The blue swimmer crab, a marine alien species, recently caught in Maltese waters. Photo: Joseph Bezzina

A crab never recorded in Maltese waters was caught last week by an amateur fisherman in three-metre deep water.

It is a blue swimmer crab with a 10cm wide upper shell normally found in the Indian and West Pacific Oceans.

“This species has been previously recorded in Sicilian waters and the Levitan Basin, but never in Maltese waters,” said marine biologist Alan Deidun.

“It is believed to have come into the Mediterranean from the eastern flank, through the recently-opened Suez Canal.”

The spread of such species is a growing phenomenon especially following the opening of the expanded Suez Canal in Egypt earlier this month. The wider canal allows ships to travel faster and species attached to the hulls of the vessels passing through it have a greater chance of surviving the trip.

According to a recently-published review, half of the alien species found in Maltese seas during the last century have been spotted in the last 14 years.

“The review of records of different marine alien species from Maltese waters, conducted by the Department of Biology at the University of Malta, shows there are now 66 alien species recorded,” said Prof. Deidun.

No studies on the interaction between this crab species and other indigenous marine species have been conducted so far.

More information on this finding will be published in a scientific journal in the coming months.