Red Sea marinas as potential source of marine alien species

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: active movement through the Suez Canal, or hitch-hiking on ships that pass 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 Red Sea marinas and other artificial moorings, in order to unveil the possible source and pathway 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 (Italy) and NIOF (Egypt) was carried out. A survey on the fouling species colonizing artificial substrates in 6 Red Sea localities from Qusier to Hurghada (NW Red Sea, Egypt) was conducted in summer 2017 by scraping docks, floating pontoons and buoys. In many cases bryozoans, crustaceans, molluscs and polychaetes that are considered alien species in the Mediterranean (about 15 species) were found, thus supporting the hypothesis that they might have been introduced by boats travelling from there. The fouling communities observed are also composed by some Indo- Pacific species that have not yet been reported in the Red Sea. These results raise a new question: is the Red Sea part of their natural biogeographic range, or have they been brought there artificially by boats?. 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.