Scientists - Oceans On Edge Of Extinction Tipping Point - WP [View All]

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Dozens of biologists believe the seas have reached a tipping point, with scores of species of ocean-dwelling fish, birds and mammals edging towards extinction. In the past 300 years, researchers have documented the global extinction of just 21 marine species -- and 16 of those extinctions occurred since 1972. Since the 1700s, another 112 species have died out in particular regions, and that trend, too, has accelerated since the mid-1960s: Nearly two dozen shark species are on the brink of disappearing, according to the World Conservation Union, an international coalition of government and advocacy groups.

"It's been a slow-motion disaster," said Boris Worm, a professor at Canada's Dalhousie University who wrote a 2003 study that found that 90 percent of the top predator fish have vanished from the oceans. "It's silent and invisible. People don't imagine this. It hasn't captured our imagination, like the rain forest."

Compared with the many activists who have focused on the plight of creatures such as the ivory-billed woodpecker and the grizzly bear, relatively few have taken up the cause of marine species. Ocean dwellers are harder to track, some produce so many offspring they can seem invulnerable, and, in the words of Ocean Conservancy shark fisheries expert Sonja Fordham, often "they're not very fuzzy." Although a number of previous extinctions involved birds and marine mammals, it is the fate of many fish that now worries experts. The large-scale industrialization of the fishing industry after World War II, coupled with a global boom in ocean-front development and a rise in global temperatures, is causing fish populations to plummet.

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Large-scale fishing accounts for more than half of the documented fish extinctions in recent years, Nicholas K. Dulvy, a scientist while at the University of Newcastle's School of Marine Science and Technology in England, wrote in 2003. Destruction of habitats where fish spawn or feed is responsible for another third. Warmer ocean temperatures are another threat, as some fish struggle to adapt to hotter and saltier water that can attract new competitors. But nothing has pushed marine life closer to the edge of extinction more than aggressive fishing. Aided by technology -- industrial trawlers and factory ships deploy radar and sonar to scour the seas with precision and drag nets the size of jumbo jets along the sea floor -- ocean fish catches tripled between 1950 and 1992. In some cases fishermen have intentionally exploited species until they died out, such as the New Zealand grayling fish and the Caribbean monk seal; other species have been accidental victims of long lines or nets intended for other catches. Over the past two decades, accidental bycatch alone accounted for an 89 percent decline in hammerhead sharks in the Northeast Atlantic.

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http://www.washingtonpost.com/wp-dyn/content/article/2005/08/22/AR2005082200036.html