Analysis of potential distribution and impacts for two species of alien crabs in Northern Europe

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 nutrientrich 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.

Exploring larval phenology as predictor for range expansion in an invasive species

“…Northward larval transport to the Norwegian coast will be favoured by coastal currents (Winther and Johannessen ), but currents flowing southwards in the eastern British side of the North Sea may limit northward transport in Great Britain (but see Karlsson et al ). The fact that H. sanguineus is already present in the S Scandinavian coast (Sweden: Karlsson et al ), speaks against restrictions in range distribution for that region either in the larval or adult habitats. On the shores of N Europe, the only intertidal competitor is the predatory crab Carcinus maenas , but that species already coexists with H. sanguineus in North America and N Europe (Lohrer and Whitlatch , Jungblut et al ).…”

“…Range distributions may be driven by effects of current flow on larval transport (Gaylord and Gaines 2000). Northward larval transport to the Norwegian coast will be favoured by coastal currents (Winther and Johannessen 2006), but currents flowing southwards in the eastern British side of the North Sea may limit northward transport in Great Britain (but see Karlsson et al 2019). The fact that H. sanguineus is already present in the S Scandinavian coast (Sweden: Karlsson et al 2019), speaks against restrictions in range distribution for that region either in the larval or adult habitats.…”

Prey preferences of invasive (Hemigrapsus sanguineus, H. takanoi) and native (Carcinus maenas) intertidal crabs in the European Wadden Sea

“…Since the first records in France and the southern Netherlands, both species have spread rapidly and their current distribution reaches along the continental European coast from France to the Baltic Sea. More recently, individuals of both species have also been reported from Great Britain (Epifanio, 2013;Seeley et al, 2015;Wood et al, 2015;Karlsson et al, 2019).…”

“…In invaded ecosystems the two Hemigrapsus species can commonly be found in sympatry with the native European shore crab Carcinus maenas (Linnaeus 1758) (Breton et al, 2002;Dauvin et al, 2009;Karlsson et al, 2019). Where they occur together, the invasive Hemigrapsus spp.…”

Ontogeny of osmoregulation of the Asian shore crab Hemigrapsus sanguineus at an invaded site of Europe

“…In North America, H. sanguineus was first recorded in the 1980s, in the Delaware Bay and it subsequently expanded northwards over 10 degrees of latitude ( Epifanio et al ., 1998 ; Stephenson et al ., 2009 ; Epifanio, 2013 ; Lord and Williams, 2017 ). In Europe, H. sanguineus was first found in the Dutch delta system in 1999 ( Dauvin et al ., 2009 ) and then it expanded over the North Sea ( Jungblut et al ., 2017 ; Geburzi et al ., 2018 ; Jungblut et al ., 2018 ), reaching also the coast of Scandinavia ( Karlsson et al ., 2019 ). In the German Bight (North Sea), H. sanguineus has invaded the intertidal zones of the Wadden Sea where densities average reached values of the order of 500 crabs m −2 ( Geburzi et al ., 2018 ; Fig 3 , C6: size range ≤ 10 mm).…”