Abstract
The Asian shore crab (Hemigrapsus sanguineus) and the brush-clawed shore crab (H. takanoi) both originate from east Asia but have in recent years established viable populations throughout coastal European waters. The two species are highly competitive and can occur in very high densities. Both species have been linked to the decrease of otherwise abundant native species such as the European shore crab (Carcinus maenas) and the common periwinkle (Littorina littorea). As both crabs are relatively new in European coastal waters, little is known about the full distribution range that may be achieved by these crabs and the ecological impact that may follow with an invasion of coastal habitats. In this study we investigated the potential distribution of Hemigrapsus in coastal waters of Northern Europe and the potential impact on the native competitor C. maenas. To this end we collected crabs on the Swedish west coast and on Helgoland and used these for behavioural experiments. We also collected new observation records of both species in Sweden and used these occurrences for building ecological niche models. We report that the potential distribution range of both H. sanguineus and H. takanoi extends from western Sweden to eastern Ireland (east–west) and southern Norway to western France (north–south). We also found evidence that H. takanoi can establish viable populations in nutrient-rich inshore areas of the western and southern Baltic Sea and that competition by H. sanguineus is likely to affect abundances of C. maenas in the areas where these species co-occur.
Highlights
Non-indigenous species (NIS) are a global issue and the number of NIS has increased during the last decades (Cohen and Carlton 1998; European Environment Agency 2015; Zenetos et al 2012)
The behavioural experiments show that male H. sanguineus competes well with male C. maenas, even when outnumbered 2 to 5 (Fig. 1)
In areas along the American east coast, where H. sanguineus occurs together with the likewise invasive green crab (C. maenas) it has been observed that H. sanguineus outcompetes juvenile C. maenas in the competition for shelter
Summary
Non-indigenous species (NIS) are a global issue and the number of NIS has increased during the last decades (Cohen and Carlton 1998; European Environment Agency 2015; Zenetos et al 2012). European waters are especially susceptible for invasive species from Asia and North America and the main invasion vectors are ballast water and transportation across the Suez Canal (Gollasch and Nehring 2006). The Asian shore crab (Hemigrapsus sanguineus) was first discovered in Europe in 1999, found in Le Havre, France. H. sanguineus has spread along the continental coast of North western Europe, from Northern France to the German North Sea coast and has recently been found in England, Wales and Scotland (Marine Biological Association 2017; Berggren and Karlsson 2017; Dauvin 2009a; Seeley et al 2015). The species have been found in the Black Sea by the coast of Romania and in the Mediterranean Sea off the coasts of Croatia and Tunisia (Amor et al 2017; Micu et al 2010; Schubart 2003), theses were only a few or a single individual
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
