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Conflicting
Data
Dependent on voluntary reports by individual nations, the
FAO global fisheries data are subject to inaccuracies and
vagaries. So Reg Watson - an expert in ecological modeling
- and his colleague Daniel Pauly at the Fisheries Centre at
the University of British Columbia used ecological modeling
to double-check the numbers.
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Pauly and Watson's data reveal there are a lot fewer fish
than once thought. |
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Watson
and Pauly divided the planet into about 260,000 sections -
or cells -each one measuring 30 minutes of latitude by 30
minutes longitude. Then, using a variety of biological, ecological
and historical data, the researchers determined how much and
what kinds of fish each cell could produce. Pauly and Watson
distilled information from sources ranging from satellite
images to natural history museums to compile a model of the
oceans' productivity.
"You
can work out what factors explain why some areas have higher
catches than others - the depths of the world's oceans, the
primary productivity [of plankton], the temperature of the
water," says Watson. "When you're finished you have a pretty
good model explaining why you, for example, get better catches
off the coast of Chile and Peru than other places."
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The ever-declining
numbers of fish, combined with the well-documented decrease
in average size and age of fish caught leave little scientific
doubt that "we've had the best of the world's oceans,"
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Then
the researchers superimposed the FAO's figures over their
own data, comparing the ecological capacity of 176,000 cells
to the reported catches in each one.
"When
we finished creating such a model, we were left with places
that just don't fit. And one of those places was an area of
the South China Sea where China has sole access."
The
out-of-whack numbers indicated that the Chinese could only
have been catching about half of what they were reporting.
Why the dramatic inflation? In their letter to the scientific
journal Nature, Pauly and Watson posit that China's socialist
economy encouraged the inflated reports. The scientists note
that "Chinese officials, at all levels, have tended to be
promoted on the basis of production increases from their areas."
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The US, Japan, India and China are the worlds biggest
fish producers. |
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China
also wanted to appear conservation-minded internationally,
and so declared a "zero-growth policy" in 1998. The result
- catch reports for 1999, 2000 and 2001 have been precisely
the same as for 1998. "There's
two ways of looking at it," says Watson. "One is to stop people
from fishing and the other is to just change the numbers.
We believe it's the second."
Officially,
China denies Pauly and Watson's conclusions, claiming that
there is no incentive to over-report and that the nation's
catch is larger because the count includes species left out
by other countries - such as crab and jellyfish. But, according
to Watson, other studies and anecdotal evidence from within
China support his own findings. While China may never officially
acknowledge any catch inflation or data fixing, the international
attention given to Pauly and Watson's work may nonetheless
inspire the Chinese to report more accurately. Why does it
matter?
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Photos: Reg Watson
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