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Sea otters are crucial indicators of the health of our nearshore waters and coastal resources, from kelp forests to fisheries. What clues does the sea otter's decline hold for our knowledge of ecosystem and global change? U.S. and Canadian researchers have teamed together to  investigate.

  • The Investigation
    Explore the scene and hunt for clues in sea otters and the nearshore ecosystem
  • A Team Effort
    Meet the investigators and partners and see where they work
  • For Policymakers
    Retrieve memos and contacts explaining project implications for your region
  • For Media
    Download press kits and multimedia packages
  • For Scientists/Managers
    Look up detailed study plans, publications and briefings generated by project scientists

The serene nearshore waters of Big Sur, California. --Photographer: Ben Young Landis, USGS


The serene seashore where you’re sharing a family moment, gazing out at the horizon. The bobbing patch of kelp forest where you’ve just cast your line and bait. The blue Pacific waters where lazy estuaries and craggy gulches mix with the cool currents of the deep.

This is the world of the nearshore ecosystem -- chances are you’ve seen its natural beauty in photographs or on film, or you’ve been lucky enough to experience it in person or taste its bountiful harvests. It’s scene that can be found from the California coast to Washington, British Columbia and north through Alaska.

But how are these nearshore ecosystems and resources reacting to the ever-growing roster of threats to its function and health? With natural challenges like winter storms and decadal cycles, and human inputs like chemical pollution and expanding coastal cities, to unsolved factors like climate change and ocean acidification -- scientists need new clues and tools to assess the health of our nearshore waters.

The answer starts with sea otters.

A sea otter with a flipper tag. --Photographer: Monterey Bay Aquarium

Sea otters are the perfect indicator species to help us investigate our nearshore conditions. They live their entire lives within nearshore waters, dependent on its kelp forests and other habitats for food and shelter and rarely straying into the open sea. Sea otters don’t migrate, and individuals normally keep to a local home range and a specific diet.

But this dependence also means that a sea otter will be constantly exposed to whatever contamination or stressors are in its local environment -- pollutants flushed downstream from inland lakes, or food web disruptions from altered ocean trends. If a nearshore ecosystem is facing new challenges, sea otters likely will be our first indication of trouble.

And the signs are there. Sea otters have been protected from hunting since the fur trade bans a century ago. Some populations are now abundant and stable, while others are either declining or struggling to reach healthy numbers. Can these differences be explained by ocean influences, or by human impacts to adjacent landscapes? What do these trends say about the quality of the otters' marine habitat -- the same habitat which supports our fisheries and our recreational waters?

So that’s the mystery, and the 3,000-mile coastline from California to the Gulf of Alaska is our scene of investigation. Scientists from government agencies, aquariums and universities are working together as detectives -- uncovering evidence from DNA analysis, chemical signals, forensic examinations and even space satellite imaging -- to study the health of our Pacific nearshore waters.

Start exploring the clues here, or meet the research team:

Jump to Clues from Sea Otters --Photographer: Tania Larson, USGS Jump to Clues from the Food Web --Photographer: Steve Lonhart, NOAA Jump to Clues from the Landscape --Photographer: Ben Young Landis, USGS Jump to Piecing Together the Clues

Updated 2011.05.12

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