Rapid assessment survey of non-indigenous and cryptogenic species in Tunisian marinas

A crucial first step in managing marine non -indigenous species (NIS) that pose a threat to native species, habitats or ecosystems is for countries to update their NIS lists. In the Mediterranean region, efforts to update these lists vary greatly from country to country. There is a notable disparity between the northern and southern coasts of this basin, which warrants attention to ensure a comprehensive assessment of the management and dissemination of NIS along the Mediterranean coasts. In this context, a rapid assessment survey was carried out along the Tunisian coasts in five marinas: Bizerte, Gammarth, Hammamet, Port El Kantaoui and Cap Monastir. NIS belonging to the five sessile macrozoobenthic groups Ascidiacea, Bryozoa, Porifera, Hydrozoa and Polychaeta in different substrata of these marina habitats were surveyed in May and December 2019. Here we report a total of twenty NIS and cryptogenic species with six new records in Tunisian marinas: Phallusia nigra Savigny, 1816; Clavelina oblonga Herdman, 1880; Ciona robusta Hoshino & Tokioka, 1967; Didemnum cf. vexillum Kott, 2002; Botrylloides cf. niger Herdman, 1886 and Bugula stolonifera (Ryland, 1960). Our findings suggest that it is important to monitor buoys when trying to detect NIS and cryptogenic species.