Male brush-clawed shore crabs have a patch of light brown or yellow bristles (known as setae) on their chelae (pincers).

The ship was known to have passed the French coast in 1993, and it is thought that the introduction is likely to have occurred when crabs fell from the hull of the SPICA at that time.

[5] By 1997, its range in Europe extended from Fromentine in France (adjacent to the Île de Noirmoutier) to Laredo, Spain, covering a coastline of 700 kilometres (430 mi) around the Bay of Biscay.

[12] The first record in the Baltic region was in 2014 when individuals were caught in the Kiel Fjord in Germany, likely having arrived via the many ships that pass through the Kiel Canal (which connects the North Sea and Baltic Sea region),[8] and in 2018 it was first recorded in Denmark's South Funen Archipelago.

[10] In 2023, two adult males were recorded in Poland in Gdańsk Bay, but establishment in the Baltic Proper might be limited by low salinity impairing larval development.