Invasive and Alien Rhodophyta in the Mediterranean and along the Israeli Shores

Hundreds of marine organisms including algae, phytoplankton, zooplankton, sponges, Cnidarians, mollusks, worms, arthropods, and fish species have already migrated via the Suez Canal in Egypt since the Grand Opening in November 1869. The Lessepsian migration takes place mostly from the Red Sea to the Mediterranean. However, few species migrated in the opposite direction (the Anti-Lessepsian migration) (Golani and Ben-Tuvia, 1995; Golani et al., 2002). The factors that facilitate the mainly northwardly transport to the Mediterranean were well described by Por (1971, 1978) who claims that high salinity and high temperature in the Levant Basin of the Mediterranean increase the chances of success of Red Sea invaders. The fact that the Red Sea contains far more species when compared with the temperate fauna in the Mediterranean also contributes to the predominance of Red Sea organisms among Lessepsian migrants. In addition, the high salinities of the two bitter lakes along the canal, reaching 48‰ (Morcos and Messieh, 1973), make the traverse harder for Mediterranean than for Red Sea species, since the latter is considerably more saline. The fact that Indo-Pacific organisms show more versatile adaptation to various ecological niches helps them to compete successfully with Mediterranean species and occupy vacant ecological niches as well (Por, 1971). Other important reasons to the northern transport are the winds and the northward water current leading from the southern end of the canal to its north. These streams support species migration as animal eggs, larvae, and juveniles, and probably algal spores as well (Madl, 1999). International maritime traffic also plays an important role (as a transportation vector) conveying marine species all around the world through the ships ballast water (Nehring, 2002, 2005; Streftaris et al., 2005) or attached to the ships’ hulls (Verlaque et al., in press).