On Prince Edward Island in the Canadian Maritimes, many oyster farmers are seeing nearly 100% losses on their shellfish farms due to disease.
Down the Atlantic coast in New England and Mid-Atlantic states, farmers are carefully monitoring their shellfish crops to gauge the losses from a brutally cold and icy winter season.
North Carolina shellfish farmers, so far, have avoided any major mortality events in 2026. But the year is still young, and warming coastal waters can quickly become Petri dishes for diseases and viruses.
Dr. Ami Wilbur, who runs the hatchery, said so far this year North Carolina hasn’t seen any substantial mortality events. But, she added, it’s still early and mortalities seem to hit hardest mid-May through mid-June.
As mariculture, with a few fits and starts, continues to grow in coastal North Carolina and become an important economic engine for communities that often have few other growth avenues − especially if they aren’t on the beachfront — here are some of the natural and manmade hazards the state’s shellfish farmers often have to navigate.
Disease and pollution
North Carolina’s oysters haven’t had the easiest time in recent times. Overharvesting, destruction of oyster beds, and declining water quality as development encroaches on many pristine coastal areas have taken their toll over the decades.
Some researchers believe North Carolina has lost up to 90% of its historic oyster beds, and the lure of the state’s coast shows no signs of slowing down anytime soon. The population of the three-county Wilmington metro area, for example, has jumped from about 276,000 in 2000 to an estimated 494,000 in 2025. It is forecast to reach more than 651,000 by 2040.
But after more than 30 years of concerted efforts by the state, research institutions and environmental groups to help oysters and the farming industry worth more than $15 million annually, the mollusk prized for its salty taste and famed natural aphrodisiac properties is making a comeback in N.C. coastal waters.
Read More: On the North Carolina coast, a fight’s brewing over shellfish farms, moratoriums
Every year, however, holds the potential to throw up new challenges.
Having die-offs in shellfish farms is always a possibility farmers face, and large-scale events can be especially brutal and can cost watermen a season or more worth of product.
In the past few years, a series of mass-mortality events has devastated many oyster farms, killing 80% or more of the mollusks on some shellfish farms. Chris Matteo, who runs Chadwick Creek Oysters and Seed Nursery in Bayboro near New Bern and is president of the N.C. Shellfish Growers Association, said the die-offs appear to be concentrated in areas of high salinity.
In southern New Hanover County along the Intracoastal Waterway, a laboratory run by the University of North Carolina Wilmington is working to give shellfish farmers a helping hand.
Since 2011, the UNCW Shellfish Research Hatchery has been selectively breeding oysters, testing whether oysters from certain parts of the state − say Pamlico Sound or the Cape Fear River − offer better resilience and faster growth potential under a variety of environmental conditions.
Dr. Ami Wilbur, who runs the hatchery, said so far this year North Carolina hasn’t seen any substantial mortality events. But, she added, it’s still early and mortalities seem to hit hardest mid-May through mid-June.
Matteo echoed Wilbur’s sentiment, saying he had only heard of “very isolated occurrences” of mortality events so far in 2026.
But he added the searing years-long drought is of growing concern, since a lack of freshwater flowing into the state’s sounds and estuaries allows more saltwater to push further inland, potentially reaching levels that can harm shellfish.
As of May 7, the U.S. Drought Monitor showed all of North Carolina in drought, with nearly 61% of the state classified as in “extreme drought.” In Wilmington, the U.S. National Weather Service showed the Port City through May 11 had received 9 inches of rain in 2026. The normal amount is 15.7 inches.
Manmade challenges
Worrying about Mother Nature isn’t the only concern the state’s shellfish farmers face in some areas.
A temporary moratorium − adopted in 2019 and extended several times since − on new shellfish leases in New Hanover County was driven by complaints from waterfront homeowners and boat users about the density, view and rapid growth of shellfish farms in Masonboro and Myrtle Grove sounds.
That ban, along with a decades-long ban in Brunswick County, has seen the rapid growth of the industry in Topsail and Stump sounds in Pender County. But now Pender and Onslow county officials are pushing back, saying squeezing all of the leases into just a sliver of the coast isn’t fair.
According to the latest figures from the N.C. Division of Marine Fisheries, there are 525 active shellfish leases in North Carolina covering a little more than 2,500 acres of public trust waters. They include 85 lease footprints in Onslow County and 52 in Pender County. In contrast, there are six leases in New Hanover County − including the research operation at UNCW − and just one in Brunswick County.
Matteo said moratoriums don’t work to reduce user conflicts, but instead increase problems by concentrating shellfish farms in a smaller area and heaping additional pressures on an industry that benefits coastal communities, their economies and the environment thanks to the amazing water quality and habitat benefits of oyster reefs.
Shellfish farmers also sometimes have to face public concerns over the safety of their product, especially if eaten raw.
In December 2025, the U.S. Centers for Disease Control and Prevention (CDC) issued an alert about eating raw oysters due to a Salmonella outbreak that sickened dozens. The alert, widely reported, generated pushback from industry groups who said the vague and wide-ranging investigation pointed the finger for the outbreak at oysters − and potentially cost farmers millions in lost sales − even though the evidence of any connection, or association with a single region or producer, was flimsy at best.
Vibrio is another bacteria found in shellfish that often catches the public’s and media’s attention due to its potential to cause gastronomical and intestinal issues if the seafood, including oysters, is eaten raw.
Found in warm, brackish coastal waters, the organism floats around and accumulates in water-filtering species like oysters and clams. Thanks to climate change and warming water temperatures tied to the oceans absorbing more heat, the bacteria is appearing in more areas earlier and in greater concentrations.
According to the CDC, Vibrio causes an estimated 80,000 illnesses − and roughly 100 deaths − each year in the U.S., with about a dozen species of the bacteria pathogenic to humans.
But it is one specific type of the bacteria that sends chills down the back of health officials. Vibrio vulnificus is a flesh-eating bacterium that can lead to intensive care, surgical tissue removal or even amputation if not treated almost immediately.
Matteo said shellfish farmers follow strict protocols, backed up by monitoring by federal and state regulators, to prevent infected oysters from entering the food chain. He also noted that most Vibrio infections in people are caused by swimming in brackish waters with an open wound.
Reporting by Gareth McGrath, USA TODAY NETWORK / Wilmington StarNews
USA TODAY Network via Reuters Connect
