Be nicer to sharks
source : The Week Scientific Reporting Staff The Week
Be nicer to Sharks.
They are viewed as our natural enemies, but we need the big predatory sharks to survive, not least to protect the humble scallop. Experts have warned that the drastic decline of shark numbers is having a knock-on effect on a whole range of smaller species, reports The Guardian. Ecologists from Dalhousie University in Nova Scotia have found that overfishing the largest predatory sharks (such as bull, hammerhead, dusky, and great white sharks) along the Atlantic coast of America has led to an explosion in the populations of the fish they would normally prey on, such as ray and skate.
If those fish are the winners, the losers are the species that lie immediately beneath them in the food chain, namely scallops, oysters, and clams. These are disappearing at such a rate that their populations, say the researchers, may never recover. According to the new analysis, the numbers of tiger sharks along the Atlantic coast have declined by 97% since the mid-Eighties, while hammerhead shark numbers are down by 99%. By contrast, the east coast cownose ray population is growing at 8% a year, with its total population in the region estimated at around 40 million.