Tidal Exchange, Fall 2023

Tidal Exchange newsletter of the elkhorn slough foundation

RECONNECTING OYSTERS & PEOPLE Kerstin Wasson Research Coordinator, Elkhorn Slough Reserve

A

t dawn on a midsummer low tide, I kneel to pick up a native oyster on the banks of Whistlestop Lagoon. This is something people have done in Elkhorn Slough for millennia— (continued on page 4)

fall 2023

Elkhorn Slough Foundation board of directors Bruce Welden President

Robert Hartmann Vice President

Tara Trautsch Secretary

Anne Secker Treasurer

Anne Olsen

Past President

Gary Bloom Judith Connor Terry Eckhardt Sandy Hale Emmett Linder Kent Marshall Hon. Susan Matcham Laura Solorio, MD David Warner Mark Silberstein

Executive Director

The mission of the Elkhorn Slough

RESERVE UPDATE

Bringing Back Our Marshes

Monique Fountain, Tidal Wetland Program Director

Foundation is to conserve and restore Elkhorn Slough and its watershed.

We see Elkhorn Slough and its watershed protected forever— a working landscape where people, farming, industry, and nature thrive together. As one of California’s last great coastal wetlands, Elkhorn Slough will remain a wellspring of life and a source of inspiration for generations to come.

PO Box 267, Moss Landing California 95039 tel: (831) 728-5939 fax: (831) 728-7031 elkhornslough.org Tidal Exchange Ross Robertson, Editor printed on recycled paper © 2023 Elkhorn Slough Foundation

HESTER MARSH Phase III of the Hester Marsh Restoration project is currently underway at Seal Bend. This area of the slough was historically diked and drained, causing the land to subside by about two feet and leaving most of Seal Bend too low to support healthy tidal marsh.

To raise the marsh elevation, our construction crew has been taking soil from the hillside next to Hester Phase I. The crew started in June and has already moved 100,000+ cubic yards of soil—more than 30 times the size of an Olympic swimming pool. First, they contained the site within an earthen berm to keep tidal water out of their work area. After grading the material to the correct elevation, they will cut new tidal channels based on the natural channel configuration obtained from historical images.

In previous phases of the project, we refined our understanding of how high to place the marsh in the tidal frame to ensure that it can withstand a meter of sea level rise. We learned that a firm layer of bay mud will help stabilize the edge of the marsh along the main channel, which is subject to the most tidal erosion. We’re also trying some new experiments in this phase:

PARTNERS PROTECTING ELKHORN SLOUGH

adding channel slurry to the new marsh that is rich in organics and likely contains a seed bank of marsh plant seeds; growing a half-acre of a nitrogen-fixing cover crop to promote pickleweed growth; growing pickleweed from seeds within the cover crop before the area is opened to the tides; and testing the idea that marsh plants may do better in topsoil.

Stay tuned for how these experiments go—we expect to have some early results next spring.

We’re honored to participate in Monterey County Gives, an annual year-end fundraiser hosted by the Community Foundation for Monterey County, MC Weekly, and the Monterey Peninsula Foundation. Between November 9 and December 31, a portion of every donation made through MC Gives! will be matched, increasing your impact.

ESF’s campaign this year is all about protecting water for wildlife and people. Every dollar raised will improve water quality by reducing erosion, restoring native vegetation, preventing groundwater overdraft, and preserving sensitive freshwater ponds.

None of this work would happen without the support of our community. Whether you’re a new member or wish to leverage your yearend gift with matching funds from our partners, please support our MC Gives! campaign today.

To raise the marsh at Seal Bend, our construction crew has already moved 100,000+ cubic yards of soil—more than 30 times the size of an Olympic swimming pool.

montereycountygives.com/elkhorn

We are also beginning to plan for the restoration of North Marsh—another area of the slough that was historically diked and drained, causing the land to subside. Restoration here will improve water circulation, water quality, wildlife habitats, and climate resilience while protecting public infrastructure.

There are some interesting challenges to tackle with this degraded marsh sandwiched between the railroad and Elkhorn Road, and public meetings are underway to gather information and input. If you’d like to participate, keep an eye out for postings on our website. n Cover: Reserve staff, interns, volunteers, and Moss Landing partners outplant oysters to Whistlestop Lagoon. Upper left: transporting soil at Hester Marsh. Photos by Elkhorn Slough Reserve.

Sea otter by Janet Kornblum.

NORTH MARSH

tidal exchange n 3

RECONNECTING OYSTERS & PEOPLE continued from cover stood in exactly this place, touching exactly this species.

