ZAGREB: Croatian marine biologists are struggling to save the largest Mediterranean clam from extinction after a precipitious fall in numbers which they say was probably caused by a deadly pathogen.

The clam, known as the noble pen shell or pinna nobilis, plays an important ecological role by filtering sea water and allowing other organisms to flourish. Its shell can reach as much as four feet (120 cm).

The first signs of a pathogen targeting the clams came four years ago off the coast of Spain, the biologists say. The spread of the pathogen may have been helped by rising sea temperatures related to climate change, though they cannot be 100 percent certain.

“After the first evidence of the mass mortality of pen shells in their habitat (off Spain), the disease quickly spread across the Mediterranean. In Croatia, in the southern Adriatic, we first spotted what was going on in May last year,” said Luka Katusic of the Croatian Institute for Environmental Protection. By the spring of 2020 the whole Croatian coast had been affected.

“Mortality is extremely high and it has been proven that in localities where the causative agent of the disease appears, it can cause 100pc death or extinction of pinna nobilis,” Katusic said.

A year ago the aquarium in the northern Adriatic city of Pula collected some 300 seemingly healthy specimens and put them in pools hoping to save them, but fewer than 30 remain alive.

Published in Dawn, September 19th, 2020