Shark thin soup

It has been slow to emerge and the animals win few public friends, but the global dramatic decline in shark numbers is being revealed. In the Gulf of Mexico oceanic whitetip sharks have declined by up to 99 per cent between the 1950s and the 1990s, and numbers of individuals in coastal species of the shark family here have declined by a similar amount between 1972 and 2002. In the northwest Atlantic several large shark species have been reported to have declined by more than 75 per cent in the 15 years since 1986. But for many other regions of the world few data on shark numbers are available. So the results of a new study from the Mediterranean are particularly alarming. Sharks here have undergone a massive decline over the last two centuries, scientists report, on the basis of a new study of historical records. Some species have shrunk by more than 99 per cent over the period, mainly due to fishing. A team of researchers from Dalhousie University and the Italian environmental protection agency in Livorno, led by Francesco Ferretti, used fishermen's notes and archive records to plot population trends of five top predatory sharks.The study is reported in the journal Conservation Biology. Sharks and their close relatives, the rays, are particularly vulnerable to over-fishing as they grow and reproduce slowly. " There is a long history of fishing in the Mediterranean, especially coastal fishing, " said Ferretti. " And until recently, these species were not valuable — they were caught as bycatch by boats chasing important species such as tuna — so they were declining without anyone noticing, " he said. There are 47 species of shark found regularly in the Mediterranean, of which 20 are top predators. Fishermen tend to regard them as pests, according to records amassed by the researchers. For five of the top 20 predators, the records — from traditional tuna traps, commercial boats and fishermen using rods and lines — were good enough to show that catches had been large enough to provide evidence of a substantial decline. The hammerhead population, they conclude, has declined by more than 99.99 per cent over the last 200 years. Feature Records show that hammerheads largely vanished from coastal waters around 1900; in the last 20 years they have barely been seen in pelagic zones either. The blue shark and the two mackerel sharks have also …