Just when you thought it might be unsafe to swim in the tuna-farm infested Mediterranean, a new scientific study has found that sharks have infinitely more to fear from humans, than humans from sharks.
A research project conducted by the Lenfest Ocean Programme, and published in Conservation Biology on 11 June, revealed this week that Mediterranean shark populations have dwindled by 97% in abundance and catch weight over the past 200 years.
Of the estimated 20 large shark species to inhabit the Mediterranean, only five were registered in sufficient numbers to feature in this study. Of these, the hammerhead has registered the sharpest decline, followed by the blue shark, two species of mackerel shark, and the thresher shark.
The latter, which is considered harmless to humans, was the only shark species observed in coastal waters.
The blue, hammerhead and thresher sharks were all classified as “Vulnerable” according to the latest IUCN-World conservation Union Red List Criteria for extinction risk. Two mackerel sharks, the porbeagle and shortfin mako, were classified as “critically endangered”.
Many other large sharks are classified as “Data Deficient”. This category also includes the world’s most famous and feared marine predator: the great white shark.
Despite the fact that at least three large specimens have been landed in Malta over the past 30 years, the fish made famous by Steven Spielberg’s ‘Jaws’ is in fact believed to be a vagrant in the Mediterranean.
Coupled with the vulnerability of another of top marine predator, the bluefin tuna, the extinction of any resident shark species may have serious consequences for the ecosystem as a whole.
“The loss of top predators such as sharks in other sectors of the Atlantic has resulted in changes to the ecosystem,” main author Francesco Ferretti said. “These changes are unpredictable and poorly understood, but given the decline in Mediterranean shark numbers, there is cause to be seriously concerned.”
Overfishing is believed to be among the main reasons for the decline among shark species. There are currently no catch limits for commercially fished shark species in the Mediterranean Sea, and the study also notes that a comprehensive monitoring program for fisheries has been difficult to implement because of the small and localised nature of fisheries and the large number of countries bordering the sea.
In Malta’s case, most landed sharks tend to be bycatch of tuna, swordfish and other targeted species, although there is limited commercial fishing of dogfish (‘mazzola’).
The European Commission’s decision this week to close down the bluefin tuna fisheries as of 16 June may help towards alleviating the pressure on Mediterranean shark species.
But until the local shark population starts to recover, the most dangerous creature to inhabit Maltese waters this summer is likely to remain the jet-ski driver.

rvassallo@mediatoday.com.mt