Pacific Nearshore Project

Science Center Objects

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? WERC's sea otter team and U.S. and Canadian researchers have teamed together to investigate. 

Relevance to USGS Missions:

This research project has direct relevance for the Wildlife program of the Ecosystems Mission Area (ECO), which works with others to provide the scientific understanding and technologies needed to support the sound management and conservation of our Nation's biological resources. Specifically, we are developing and utilizing a variety of methodological and analytical tools to understand the structuring of ecosystems by sea otter populations and to predict the ecological consequences of management practices and as well as anthropogenic changes on these ecosystems.

The serene nearshore waters of Big Sur, California (WERC)

The serene nearshore waters of Big Sur, California.(Public domain.)


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 sea level rise and ocean acidification -- scientists need new clues and tools to assess the health of our nearshore waters.

The answer starts with sea otters.

WERC sea otter

(Credit: Monterey Bay Aquarium. Public domain.)


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.


  • To understand how sea otter recovery affects nearshore benthic communities, to describe the functional role of sea otters and other top predators in ecosystem resilience, and to develop mechanistic models of food web dynamics that can be used to identify vulnerabilities of nearshore ecosystems to emerging threats.