First record of the invasive Rhodophyte Hypnea cornuta (Kützing) J. Agardh 1851, in the Northern Tunisian coast (Bizerte lagoon, West Mediterranean Sea)

The rhodophyte Hypnea cornuta is a species native to the Indo-Pacific Ocean. It has been introduced into the Mediterranean since the 19th century in Greece, then has widely spread in the eastern Mediterranean subregion. The first record of H. cornuta in Tunisia was in the southern coast, at Djerba. This paper aims to report for the first time the detection of this species in the North of Tunisia (Bizerte lagoon), in May 2019. Thalli of H. cornuta were sparse, and the coverage area was less than 5 %. This finding of H. cornuta in Bizerte lagoon reveals its expansion in the western Mediterranean basin, and the main vector of this expansion is likely large commercial vessels and recreational boats.