Can Oyster Reef Restoration Across the US Impact What We Eat?

Some believe the tragedy lies in the disappearance of a tasty local mollusk from our tables. But it’s actually a lot more significant than mere human gustatory lacking. When this keystone species all but disappeared from the Hudson River — and also dwindled in Long Island’s Great South Bay, and the Delaware and Chesapeake Bays, and in estuaries throughout the South, in the San Francisco Bay and elsewhere on the West Coast — it took with it habitat and food resources for numerous species of fish, insects, birds, other animals, and plants. It eradicated critical ecosystem benefits; as has been widely touted, one oyster can filter out sediment and chemicals like nitrogen from 50 gallons of water a day. It destroyed thousands of miles of reef that protected coasts from storm surge, flooding, and erosion.

A parallel tale has begun to be told over the past decade-plus, though, ever since oyster reef restoration was begun in New York Harbor by non-profit Billion Oyster Project (BOP) and loudly called attention to what these mollusks can do when reintroduced to their natural environment. In a lot of people’s minds, this work must surely herald the return of the region’s native eastern oysters — Crassotrea virginica — to neighborhood fish markets. And in fact, in the state of Louisiana, oyster reef restoration efforts do have the primary purpose of bolstering that state’s oyster fishery.

But the purpose of BOP and most other oyster reef-building projects isn’t to feed us — at least not directly. Rather, they seek to regain those ecosystem benefits we’ve been losing for over 100 years and to make our coastlines more resilient.

Nevertheless, these environmental efforts still provide significant benefits to fishing and fisheries — in short, the stuff we eat. “When shellfish are planted and are able to reproduce and broadcast their larvae, that has the direct impact of increasing different fish populations, as well as improving waters so that more shellfish can survive,” says David Bushek. He’s director of the Haskin Shellfish Research Laboratory at Rutgers University in New Jersey. “Also, [oyster reef] habitat is used by other organisms as a nursery or place to forage, which increases those populations, including fish that [humans] go after.”

In short, when oysters win, so do a lot of other species, including ours, in more ways than one.

Louisiana’s Edible Reef

Two thousand miles south and east of San Francisco, Louisiana’s coastal marshes encompass the largest commercial oyster fishery in the country, providing $317 million worth of total economic impact to the state a year, according to Louisiana Seafood. Crassotrea virginica is the native species here, just as on the East Coast.

“It’s not just that oysters are out there performing ecosystem services, which is wonderful,” says Louisiana Department of Wildlife & Fisheries assistant secretary Patrick Banks, referencing the way reef adds “habitat value” to associated species and filters water to minimize algal blooms. “But they’re a very important part of our society and our culture.”

Banks says that reef habitat improvement and rehabilitation projects, using cultch, or shell, have been ongoing on public grounds since 1917. “For many decades, this method was very successful, but in the last decade and a half they haven’t been as successful as they once were,” he says. As a result, oystermen and women have been forced to transfer about 95 percent of their production to private grounds, away from what Banks calls “impacted areas.”

The cause of said impacts: a suite of ecological disasters, one on the heels of the other, that has made recovery of the fishery next to impossible.

“It started in 2005 with Hurricane Katrina — that was a tremendous impact to the extensive reefs on public grounds East of the Mississippi River,” says Banks. “Those started to come back, then hurricanes Gustave and Ike came in 2008. Then we had the BP oil spill 2010. We had a flood event in 2011 which put a lot freshwater over these reefs.” (As Food Safety News explains, oysters die when their saltwater balances are thrown off by too much river water; says Banks, “To be very simplistic, their cells burst.”)

On the heels of all that have come four years of major flooding events, including 2019’s historic flooding of the Mississippi River. “Once reefs are heavily impacted, it takes three to four years to come back,” says Banks. “But these episodic events are happening every three to four years, so they can’t get a foothold. It’s been a very difficult place to be an oyster, to be honest.”

Louisiana’s oyster reef restoration efforts have been focused on those public grounds, which historically comprised 1.7 million water bottom acres. There’s been some new reef built and old reef restored in these areas, but also some expansion into other locales. “We’re trying our best to move away from known freshwater sources like the Bonnet Carré Spillway and into areas that are more stable these days in terms of salinity,” Banks says. The goal: to rebuild to a production level that supports an average of 20 oysters per square meter.

Unlike in New York and San Francisco, where oyster shell is the primary building medium for reef, Louisiana, which exports almost 60 percent of its oyster harvest, has a shell deficit. So, the state has turned to limestone rock and crushed concrete; since these materials are heavy, siting for new reef is extra-challenging due to muddy water bottoms. Banks says that decreased oyster numbers means they’ve also had to begin seeding reefs with spat —  an expensive prospect that’s will be at least partially offset by federal disaster aid monies.

According to The Nature Conservancy, 170 marine species have been counted in oyster reefs in the northern Gulf of Mexico, including several that are almost as tied up as oysters in Louisiana’s economy and identity. Says Banks, “We’ve found shrimp feeding and living around an oyster reef; blue crab is a big industry here and they love to live around oyster reefs. Speckled trout and red drum live around oyster reefs — talk to any recreational fisherman and he’ll tell you he prefers to fish over oyster reef any day of the week.”

While none of these species are in conservation trouble, “In Louisiana, oyster reefs are just as important habitats as marshes are,” Banks says. “A lot folks feel like if you do what’s good for oysters, you do what’s good for estuaries. As an oyster biologist, I believe that.”

Top photo by Stephanie Kiriakopolis.