Whirling disease found in Maryland stocked trout
A shipment of 8,000 rainbow trout from a private vendor to Maryland contained some fish with whirling disease, the Department of Natural Resources said.
The trout were used to stock several streams in Western Maryland that do not contain native trout. Biologists noticed on May 11 that some fish were acting oddly and they stopped stocking operations and began testing.
The fish were placed in the North Branch Delayed Harvest Area, Evitts Creek, Jennings Run and Sidling Hill Creek.
Whirling disease, found in 24 states, is harmless to humans but fatal to trout, especially rainbow trout. The parasite was first detected in the United States in the 1950s and was found in Maryland's North Branch of the Potomac River in 1995. Four years ago, the parasite was found at the Bear Creek hatchery in Western Maryland, forcing the state to close it and two other facilities and destroy all the trout.
Biologists say this outbreak can only be problematic if anglers move trout from one stream to another. Typically, stocked trout are either caught right away or die during the summer when water levels fall and temperatures rise.
DNR has declined to identify the vendor, but officials say they will not accept any additional trout from that source until testing is completed.
The discovery of whirling disease in privately raised trout is likely to increase the state's efforts to ramp up its own hatchery production. Maryland typically stocks more than 320,000 trout each year.
You can read more about whirling disease on the DNR website.