"This is because we have forgotten what we used to have," said Jeremy Jackson of the Scripps Institution of Oceanography. "We had oceans full of heroic fishliterally sea monsters. People used to harpoon three-meter long swordfish in rowboats. Hemingway's Old Man and the Sea was for real."
Myers and Worm said that the tendency in fisheries biology to use only the most recent data increased the problem of shifting baselines. These great fish are not only declining in numbers, but with intense fishing pressure they can never attain the sizes they once did. "Where detailed data are available we see that the average size of these top predators is only one-fifth to one-half of what is used to be. The few blue marlin today reach one-fifth of the weight they once had. In many cases, the fish caught today are under such intense fishing pressure, they never even have the chance to reproduce," said Myers.
In the 1980s Myers was a fisheries biologist with the Department of Fisheries and Oceans in Newfoundland. "No one understood how fast the decline happened at the endit was only a couple of years," says Myers. "The quotas had been too high. They refused to slow down because they had seen lots of little fish coming ina good year class. The little fish were caught and discarded and there was no future."
Fisheries' Stability Compromised Worldwide
Myers said the most recent findings raise critical questions at a much larger scale. "This isn't about just about one species," he said. "The sustainability of fisheries is being severely compromised worldwide."
At the Johannesburg World Summit on Sustainable Development last year, 192 Nations called on the global community to restore world fisheries stocks to levels that can provide maximum sustainable yield by 2015. The authors of this comprehensive new study say their results provide the "missing baseline" needed to restore fisheries and marine ecosystems to healthy levels.
Without this baseline information, most scientists and managers are hardly aware of the profound magnitude of change that took place at the beginning of almost every major fishery, they say. As a result, managers today are working hard to stabilize the last 10 percentoften unaware that the virgin biomass of their fishery was once ten times greater.
But there is some good news too: "In most regions we saw increases in faster-growing species which seemed to fill in for overfished stocks. This points to the recovery potential for the community at large," Worm said. "But unfortunately we often switch fishing pressure to species that are doing well, and drive them down in turn. This sabotages recovery."
The solution to this global problem is simple, said the scientists, yet it is extremely hard to do in practice. Recovery requires overall reduction of fishing mortality (the percentage of fish killed each year). This includes reducing quotas, reducing overall effort, cutting subsidies, reducing bycatch, and creating networks of marine reserves.
"A minimum reduction of 50 percent of fishing mortality may be necessary to avoid further declines of particularly sensitive species," Myers said. "If stocks were restored to higher abundance, we could get just as much fish out of the ocean by putting in only one-third to one-tenth of the effort. It would be difficult for fishermen initiallybut they will see the gains in the long run."
"We are in massive denial and continue to bicker over the last shrinking numbers of survivors, employing satellites and sensors to catch the last fish left," said Myers. "We have to understand how close to extinction some of these populations really are. And we must act now, before they have reached the point of no return. I want there to be hammerhead sharks and bluefin tuna around when my five-year-old son grows up. If present fishing levels persist, these great fish will go the way of the dinosaurs."
Sylvia Earle said the new research may have come just in time to awaken people to the seriousness of the situation. "We will never get back to what we had in the oceans 50 years ago, but we still have a small window of opportunity to save the last few big fish before they are exterminated," she said.
More Ocean Stories from National Geographic News
High-Tech Fishing Is Emptying Deep Seas, Scientists Warn
Study Calls Into Question Global Quotas on Bluefin Tuna
Poaching, Smuggling Threaten Abalone Colonies in South Africa
Asian Shark-Fin Trade May Be Larger Than Expected
Sharks Falling Prey To Humans' Appetites
North Atlantic Sharks on Sharp Decline, Experts Say
Leatherback Turtles Near Extinction, Experts Say
Fisheries Ebb and Flow in 50-Year Cycle, Study Says
World's Heaviest Bony Fish Discovered?
New Jellyfish Species Found
"Colossal Squid" Revives Legends of Sea Monsters
Extinction Near for Albatross, Experts Warn
Dolphins Deployed as Undersea Agents in Iraq
Belize Reef Die-Off Due to Climate Change?
Killer WhalesKilling Other Whales
Saving Sea Turtles With a Lights-Out Policy in Florida
Whales Win Right-of-Way in Atlantic Shipping Lanes
Belize, UN Try to Save Reefs and Help Fishers
Dolphin Researchers focus on Alboran Sea
Photographer David Doubilet on His Work
Manatee May Lose Endangered Status in Florida
SOURCES AND RELATED WEB SITES