50 Years Of Fishing Catch Data Show Huge Reduction In Marine Biodiversity

[hatrack]

Researchers who studied decades of catch records from Japanese fishing fleets say fishing has greatly reduced the diversity of fish in the world's open oceans, leaving ocean ecosystems less resilient against environmental changes like global warming. The scientists, who report their findings in today's issue of the journal Science, say it has been known for some time that fishing has reduced species diversity in coastal areas. But they say their study is the first broad look at diversity across open oceans.

The Japanese data records the catches in 50 years of fishing for 15 species of tuna and billfish like marlin and swordfish. But the researchers cross-referenced this information with data collected about more than 140 species by American and Australian government agencies in the 1990's, and the results suggest their conclusions apply more widely. Boris Worm, a biologist at Dalhousie University, in Nova Scotia and a lead author of the paper, said, "The oceans have been drained of species, basically." He said that more must be done to protect areas where diversity persists.

Dr. Worm and another author of the new study, Ransom A. Myers, also of Dalhousie, reported in 2003 that industrial-scale commercial fishing had reduced the ocean's populations of large predatory fish by 90 percent. That study also involved data from Japanese fleets. In many areas, the researchers say, species diversity has fallen by half since the 1950's, meaning that boats now typically catch half the number of tuna and billfish species they did then. "It doesn't mean that all those species are extinct," Dr. Myers said in an interview. But he said the fact that they are not being caught "is pretty dramatic."

Daniel Pauly, who heads the Fisheries Center at the University of British Columbia and who was not involved in the research, said it was interesting that the researchers could "tease out the long-term trend" from normal diversity variations in space and time. But he noted that they concentrated on relatively few species. The researchers said fishing records show how areas with high diversity in the 1950's have been shrinking in the years since. The area between northern Australia and Indonesia used to be one of these areas, Dr. Worm said. But he said the area of robust diversity "just got smaller and smaller till it became indistinguishable from the rest of the ocean."

EDIT

http://www.nytimes.com/2005/07/29/science/29fishing.html?pagewanted=all

[Boomer]

1. No comment

I'm running out of things to say -- yet another sign of the die-offs due to overconsumption and environmental degradation.

So instead, let me take this opportunity to thank hatrack for all the wonderful science reports which he brings to this forum.

Thanks!