Hemigrapsus sanguineus (De Haan, 1835) (Crustacea: Brachyura: Grapsoidea) a new invasive species in European waters: the case of the French English Channel coast (2008-2010)

Jean-Claude Dauvin,Fabien Dufossé

doi:10.3391/ai.2011.6.3.09

Abstract

The unintentional introduction of the Asian shore crab, Hemigrapsus sanguineus, along the French coast during the mid 1990s has revealed the problematic effects that invasive species can have on biodiversity, entering into competition with native crab species. This invasion along coastal ecosystems of northern France has become an ineluctable, irreversible phenomenon. The present study describes the distribution and abundance of H. sanguineus along the French side of the English Channel from the Cotentin to the Opal Coast on the Dover Strait in spring and summer 2010. The results were compared with those obtained previously in 2008 and 2009 for the same areas and now show that the crab has increased in numbers since its first sighting in 1999. In 2010, the maximal abundance reached 51 ind.m -2 in Dunkirk harbour, and 69 ind.m -2 at La Hougue in the eastern part of the Cotentin Peninsula. Hemigrapsus sanguineus has been sighted all along the southern coastline of the English Channel to the North Sea (approximately 1,500 km). Its high colonisation potential suggests that this brachyuran could continue its invasion in European waters. Therefore a European surveillance network might be necessary to monitor its progression in the north-eastern Atlantic Ocean.

Highlights

The Asian crab Hemigrapus sanguineus (De Haan, 1835) has colonised most of the French English Channel coast since it was first introduced into Le Havre harbour in 1999 (Breton et al 2002; Dauvin 2009a, b; Dauvin et al 2009)
In the case of H. sanguineus, it is suspected that its introduction, as well as another Asian crab (the brush-clawed shore crab Hemigrapsus takanoi Asakura and Watanabe, 2005, could reduce the abundance of the autochthonous green crab Carcinus maenas (Linnaeus, 1758) in the areas colonized by these species (Dauvin et al 2009)
Along the Opal Coast, two main areas colonized by Hemigrapsus sanguineus could be identified: 1) the sites in the southern part of Boulogne-sur-mer, which were poorly colonised, with only one specimen collected at Berck and 11 at Le Portel in 2010, and 2) the sites from Boulogne-sur-mer to Dunkirk, which were abundantly colonised by H. sanguineus, especially the sites with high hydrodynamics exposure outside the harbours (Figure 1, Table 1)

Summary

Introduction

The Asian crab Hemigrapus sanguineus (De Haan, 1835) has colonised most of the French English Channel coast since it was first introduced into Le Havre harbour in 1999 (Breton et al 2002; Dauvin 2009a, b; Dauvin et al 2009). Introduced species may have major effects on the characteristics and dynamics of the colonised ecosystem (Occhipinti-Ambrogi 2007). These often negative effects affect the flux of matter and the trophic chains causing the mortality of some autochthonous species due to great interspecies competition. In the case of H. sanguineus, it is suspected that its introduction, as well as another Asian crab (the brush-clawed shore crab Hemigrapsus takanoi Asakura and Watanabe, 2005, could reduce the abundance of the autochthonous green crab Carcinus maenas (Linnaeus, 1758) in the areas colonized by these species (Dauvin et al 2009). In the case of H. sanguineus, its expansion rate has been estimated at 12 km per year along the eastern coast of the United States (Leppäkoski and Olenin 2000)

Objectives

Methods

Results

Conclusion