Maryland's protectors of the Chesapeake Bay are watching out for a variety of toxic algae bloom that is thriving in Virginia rivers and potentially creeping northward.
A species known as Alexandrium monilatum, common to the warmer waters of the Gulf of Mexico, has been found in samples this summer taken from Virginia Beach, the James, York and Rappahannock rivers and on Virginia's portion of the Delmarva peninsula. One marine expert suspects it has even reached as far north as the Potomac River.
It emits a toxin that can be deadly to larval and spat oysters, larval fish and small crustaceans.
Bruce Michael, director of the Maryland Department of Natural Resources' assessment services, said state scientists are on guard for blooms of the algae.
"We haven't seen that particular bloom," he said. "It is confined to the Virginia portion of the Chesapeake Bay at this time. We are watching it closely."
Alexandrium was first detected in Virginia waters in 2007, though its first large bloom didn't occur until 2012.
It's not clear yet what health risks the algae poses. Virginia scientists are investigating whether it is to blame for reported die-offs of cownose rays and stingrays, or how it might be affecting oysters, according to the Daily Press.
There is no evidence so far of a health risk to humans from coming in contact with the algae or consuming seafood that has.
But the species is still worth looking out for in Maryland as the state continues efforts to reduce algae blooms in general, Michael said. Farm runoff, sewage leaks and other pollution containing nitrogen and phosphorus fertilizes the blooms, and when they die and decompose, they strip oxygen from the water, sometimes suffocating fish and shellfish.
Crews were out on state natural resources boats as recently as last week and did not find any signs of Alexandrium, even though hot and dry conditions have been conducive to blossoming algae since August, he said.
Tribune Newspapers contributed to this report.