Aliens in Egyptian waters. A checklist of ascidians of the Suez Canal and the adjacent Mediterranean waters

Checklists of the alien ascidian fauna of Egyptian waters are provided covering the Suez Canal, the adjacent Mediterranean waters and the Gulf of Suez. Enrichment in ascidian species of the Suez Canal seems to have been on the increase since 1927. The distinctly uneven distribution pattern in the Canal appears to be directly related to the ship traffic system. Earlier reports on alien ascidian species in the Mediterranean are compared and discussed. Of 65 species recorded from the Mediterranean waters of Egypt in all, four are Erythrean migrants and four potentially so. Polyclinum constellatum Savigny, 1816 is a new record for the Mediterranean Sea.