Who’s next? Marinas of the Red Sea, potential sources of marine species introductions in the Mediterranean Sea

The arrival of Indo-Pacific species in the Mediterranean Sea is a process not yet fully understood. Species may have been introduced by two distinct vectors: spontaneous migration through the Suez Canal, or hitch-hiking on ships that navigate through the Canal. When a new Indo-Pacific species appears in the Mediterranean, its vector of introduction is often only a guess. In this work we analyse fouling communities in marinas and moorings along the Egyptian coast of the Red Sea, in order to unveil the possible source and vector of alien species already entered in the Mediterranean Sea and identify potential new invaders. Within a CICOPS fellowship (University of Pavia), a collaboration project between the Department of Earth and Environmental Sciences (University of Pavia, Italy) and the National Institute of Oceanography and Fisheries (Egypt) was carried out. Two different survey methods were carried out in different localities along the northern Red Sea coast (from Qusier to Hurghada), in summer 2017. Samples were collected both from PVC panels and concrete docks, or other artificial substrates. We found over 20 species, including bryozoans, crustaceans, molluscs and polychaetes, that are considered alien species in the Mediterranean; thus supporting the hypothesis that they might have been introduced by boats travelling from there. The fouling communities observed were also composed by some Indo-Pacific species that had never been reported before from the Red Sea. These results raises a new question: is the Red Sea part of their natural geographic range, or have they been brought there artificially by boats? Finally, few taxonomically unresolved specimens were found, probably undescribed species. For a better knowledge of fouling communities of the Red Sea and the on-going alteration of the biogeography of marine biota caused by human activities, scientific cooperation among countries should be promoted.