Another threat to oysters comes from artificial tidal People and oysters have been intertwined for ages. restriction. About half the estuary remains behind water But have you ever seen a native oyster on the Pacific control structures, installed to hold back saltwater to coast? Most people haven’t, including many marine allow for farming or other land uses in former wetlands. biologists and coastal naturalists. That is because our Oysters are gone from these areas, where stagnant water iconic local bivalve has almost disappeared from West makes conditions unsuitable for oysters (and most other Coast estuaries. species). But we can bring oysters and health back.

Olympia oysters (Ostrea lurida) are the only oysters For example, Whistlestop Lagoon is one place that call this coast home, ranging from Baja California where oysters thrived in the past—it is ringed by Native to British Columbia. They American oyster processing were common “foundation shell piles. After water species” in many estuaries, quality there was impaired forming clusters and by a levee and narrow sometimes extensive beds culverts restricted tidal that provided structure in flow, few oysters survived. mudflats and important In 2014, the Reserve’s habitat for other species.

Tidal Wetland Program Now, you often only find restored a natural tidal single oysters; populations range to this area, and have declined so much now it is one of our most due to human alteration of successful oyster habitats. estuaries that few oyster beds The Reserve likewise hopes remain. to restore tidal exchange— At Elkhorn Slough, and suitable oyster oysters have been harvested habitat—to North Marsh

by Native Americans for in the coming years. more than 7000 years. They By gradually bringing were abundant as recently natural tidal exchange as the 1920s until they were back to the stagnant half overharvested by oystermen of Elkhorn Slough, we can from San Francisco Bay, who regain oysters and healthy collected many thousands in ecosystems throughout the a single week, according to estuary. Significant effort newspaper reports. Today, has also been invested in Dense baby oysters, stomachs full of algae (dark spots), on the day they are outplanted into the estuary. Photo by Elkhorn Slough Reserve. they are protected from buffering fields and slough harvest, but threats remain. waterways with conserved Only a few sites in the estuary contain oysters, and most lands and restored wetlands that trap and transform of these have just a few. excess nutrients from farm runoff. Collaboration with One challenge to Elkhorn oysters is deep organic local farmers is ongoing as we find ways to reduce inputs mud fueled by excess nutrients, primarily from farm to the slough and maintain viable farms. runoff. These nutrients grow massive algal mats in the While ecosystem-level restoration is the best way estuary, which decay into goopy organic mud with the to support oysters as well as species such as eelgrass, sea consistency of chocolate mousse. This is not natural and otters, and shorebirds, it is a slow process. We don’t have makes it difficult for oysters to live on mudflats without time to wait—oysters are at risk of local extinction right being smothered by this organic goop. now. I’ve monitored them since 2007, and in that time, 4 n tidal exchange

From left: Graduate student J. Harris (photo by S. McDermott) and Reserve staff members R. Jeppesen and K. Wasson (photo by Elkhorn Slough Reserve) deploy oysters in mudflats.

there have only been two years with good reproduction yielding a new cohort of young oysters the following year. Between 2012 and 2020, I found no juveniles at all, and I grew increasingly concerned that they could disappear from Elkhorn Slough on my watch.

So, to ensure that oysters survive in this estuary, we are giving the species a boost. Our goal is to increase the local population size from a few thousand individuals to at least one million. This is a modest goal—there are small sites in San Francisco Bay that host a million oysters. But it should be enough to help them hang on and return to successful reproduction, so that they’ll be poised to recolonize more extensive mudflats when nutrient reduction and tidal restoration bring back more highquality habitat.

Restoring oysters is not so different from bringing back native plants. Instead of growing native grasses and forbs in the greenhouse, we grow native oysters in a hatchery. While aquaculture— farming aquatic species—has been used to provide food for humans for more than a thousand years, it has only recently been incorporated into the conservation toolbox for coastal species. We are the first in California to pioneer restoration aquaculture of oysters.

Moss Landing Marine Laboratories serves as the

hatchery for our oysters, with guidance from California Sea Grant and funding from the California Ocean Protection Council, CDFW, and NOAA. First, local adult oysters are pampered with lots of algal food until they spawn. The larvae that are released are then fed more algae and provided places to settle. When the juvenile oysters are big enough, we outplant them into the estuary. To prevent them from getting buried in the muddy goop, we hang them from stakes.

