The invasive ascidian Ciona robusta recorded from a Red Sea marina

The solitary ascidian Ciona intestinalis is among the most damaging of invasive fouling species in the world. It is mostly known from cold-water or temperate environments, where it is able to form dense aggregations. We present the first record of C. intestinalis type-A, now recognized as C. robusta, from the Eilat marina, Israeli Red Sea coast. Several individuals found fouling the bottom of the floating docks in March 2015 were identified using both mitochondrial sequencing and morphological tools. Periodical surveys revealed some of them with full gonoducts, and small individuals appeared two months later, indicating a reproductive population. The extremely high salinity and temperature at the Eilat marina indicates the wide environmental tolerance of this species. Since the only other report from this region dates to 100 years ago, from a dredging vessel at the entrance to the Suez Canal, and it has not since been recorded from any natural substrates in the region, it should be considered a non-indigenous species in the Red Sea.