Virginia oyster farmer Alex Lambert lost nearly his entire harvest after an unusual and severe algal bloom struck his farm on the Eastern Shore in mid-September. Lambert received initial warning on September 17 from a neighboring grower about discolored water in nearby creeks suspected to be harmful to marine life. By the following day, the situation had drastically worsened, with stagnant, brown water and dead fish visible around the farm.

Despite efforts to protect approximately 500,000 smaller oysters by moving them closer to shore, many of these oysters, which were initially closed and appeared healthy, began to gape open and die within two days. Larger oysters soon followed, leaving Lambert’s operation with a near-total mortality rate across his 4,000 oyster baskets. The financial loss is estimated at around $400,000, with only about 10 percent of the basket stock salvaged.

According to Lambert, this level of loss is unprecedented on his farm, and the dense concentration of the bloom along with its stationary presence contributed to its lethality. Nearby farms along Hungars Creek reported surviving the bloom, underscoring the localized severity of the event.

Scientists are still working to understand the precise cause of the bloom, which involved a shift from an initially harmless algal species, Margalefidinium polykrikoides ("Marge"), to the toxic Alexandrium monilatum ("Alex"). Margaret Mulholland, a professor at Old Dominion University’s Department of Ocean & Earth Sciences, noted that while such blooms are generally linked to nutrient pollution and warm water temperatures, the exact triggers remain unclear and could take decades to fully identify.

The bloom’s movement toward the Eastern Shore was unusual, likely driven by an atypical meteorological event resulting in an uncommon transport of algae-laden waters in the Chesapeake Bay. Hamish Small, assistant research professor at William & Mary and the Virginia Institute of Marine Science, highlighted that large blooms of "Alex" have been recorded only infrequently in the bay, with the last major occurrence in 2017 and none previously reaching the Eastern Shore area where Lambert’s farm is located.

Last month’s nor’easter is believed to have helped dissipate the bloom. However, concern persists that Alexandrium monilatum may have settled into sediments in the affected creeks, forming cysts capable of future dispersal and potential reoccurrence.

Lambert Shellfish is now focused on rebuilding, aiming to plant new oyster seed before winter halts growth. Testing with a small batch of seed showed promising survival, and re-seeding began earlier this month. Lambert emphasized the need for improved communication and protocols within Virginia’s aquaculture industry to provide timely warnings of bloom threats. He noted that earlier alerts could have allowed growers to salvage their stock before the bloom’s impact.

“We need to have a protocol,” Lambert said. “We could have saved all of our seed if we had been given two days.”