among the most exposed systems to biological invasions; about one species in five would be non-native in European estuaries (e.g. Gollasch 2006; Reise et al 2006; Ruiz et al 1997; Ruiz et al 1999)
Our study provides strong evidence that Palaemon macrodactylus has become established in the Gironde estuary since its first appearance in our samples in summer 1998
The oldest samples that were reexamined (1992-1997) did not identify the presence of any exotic shrimp. This seems to be the oldest record of this species in European waters, in addition to the Guadalquivir one (González-Ortegón et al 2009)

Summary

Introduction

Estuaries are among the most exposed systems to biological invasions; about one species in five would be non-native in European estuaries (e.g. Gollasch 2006; Reise et al 2006; Ruiz et al 1997; Ruiz et al 1999). The population biology of invasive species, their life history traits and ecology, should be better known to understand mechanisms and characteristics involved in the successful process of invasion (Crawley 1987; Sakai et al 2001). The increase in these type of studies would allow us to predict the invasibility of systems and pinpoint which species are the most predisposed to invade such type of system (Sakai et al 2001). Invasive species can interact directly (e.g predation, competition, parasitism) or indirectly (e.g. habitat disturbances, cascading trophic interactions) with the natives species (Sakai et al 2001)

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