Recent occurrence and expansion of the non-indigenous alga Rugulopteryx okamurae in Morocco (Mediterranean and Atlantic shores)

Seaweed invasions are known as one of the main threats to coastal resources and biological diversity. The brown alga Rugulopteryx okamurae is one of the non-indigenous species that became invasive more recently. The occurrence of this common species of the warm temperate western Pacific Ocean, is confirmed for the first time in the Moroccan Atlantic coast. It was previously reported only from the M’diq beach (Alboran Sea-Morocco), and this study confirm that the northwest of Morocco, including Mediterranean Sea and Atlantic Ocean, is currently experiencing a wide invasion and massive proliferation of this non-indigenous brown alga¸ with a distribution depth up to 20 m from the intertidal zone. Substantial amounts of R. okamurae have also been cast on the beach as wrack.