Global fishing trends point to a collapse of most wild seafood harvests by midcentury, according to a team of international researchers...
Global fishing trends point to a collapse of most wild seafood harvests by midcentury, according to a team of international researchers who pored through historical data, catch records and studies to document the decline of marine species all over the world.
The researchers found that harvests of nearly 30 percent of commercial seafood species already have collapsed. Without major changes in fisheries management, they say, the trend will accelerate.
“It looks grim, and the projections into the future are even grimmer,” said Boris Worm, a marine biologist and a lead author in the peer-reviewed study, which was published today in the journal Science.
But other scientists question that forecast.
“It’s just mind-boggling stupid,” said Ray Hilborn, a University of Washington professor of aquatic and fishery sciences.
“I’m worried about some areas of the world — like Africa — but other areas of the world have figured out how to do effective fishery management.”
For example, most of the harvests in the North Pacific off Alaska — where most Seattle fleets fish — are not in sharp decline.
Key findings
• Losses of marine populations and species are accelerating.
• Those losses can reduce the ocean’s ability to resist disease, filter pollutants and rebound from stress such as overfishing and climate change.
• As of 2003, 29 percent of commercially fished species had “collapsed,” meaning harvest rates were less than 10 percent of historic peaks.
• If the trend continues, almost all commercially fished species could collapse by 2048.
Less species diversity
Worm, from Dalhousie University in Halifax, Nova Scotia, led a 14-person study team that included researchers from Stanford University, Scripps Institute of Oceanography, Stockholm University, the University of British Columbia and other universities. They analyzed studies that looked both at coastal estuaries and at the broader areas of the ocean.
Their goal was to quantify the impacts of shrinking marine biodiversity on human welfare.
They concluded that declining species diversity could have profound impacts, creating more unstable marine ecosystems that are quicker to crash and slower to recover. For humans, the decline in diversity was tied to declining seafood harvests, water pollution and a stagnation of maritime economies. And as more species collapsed, they concluded, the overall ecosystems may unravel at a faster rate.
They define collapse as harvests of less than 10 percent of historic highs.
The researchers also found hopeful signs.
They looked at marine conservation areas where fishing is off limits or severely restricted. In those areas, they found marine species were able to increase, reversing previous declines.
The researchers also used past commercial-catch records to predict future harvest trends.
They found that in 1950, only six commercial seafood species worldwide had collapsed. By 2003, more than 2,200 species — 29 percent of all commercially fished species on the planet — had collapsed.
Based on that rate of decline, the study then projected that most world fisheries could collapse by 2048 if something isn’t done soon.
Some marine scientists who were impressed by the overall article were uncomfortable with that projection.
“They are flagging a really serious problem, but I don’t buy that extrapolation,” said Jane Lubchenco, a marine biologist at Oregon State University.
But that midcentury projection was highlighted Thursday as the researchers announced the study’s findings.
“News hook”
In a note to colleagues that was mistakenly sent to The Seattle Times, Worm wrote that the projection could act as a “news hook to get people’s attention.”
“One reason why nobody cares about marine biodiversity is that there seemed no clear end in sight,” he continued. “… Well, it’s time to wake up — IF the current trend continues we will see drastic consequences in our own lifetime.”
When asked about the e-mail, Worm said the 2048 projection is accurate, and he reiterated he is very confident that the trend could lead to a global fisheries collapse. He noted that the study’s prediction of worldwide collapse is based on an average fishery of the future, and that some fisheries could end up well above the dismal average.
Worm also is optimistic that the trend could be turned around with more marine conservation zones and other efforts.
“We have a whole portfolio of options,” Worm said. “What it takes is political will.”
Worm cited the North Pacific fisheries off Alaska as a success story, where harvest managers have avoided many of the mistakes made in other areas of the world.
The North Pacific yields the largest North American harvests, worth more than $2 billion annually.
Seafood Watch, a consumers’ guide to sustainable fisheries launched by the Monterey Bay Aquarium in California, lists Alaska pollock, salmon, halibut and some other North Pacific species as “best buys.”
U.S. management of the 200-mile zone off Alaska began in 1976, and was forged by distaste for years of unregulated foreign fishing off the state’s coast. A federal fishery council made some areas off limits and imposed a cap on fish harvests in the Bering Sea.
Still, there are some trouble spots.
Stocks of Pacific perch, for example, remain seriously depleted from overfishing. This year, there are new uncertainties about the stocks of pollock, the largest fishery in the North Pacific, and that could lead to new harvest restrictions.
Even so, Worm said that if Alaska management stays on course, the North Pacific could buck the global trend and continue to yield harvests past the midcentury.
“Alaska is the place where — for whatever reason — people early on started to steer away from the usual approach to overfishing, where you move on to the next species until you scrape the bottom of the barrel,” he said.
Hal Bernton: 206-464-2581 or hbernton@seattletimes.com
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