Experimental restoration is an excellent way to rigorously determine which approaches are most effective. It also lends itself to academic study. Jacob Harris, a Moss Landing Marine Labs graduate student, is focusing his thesis on experiments he’s done with the Reserve. Together, we’ve learned that oysters in deeper water grow faster; that survival is much better if we leave the oysters in the hatchery until they are at least dime-sized; and that gaper clam shells seem to provide the best attachment surface for oysters to settle on and generate naturalistic clusters.

To support Olympia oyster restoration efforts up and down the Pacific coast, I helped found the Native Olympia Oyster Collaborative around 2015—

To ensure that oysters survive in Elkhorn Slough, we are giving the species a boost.

(continued on page 6) tidal exchange n 5

RECONNECTING OYSTERS & PEOPLE continued from page 5 a community of practice of oyster scientists, restoration practitioners, policy experts, funders, Native people, and shellfish growers. Over the years, we’ve learned from each other about the challenges oysters face and

backgrounds in restoration. Thanks to these events, there are now more than a hundred people who can say they’ve touched a native oyster in Elkhorn Slough.

Volunteers help to assemble the restoration stakes, and they count and measure the oysters when we first put them out in the estuary.

We’ve held two oyster restoration events in partnership with the Amah Mutsun Tribal Band, and one edible native food event where Tribal members tasted native oysters as well as locally harvested foods. This is just the start of efforts by the Reserve and the Foundation to serve as better allies to Native Americans reconnecting with coastal species they have stewarded sustainably for thousands of years.

My hope is that as a legacy of this work, there will be a time in the not-too-distant future when encountering native oysters on low tides is a common experience again at Elkhorn Slough. Together, we are working to restore not just the oyster, but the connection that has existed for millennia between people and this iconic bivalve. n

Thanks to these community events, there are now more than a hundred people who can say they’ve touched a native oyster in Elkhorn Slough. how we can better support them. We’ve written an article documenting oyster occurrences all along the coast, conducted a synthesis of restoration projects from Mexico to Canada, evaluated places where conservation aquaculture is most likely to benefit Olympia oysters (Elkhorn was one of them!), and much more.

All of our Elkhorn outplant events are communitybased, aimed at engaging people from diverse

! e t i s b e w w e n r u o t check ou elkhornslough.org

6 n tidal exchange

SLOUGH VIEW

Farewell to Slough Pioneers Mark Silberstein, Executive Director

It seems to me that generational change is only detectable in the statistical aggregate. It typically does not happen all at once. But over the past decade, we’ve said farewell to many of the pioneers of Elkhorn Slough conservation and welcomed the people who will continue to carry this work forward.

Lou Calcagno was a charter member of the Elkhorn Slough Foundation Board—along with John Warriner, Don Bussey, and Warren Church, with Anne Olsen as the attorney who drafted the incorporation papers. Lou and John opened the first ESF bank account in 1982, each depositing a check for $100. I joked with them both that they realized a serious return on investment.

Today, the Elkhorn Slough Foundation protects the largest tract of conservation land in the watershed, hosts strong and dynamic programs, and has enduring partnerships with the Reserve and other community organizations.

Lou passed away at the end of August at the age of 87 and was followed soon after by Carol, his wife and partner of 67 years. Lou was born and raised on Elkhorn

Lou Calcagno at Moon Glow Dairy, on the banks of Elkhorn Slough. Used with permission of the Monterey Herald.

Slough and lived his entire life overlooking the marshes and tides. He and Carol owned and managed Moon Glow Dairy and were deeply embedded in the life of North Monterey County. Lou served on the Monterey Planning Commission for 18 years before being elected as a County Supervisor, a position he held for 16 years.

Throughout his service, he and Carol ran the dairy together.

Lou loved Elkhorn Slough. He and Carol were honored with ESF’s Heritage Award, the highest honor the organization bestows, for their pioneering efforts and consistent support. Moon Glow Dairy is known as a birding hot spot, and Lou and Carol generously opened access to birders. For more than 45 years, Don Roberson has surveyed the site and tallied 296 species seen at Moon Glow over the years.

Lou and Carol were dedicated stewards of this place, and their legacy of service to Monterey County and Elkhorn Slough will endure. We owe them a debt of gratitude, we miss them, and we share our condolences with the family. n tidal exchange n 7

Elkhorn Slough Foundation P.O. Box 267 Moss Landing, CA 95039

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Calendars include holidays, moon phases, and daily tides— perfect for bird lovers, estuary explorers, and armchair travelers alike. They usually sell out, so get yours while supplies last.

store.elkhornslough.org Southern sea otter at home in the eelgrass, by John Blevins.

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