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Elkhorn Slough State Marine Reserve/State Marine Conservation Area

winding waterways form an coastal estuary

Overview

Elkhorn Slough State Marine Reserve (SMR) and Elkhorn Slough State Marine Conservation Area (SMCA) are marine protected areas (MPAs) located within Elkhorn Slough, a large estuary east of Moss Landing and inland from Monterey Bay. The SMR covers nearly three square miles and the SMCA almost a quarter of a square mile. Together, they protect numerous habitats including tidal mudflats, marshes, eelgrass beds, and beaches.

These habitats are vital for many species including bat rays, leopard sharks and topsmelt; invertebrates, including ghost shrimp, oysters and moon snails; marine mammals including harbor seals, sea lions and sea otters; and more than 340 species of birds such as white-tailed kites, Caspian terns, and American white pelicans. Much of the SMR overlaps the Elkhorn Slough National Estuarine Research Reserve, which existed before the MPA implementation and is managed by the California Department of Fish and Wildlife in partnership with the National Oceanic and Atmospheric Administration, with considerable support from the Elkhorn Slough Foundation. With multiple layers of protection over many years, the Elkhorn Slough MPAs are an excellent destination for wildlife lovers, with abundant marine and avian life, stunning scenery, and calm waters. Kayaking is extremely popular here, attracting thousands of people each year.

Regulations

Elkhorn Slough SMR

It is unlawful to injure, damage, take, or possess any living, geological, or cultural marine resource.

California Code of Regulations Title 14, Section 632(b)(70)

Elkhorn Slough SMCA

It is unlawful to injure, damage, take, or possess any living, geological, or cultural marine resource, EXCEPT:
Recreational take of finfish by hook-and-line only, and clams from the slough’s north shore near the Moss Landing State Wildlife Area, is allowed.

California Code of Regulations Title 14, Section 632(b)(71)

Quick Facts

Elkhorn Slough SMR

MPA size: 2.72 square miles

Shoreline span: 0.7 miles

Depth range: 0 to 10 feet

Habitat composition:

  • Estuary: 1.65 square miles
  • Eelgrass: 0.03 square miles
  • Coastal marsh: 3.99 square miles

Elkhorn Slough SMCA

MPA size: 0.22 square miles

Shoreline span: 0.10 miles

Depth range: 0 to 10 feet

Habitat composition:

  • Estuary: 0.11 square miles
  • Eelgrass: 0.01 square miles
  • Coastal marsh: 0.44 square miles

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Video Gallery

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Related Information

About Elkhorn Slough State Marine Reserve/State Marine Conservation Area

Natural History

a belted kingfisher flies high against a clear blue sky, this bird specialized for fish hunting has a thick sharp bill, white underbelly feathers are broken up by a red and black belt of feathers, the tips of wings are have black and white checker markings
Belted kingfisher near Elkhorn Slough SMR. photo © M. Hawk, CC BY-NC 2.0

Elkhorn Slough is situated on the inland edge of Monterey Canyon, which plunges more than a mile deep, reaching nearly seven miles inland from the coast. Originally, a river flowed through Elkhorn Valley to Monterey Bay when the sea level was almost 400 feet lower than it is today.

When the sea level began to rise approximately 18,000 years ago, ocean water flooded the area where the river emptied into the sea, creating Elkhorn Slough. Elkhorn Slough, like other estuaries, is characterized by quiet waters protected from the pounding surf, creating a calm backwater environment with muddy shores. Many of the invertebrates that form the basis of the food web live in the mud. These animals have evolved to withstand large daily fluctuations in salt, temperature, and oxygen. Flatfishes, bat rays, leopard sharks, and the longjaw mudsucker are some of the fish that roam the channels and waterways of Elkhorn Slough, while harbor seals and sea lions foray into the slough to hunt and haul out on the muddy banks at low tide.

Elkhorn Slough also boasts the greatest number of threatened southern sea otters in the world and was the first estuary to be re-colonized by the mammals. This estuary is designated as a Wetland of International Importance under the Ramsar Convention and classified as an Important Bird Area by the Audubon Society for its critically important wetland habitat and location along the Pacific Flyway. In spring, look for ruddy turnstones, pigeon guillemots, and sooty shearwaters. Summer is a great time to look for Caspian terns, while fall and winter months offer ample opportunity to see flocks of surf scoters, black-bellied plovers, western sandpipers, and marbled godwits. At peak times, Elkhorn Slough may have an estimated 30,000 seabirds and shorebirds utilizing its calm waters and emergent vegetation for food and shelter.

