Scientific report shows presence of “alien species” from Australia in Moroccan waters

A recent publication in Mediterranean Marine Science reports the discovery of an Australian spotted jellyfish in Moroccan waters. Initially discovered by scuba divers and later washed ashore in 2017, this marked the species' first appearance in Moroccan territory, originating from the Indo-Pacific region.

The means by which it, along with 45 other "alien species," arrived in Moroccan waters remain unclear. But scientists suspect transportation via ships traversing the Suez Canal.

“In the Mediterranean, the most common pathway is Transport-Stowaway, with 23 alien species having been likely introduced through two vectors, hull fouling or ballast water,” according to the study.

Hull fouling is when barnacles and other crustaceans attach themselves to the hull of a ship and catch other marine life on their journey. Ballast water is water held in cargo ships to balance the boat. The water is released on arrival along with the living creatures who boarded on departure. 

The Australian spotted jellyfish’s venom is weak but it can deplete zooplankton potentially threatening the food source of local species. Despite limited data on its volume and threat to Morocco, concerns persist regarding other invasive alien species, which could significantly affect native biodiversity and ecosystem function.

“Despite the relatively low number of alien species in the Moroccan Mediterranean, a considerable proportion of them (31%) are species that have been classified as invasive in some part of their introduced range, having significant impact on native biodiversity and ecosystem functioning,” the researchers said.