Twelve non-indigenous species discovered in Maltese waters

A new large-scale study has discovered twelve new alien species in Maltese waters, the largest number from all the countries studied.

The research, published this month in a paper entitled “A massive update of non-indigenous species records in Mediterranean marinas”, is the first major comprehensive study of the entire Mediterranean sea, which is a popularly known alien species hot-spot. A total of 51 such species have been discovered.

The study also discovered three completely new non-indigenous species which were previously not known to have invaded the sea, which is a significant finding considering how well-studied the Mediterranean already is.

The research involved the sampling of 600 boat hulls from 34 yacht marinas across Spain, France, Italy, Malta, Greece, Turkey and Cyprus, with the Maltese yacht marinas sampled in Msida and in the Grand Harbour area.

Alan Deidun, Associate Professor of Geosciences at the University of Malta and one of the co-authors of the paper, said that the focus has traditionally been on commercial shipping as the main route through which alien species are introduced into the Mediterranean. This study, however, focuses on recreational vessels berthed in yacht marinas, and, importantly, recognises this as a new route of invasion.

“Through this pan-Mediterranean study, we have identified yacht marinas catering for recreations vessels, as stepping stones for the invasion of marine aliens species,” Deidun said.

He explained that the findings had implication for the management of alien species, especially since the EU was moving towards attempting to control the introduction of non-indigenous sea creatures. Some alien species become invasive and displace local indigenous species, while others do not have a negative effect and add to the Mediterranean’s biodiversity.

There are an estimated 1.5 million recreational boats in the Mediterranean, he said, and so it would be difficult to counter the effects such massive traffic volumes had on introducing foreign species.

“Anti-fouling paint on yachts are to an extent effective in preventing sub-aquatic organisms from sticking to the hull, although they don’t completely eradicate the problem. However, other objects in yacht marinas, such a buoys, do not have anti-fouling paint applied to them. One measure which might be considered is cleaning buoys once a year,” he added.