Attachment ability of two invasive amphipod species may promote their spread by overland transport

Amphipods are very successful invaders in European inland waters including lakes. There are several vectors identified as responsible for amphipod species introductions and spread, with overland transport increasingly recognized as particularly important, especially in conjunction with transport between sites of sailing and/or angling activity. In this study two species of invasive gammarids with a wide distribution range in Europe, Dikerogammarus haemobaphes and Pontogammarus robustoides , were tested for their ability to attach and remain adhered to sailing rope. The results of the experiment show that both species may have high potential to be transported with sailing/angling equipment, as the percentage of individuals remaining attached to the rope after 30 s of ‘holding’ followed by 30 s of ‘shaking’ was very high (24% and 17%, for D . haemobaphes and P . robustoides , respectively). The necessity for preventative measures to stop translocation of these species between European water bodies is emphasized and discussed.