« December 2006 Table of Contents
Biodiversity study rattles buyers, fisheries
- Steven Hedlund
December 01, 2006
U.S. and international officials are dismissing the findings
of a study published in the Nov. 3 issue of the journal Science
that projects the world's commercial fisheries will collapse by
2048 unless biodiversity preservation and ecosystem management
The four-year study claims the loss of biodiversity due to
overfishing, pollution and climate change is "profoundly"
reducing the abilities of the oceans to produce seafood and of
marine populations to recover from adversity. Titled "Impact of
Biodiversity Loss on Ocean Ecosystem Services," the study is
the first to analyze all existing data on fisheries and
ecosystems worldwide, claim its U.S. and Canadian authors.
"Basically, we found that the productivity of an ecosystem …
declines when species are lost," says lead author Boris Worm,
assistant professor of marine biology at Dalhousie University
in Halifax, Nova Scotia.
Worm correlates the productivity of an ecosystem without all
of its species to a car functioning with missing parts.
"If you throw out the gas pedal and steering wheel, the car
doesn't run," says Worm. He was surprised but pleased the study
received a lot of media attention because "it shows people care
so much about seafood and the oceans."
But the study touched a nerve with seafood professionals,
who were asked by family and friends if they were going to have
jobs in 2048. They're also concerned that the Science study
will overshadow the Institute of Medicine and Harvard School of
Public Health studies released
in October, which touted the
health benefits of
eating a variety of seafood twice a week,
and scare consumers away from eating seafood.
"We don't want people to not eat seafood because they think
the world is going to hell in a hand basket," says Steve
Murawski, chief scientist of the National Marine Fisheries
Service in Silver Spring, Md. He says the study is flawed
because it uses catch data instead of biomass data, and catch
data is "rarely" an accurate indication of a marine
"This doomsday scenario certainly doesn't gibe with what
we've observed in
the United States," says Murawski.
According to NMFS' annual report on the status of U.S.
fisheries released in June, 74 percent of the 206 stocks and
multi-species groups were not overfished (i.e. the stock's
population is above the target for sustainability) in 2005, up
from 72 percent in 2004, while 81 percent of the 237 stocks
were not subject to overfishing (i.e. the catch
is below the
target set in
the fishery's management plan) in 2005, the same
as in 2004.
"In stating that all exploited [species] will collapse by
2048, the authors made a simple extrapolation of their results
across the next 40 years. This is statistically dangerous,"
says Serge Garcia, director of the Food and Agriculture
Organization's fishery resources division.
"This extrapolation relies on a business-as-usual forecast
scenario," he explains. "For such a massive collapse to happen,
it would require reckless behavior by all industries and
governments over the next four decades, not to mention the
economic forces that would discourage this from happening."
Global seafood consumption is projected to reach 180 million
metric tons by 2030, says Garcia. Wild fisheries are expected
to continue to yield about 90 million metric tons a year.
Aquaculture is expected to fill the void, with production
doubling to 90 million metric tons a year by 2030.
Worm says he's "convinced" the world's commercial fisheries
will not collapse by 2048.
"It's not too late to turn it around," he says, "and we
Worm points to Alaska and Iceland as examples of areas where
fisheries and ecosystems are well managed. But he says poorly
managed fisheries still outnumber well managed fisheries
The Science study was funded by the National Science
Foundation, University of California and UC Santa Barbara.
- Steven Hedlund