Presence of Caulerpa cylindracea (Chlorophyta) in the North of Strait of Gibraltar: Effectiveness of Citizen-Scientist in Detecting Invasion and Record in Atlantic European Coast

Presence of Caulerpa cylindracea (Chlorophyta) in the North of Strait of Gibraltar: Effectiveness of Citizen-Scientist in Detecting Invasion and Record in Atlantic European Coast

The presence of Caulerpa cylindracea Sonder was recorded for the first time within the Mediterranean Sea in Libya, 1990s. Since then, this alien species has invaded the Mediterranean basin moving from the Eastern basin towards the Atlantic Ocean. C. cylindracea displays aggressive spreading kinetics and generates negative impacts over native biota. In the present study, this species is first recorded for the Northern margin of the Gibraltar Strait and the Atlantic European coast, in the Marine Protected Area (MPA) of "Parque Natural del Estrecho". The closest localities where C. cylindracea had been recorded were: Almeria in 2014 on the European coast of the Alboran Sea, southern Spain 400 kilometres from this record and; Ceuta in 2010, on the African margin of the Gibraltar Strait. Considering the geographical proximity of Ceuta, and the maritime traffic between Tarifa (Southern Iberian Peninsula), and northern Africa, Ceuta is considered as the most likely origin of the invasion. Since data were collected by recreational divers trained to identify the species, it is a good example of the usefulness of citizen scientist networks in the early detection of biological invasions. Some eradication measures were performed over the located patches. However, although the invasion is incipient, the species is widely spread in the area, thus we should consider that Caulerpa cylindracea has been successfully established in this MPA and eradication measures are not feasible.