West Coast Threatened by Human Activity

New Map Shows Cumulative Human Impact on Regional Ocean Ecosystems

Researchers at the National Center for Ecological Analysis and Synthesis (NCEAS) have produced a map that depicts the cumulative impact of humans on ocean areas off the West Coast. The map was published online, May 11, in Conservation Letters , a scientific journal, and shows every single spot on the West Coast to be annually affected by 10 to 15 human activities. Ben Halpern, a marine ecologist at NCEAS, was quoted in a press release as saying, “The results are a wake-up call. We are significantly affecting the oceans.”

Halpern and Kim Selkoe were the lead scientists in the two-year study. They first gathered quantitative information about human activities and compared the effects they had on different marine ecosystems. For example, they discovered that fertilizer runoff has a larger effect on salt marshes than it does on rocky reefs.

This data was then combined with information on the severity of 25 different human influences - such as commercial and recreational fishing, land-based pollution, and commercial shipping - to determine the “human impact score” of each location along the West Coast. Halpern says that while many studies focus on just one of these ecological stressors, the NCEAS study reflects the cumulative impact of each of the activities.

The map reveals the hot spots of cumulative impacts to be coastal areas near urban centers and watersheds with a large amount of land-based pollution, such as Los Angeles, San Diego, and the Oregon coastline. They found the San Francisco Bay and Puget Sound to be the most heavily impacted regions, citing climate change, fishing, and commercial shipping to be the biggest threats. “Puget Sound and the San Francisco Bay Area are heavily populated areas that have a lot of pollution, a lot of commercial shipping, and fishing,” Halpern told The Independent. “When you lay all these things on top of each other, it makes a lot of cumulative impact.”

Santa Barbara is somewhere in the middle of the chart, according to Halpern. While the ocean around some islands are in good shape and the region as a whole is nowhere near as bad as some other areas, our coast is by no means pristine. The cleanest areas are places with very little population density, such as the Northern California coast and Washington’s Olympic Peninsula.

Halpern says their research shows that a more comprehensive ecosystem-based management is more effective at protecting and sustaining ocean health, and that it can provide valuable guidance for efforts around the world. Philip Taylor, the section head in the National Science Foundation’s Division of Ocean Science, said that the study provides insight into which activities can continue without harming the ocean, and which ones need to be stopped or moved to a less sensitive area. He hopes that the map will help focus attention on the hot spots where better environmental management is needed.

Ryan Neal is an Independent intern.

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