Exploring California’s Marine Protected Areas: Elkhorn Slough


Elkhorn Slough
A placid morning on Elkhorn Slough  CDFW photo by P. Serpa

California estuaries, with their tidal flats, coastal marsh, eelgrass and brackish water are special places where fresh water flows to meet the salty Pacific Ocean. Elkhorn Slough is a large, iconic estuary near Moss Landing in Monterey County, known for its high species richness and habitat diversity. Combined, Elkhorn Slough and the smaller, adjacent Moro Cojo Slough make up the largest coastal marsh area between San Francisco Bay and Morro Bay.

This area is home to large eelgrass beds (a habitat-forming, underwater plant important to many estuary inhabitants) as well as over 135 species of resident birds, 200 species of migratory birds, 550 marine invertebrate and 102 fish species. The slough provides essential feeding and roosting habitat for heron rookeries, a small breeding population of western snowy plovers, nesting pairs of golden eagles, white-tailed kites, and other bird species. The tidal channels also serve as nurseries for juvenile fish, and a protective home for sea otters and harbor seals. The high densities of invertebrates and fish in these channels also serve as food sources for the slough’s large populations of birds and mammals.

Elkhorn Slough
Now part of the Elkhorn Slough Ecological Reserve and National Estuarine Research Reserve, a dairy barn adds to the picturesque scenery and reminds visitors of the current and historical uses common along the banks of the slough.   CDFW photo by P. Serpa

In addition to providing excellent habitat for marine species at various life stages and abundant food sources for local populations of fish, birds, and animals, the slough also functions as a filter and sponge for sediment and pollution from surrounding farms and other land uses. Commercial activities in this area are diverse, and include Moss Landing harbor (a large fishing port), properties hosting dairy farms or agriculture, three major highway corridors, a main north-south coastal rail line, and the largest electric power generating plant in California. The slough’s ability to filter pollution is especially valuable because the mouth of Elkhorn Slough opens into the Monterey Submarine Canyon, connecting land and marine systems through concentrated runoff from the entire watershed.

Environmental scientists from the California Department of Fish and Wildlife along with other natural resource management agencies and land conservation groups (National Oceanic and Atmospheric Administration, The Nature Conservancy, and others) have long understood the importance of sustaining healthy wetlands for critical ecosystem function and services, notwithstanding high levels of human use. Because of the high ecological importance of this area and the varied external influences, diverse management strategies are used to accommodate multi-use interests while simultaneously striving to conserve the estuary system. These strategies include three marine protected areas, a wildlife area, an ecological reserve, and a national estuarine research reserve. Each management area is unique in its objectives (with some geographic overlap) and encourages different activities.

Elkhorn and Moro Cojo sloughs are used by many different interests that are supported by different management areas.   map by CDFW GIS Lab

Fishing and clamming are popular activities in Elkhorn Slough State Marine Conservation Area and north of Kirby Park. Waterfowl hunting is common in select areas of the northern shores within the Moss Landing Wildlife Area. Hiking, wildlife viewing, photography, and guided excursions are excellent in the Elkhorn Slough Ecological Reserve and National Estuarine Research Reserve. Kayaking, paddle boarding, and boat tours are available in the Elkhorn Slough State Marine Reserve. Information regarding many of these tour services are found either at the reserve visitor center or in the Moss Landing community.

We encourage you to explore this wonderful area through self-guided activities or with one of the many guided tours available. With the high species diversity and dramatic beauty found in this natural ecosystem, fantastic recreational activities await, whether fishing, hunting, or just taking it all in.

logo post by Paulo Serpa, CDFW Research Analyst


Learn more about MPAs by diving into the
Exploring California’s Marine Protected Areas series!