First record of Chelicorophium curvispinum (G.O. Sars, 1895) from Lake Mälaren, SE Sweden

The Ponto-Caspian amphipod Chelicorophium curvispinum (G.O. Sars, 1895) was first recorded in the Baltic Sea catchment area in the early 20 century. Since then the species has considerably extended its distribution. Here, we present the first record of the invasive amphipod in Sweden (Drottingholm, Lake Mälaren, SE Sweden). It is plausible that C. curvispinum was initially introduced via shipping to the brackish waters of the Stockholm Archipelago. National ferry traffic may have provided a subsequent means of transport for this species from Stockholm centrum to Lake Mälaren.