Cultural History

floating on gray ocean water, with its feet cross a sea otter looks right at the camera, its slick brown fur is contrasted with the light tan fur around its face, under its triangular black nose a couple dozen thick whiskers mask its black lips they appear to curve into a smile
Sea otter in Elkhorn Slough SMR. photo © B. Passarelli, CC BY-NC 2.0

For centuries, Native American Tribes in California have relied on marine and coastal resources. Many Native American Tribes in California continue to regularly harvest marine resources within their ancestral territories and maintain relationships with the coast for ongoing customary uses. The area around Elkhorn Slough is within the historical range of Ohlone, or Costanoan, peoples. They gathered mussels, clams, and oysters from the mudflats and hunted rays and fish. Today, the Ohlone maintain a presence along the Central Coast, with individuals living throughout the region and continuing traditional practices.

The first Spanish contact was the Cabrillo Expedition of 1542, with European settlement beginning in the Mission Era of the 1700s. In 1848, a boom in population, driven by the gold rush, created a dramatic increase in demand for food. In 1866, a 61-meter wharf and warehouses were built in Moss Landing for whalers, fishermen, and salt pond operators to store products to be transferred to schooners before transport. To reclaim the wetland for farming, draining of the slough began in the 1900s. In the 1940s, the harbor mouth was fortified by blasting through the barrier dunes, providing a safe harbor for the commercial fleet and drastically changing water circulation within Elkhorn Slough.

Restoration of the Slough began in 1971 when the Nature Conservancy started buying land along the upper Elkhorn Slough to protect remaining estuary habitat. Soon thereafter, the California Coastal Commission nominated Elkhorn Slough for federal estuarine sanctuary protection. With the 1980 purchase of Elkhorn Dairy lands, CDFW created the Elkhorn Slough Ecological Reserve, which is now the Elkhorn Slough National Estuarine Research Reserve. Today Elkhorn Slough and Moss Landing Harbor support thriving economies in tourism, commercial fishing, and marine and coastal research, demonstrating that these three types of activity can coexist sustainably.

Recreation

a flock of elegant terns skim the green blue water which meets rolling brown hillsides on the horizon, a pair ride atop a yellow kayak amongst the birds of Elkhorn Slough
Kayakers surrounded by elegant terns in Elkhorn Slough SMR. photo © B. Henderson, CC BY-NC 2.0

Elkhorn Slough offers a wide array of exciting recreational opportunities, including wildlife viewing, kayaking, duck hunting, and nature tours. While no take is allowed within the SMR, there are still plenty of other recreational activities for visitors. Many birders consider Elkhorn Slough one of the best bird viewing locations on the West Coast. For nature lovers and wildlife photographers, the abundant sea otters, sea lions, and harbor seals all but guarantee excellent observation opportunities. Hiking trails are accessible at the Elkhorn Slough National Estuarine Research Reserve Visitor Center and the Moss Landing Wildlife Area.

An alternative way to experience Elkhorn Slough is by boat. Several kayak rental and boat tour companies are located off Highway 1 and provide opportunities to explore otherwise inaccessible parts of the wetland and see wildlife from incredible vantage points. All take is prohibited within the SMR, but recreational anglers are welcome to fish for finfish by hook-and-line within the SMCA. Clamming is also permitted in the SMCA, but limited to the north shore, in the area adjacent to the Moss Landing State Wildlife Area.

Coordinates

Elkhorn Slough SMR

This area includes the waters below mean high tide within Elkhorn Slough lying east of longitude 121° 46.400′ W. and south of latitude 36° 50.500′ N.

California Code of Regulations Title 14, Section 632(b)(70)

Elkhorn Slough SMCA

This area includes the waters below mean high tide within Elkhorn Slough east of the Highway 1 Bridge and west of longitude 121° 46.400′ W.

California Code of Regulations Title 14, Section 632(b)(71)

Downloads for Elkhorn Slough State Marine Reserve

Map

Map of Elkhorn Slough State Marine Reserve - click to enlarge in new tab

Facts, Map & Regulations

MPA fact sheet - click to enlarge in new tab

Downloads for Elkhorn Slough State Marine Conservation Area

Map

Map of Elkhorn Slough State Marine Conservation Area - click to enlarge in new tab

Facts, Map & Regulations

MPA fact sheet - click to enlarge in new tab