Scientists Map Extensive Human Toll on World’s Oceans
Contact: Robert Steneck (207) 581-3321; Tom Weber (207) 581-3777
ORONO — The first global study of the impact of human influence on marine ecosystems reveals that more than 40 percent of the world’s oceans are heavily affected by it and only a few remain untouched.
Robert Steneck, a professor at the University of Maine School of Marine Sciences and Darling Marine Center, was one of the 19 researchers who conducted the study at the University of California at Santa Barbara. Their paper, “The Global Map of Human Impact on Marine Ecosystems,” was published in the Feb. 15 issue of the journal Science and presented at a press conference a day earlier at the annual meeting of the American Association for the Advancement of Science in Boston.
By overlaying maps of 17 different activities, such as fishing, pollution and climate change, the scientists were able to gauge for the first time the cumulative human toll on the world’s seas. While past studies have concentrated largely on single marine ecosystems in isolation, or the effects of a single activity, this study synthesized the effects humans have on the entire ocean, from its coral reefs and seagrass beds to the continental shelves and the deep ocean.
“We scientists actually study a very small portion of the marine ecosystems,” Steneck says. “About 90 percent of our observations come from a fraction of the ocean.”
The researchers found that the most heavily affected waters include the North Sea, the South and East China seas, the Caribbean Sea, the Mediterranean Sea, the Red Sea, the Persian Gulf, the Bering Sea, several regions in the western Pacific and the east coast of North America.
The ecosystems most affected by human activity include coral reefs, seagrass beds, mangroves, seamounts, rocky reefs and shelves. Even the relatively pristine ecosystems near the poles face the risk of rapid degradation, the authors point out, as human activities spread into these regions and polar ice sheets disappear with global climate change.
And the human footprint present in Maine’s oceans, Steneck says, is big indeed.
“We have as disrupted a food web here as there is on the planet,” he says. “The ground fish are greatly diminished and we have very low biodiversity.”
The researchers suggest that their report, while troubling, should be regarded not as an admission of defeat but as a much-needed wake-up call for better ocean conservation measures in the future. And one of the most promising ways to achieve that in Maine, Steneck says, is through an area-based management approach in which the fishermen themselves take responsibility for the coastal zones that provide their livelihood.
“Just as farmers wouldn’t intentionally degrade their own land, fishermen are going to mind their own stocks more carefully because they have the most invested in them,” Steneck says. “The idea is to take back marine conservation one area at a time, by the fishermen who have the biggest stake in the process.”
To view and download the maps of human influence on the oceans, visit the National Center for Ecological Analysis and Synthesis website at