The findings are based on historic documents, data from fish markets and accounts of shark sightings, The Washington Post reported Monday.

Francesco Ferretti, a graduate student at Dalhousie University in Nova Scotia, told the U.S. newspaper sharks are being targeted because of Asian demand for shark-fin soup and to make up for a decline in other fish.

"At these levels, these sharks can be considered functionally extinct, meaning that they cannot perform their role of top predators in the Mediterranean marine ecosystems anymore," Ferretti said.

The findings are published in the journal Conservation Biology.