The Mediterranean's bluefin tuna population will be extinct in three to five years time if over-fishing is not stopped, the Italian chapter of Greenpeace has warned.
The environmental association claims that widespread tuna "plundering" means the number of bluefins being caught in the Mediterranean is twice the legal limit.
"These fish come to the Mediterranean from the Atlantic to breed and every year 60,000 tonnes are caught when they arrive, while the quota is 32,000," said Alessandro Gianni', the head of Greenpeace Italia's sea campaign.
"The species will be extinct here in three to five years unless the over-fishing is stopped at once.
"The bluefin's breeding grounds should also be turned into marine reserves to protect the fish during crucial parts of their life cycle".
Bluefin tuna mature relatively late in life, he said, which means populations are slow to grow back when depleted.
Gianni claims most of the fish are captured alive and taken to so-called 'tuna ranches'.
There they are fattened up before being exported to Japan, where they fetch high prices to be used for sushi.
He said illegal fishing practices, such as the use of drift nets, are common and that large quantities of immature tuna are being caught as well as adults.
"A few weeks ago we uncovered the presence of illegal drift nets on boats in Sicily and we sent photos to Agriculture Minister Paolo De Castro asking him to take action," he said.
Drift nets, which can be as long as eight kilometres, are blamed for causing widespread damage to sea life.
Dubbed the "walls of death" by critics, the nets are left to drift at sea entangling everything that swims into them, including non-targeted fish, dolphins, whales and sea turtles which die as a result.
Gianni' added that the high quantity of fish needed to fatten the tuna at these ranches was a strain on stocks of other species too.
Greenpeace and scientists are also worried about the effect climate change is having on the Mediterranean's biodiversity.
In April Silvio Greco of the Central Institute for Research Applied to the Sea (ICRAM) presented a study that showed the Mediterranean's deep water temperatures are increasing.
He said this suggests global warming is at work, because deep water temperatures are not subject to the temporary factors that cause surface temperatures to fluctuate.
He said the trend threatens to have grave consequences for marine flora and fauna.
"The Mediterranean accounts for just 0.8% of the planet's marine waters, but it is estimated to contain 9% of global biodiversity, so it is a highly delicate environment," he explained.
20% OF MEDITERRANEAN'S FISH ARE "IMMIGRANT" SPECIES.
Last year Rome university lecturers presented research showing that 20% of fish in the Mediterranean are now "immigrant" species.
Warmer water temperatures have encouraged these fish to move up from southern seas via the Suez Canal and the Strait of Gibraltar.
Experts believe the Mediterranean's own species, which are used to more temperate waters, are bound to suffer as a consequence.
Last week the National Institute of Geophysics and Volcanology launched a major project to monitor climate change's effects throughout the Mediterranean region.
Over 65 partner institutions from Europe, North Africa and the Middle East will take part in the CIRCE (Climate Change and Impact Research: the Mediterranean Environment) programme.
"Mathematicians, climatologists, agronomists, economists and IT experts will work together on this project and the results will be made available to the scientific community and to political decision-makers," said CIRCE Coordinator Antonio Navarra.
"This research will uncover the possible future scenarios caused by climate change and how best to mitigate the consequences".
