The Chinese mitten crab Eriocheir sinensis H. Milne Edwards, 1853 is a native crab of East Asia. It is predominant in freshwater but migrates seawards to breed. It was found in Normandy, for the first time, in 1943 (Hoestlandt, 1943, 1948). Seventy-one years of observations along the Normandy coast and in the Seine estuary, as well as in the ship-canals and inner seaport of Le Havre, have recorded a total of 65 crabs at 33 locations. The observation of an E. sinensis juvenile in mussel beds along the Calvados coast indicates that this habitat can be a favourable location for larval settlement.
