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Thursday, March 12, 2009

Overfishing of sharks hits entire marine food chain

Wow his paintings are really cool and sad. I did a Google images search.

Overfishing of sharks hits entire marine food chain
Thursday, March 12, 2009, Irish Times

SLIGO-BASED painter Diarmuid Delargy had his first encounter with a thresher shark as a young boy while out with his father on a small boat off the Antrim coast in the late 1960s. The experience left an indelible impression, and Delargy’s current exhibition simply entitled Shark is an ode to these astonishing creatures, the product of 450 million years of evolutionary perfection. Ode, perhaps, or requiem. My six-year-old wondered aloud as to why they looked so sad.

The artist’s own anger, etched in paint, is palpable. Mysterious, powerful and woefully misunderstood, sharks have long evoked a visceral reaction. This was skilfully exploited in 1970s blockbuster Jaws , which had a rogue great white terrorise (for no apparent reason) a coastal community. Peter Benchley, author of the eponymous book, in later years felt so bad at the pogrom his creation had helped stoke up against sharks that he became a prominent campaigner for their conservation.

Despite their terrifying appearance, you are in fact far more likely to be killed by a dog, pig, wasp or jellyfish, or for that matter be crushed by a vending machine, than you are to die in a shark attack. Worldwide, maybe 10 people a year are killed by sharks. The respect is not mutual; each year we kill around 100 million of them.

Globally, shark populations are crashing. “Humans are pushing shark species to extinction, with devastating impacts on the ocean ecosystem,” said marine wildlife specialist Elizabeth Griffin. “There is just no way for these species to withstand the direct pressure of man’s voracious fishing practices.”

Eliminating the top predator in any system creates what is called a trophic cascade. The species whose numbers sharks used to police, such as ray and skates, are now exploding in population. They in turn are wiping out scallops and other shellfish, and water quality is suffering as a result.

Reefs, too, are under assault as parrot fish, which are key to controlling algal growth on reefs, are being exterminated by the fish whose numbers are no longer being regulated by sharks. “We have literally chopped the top off the ocean food web,” according to Canadian marine scientist Julia Baum.

Some 90 per cent of all the large predatory fish in the world’s oceans have now been eliminated. It would be facile to imagine that such a profound reordering of marine life on earth would fail to produce far-reaching consequences.

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