Though mid-August, it remained mostly quiet on the Chesapeake’s pfiesteria front.

On Aug. 19, a Maryland Department of Natural Resources crew found lesions on 89 of 535 menhaden caught in Shiles Creek in Wicomico County Creek, where biologists had found signs of toxic pfiesteria earlier this month.

Health officials did not close the creek because there is no evidence of a major pfiesteria outbreak. “It’s certainly not enough to trigger a closure, but it is greater than we’d like to see and we’d like to keep an eye on it,” said DNR spokesman John Surrick.

In Virginia, meanwhile, researchers found fish in the Great Wicomico River that appeared to have been attacked by Pfiesteria piscicida. Virginia Department of Environmental Quality spokesman Bill Hayden said that of 361 menhaden taken from the river in early August, 37 — or slightly more than 10 percent — had sores of the kind associated with the organism. That was below the 20 percent threshold that the state’s pfiesteria task force set earlier this year as the trigger for action.

North Carolina, where the organism was originally discovered several years ago, has not been so lucky. Pfiesteria is estimated to have killed about 500,000 fish, many of them Atlantic menhaden, along a seven-mile stretch of the state’s lower Neuse River in late July and early August.

A pfiesteria outbreak in three Chesapeake Bay tributaries on the Eastern Shore last year devastated Virginia and Maryland’s important seafood markets and triggered legislation aimed at curbing nutrient runoff — which is thought to contribute to pfiesteria outbreaks — in Maryland. In that event, about 20,000 fish were killed and Maryland and Virginia both closed portions of the Pocomoke River, which they share on the Eastern Shore.