Take, for instance, a post Monday on the log by a man who identified himself as Nate Gillard, a recreational angler. The headline: "Snakehead off Surrats Road." The predatory fish, a threat to some ecosystems, had been caught in Prince George's County's Piscataway Creek. "Until I got him to shore, I couldn't believe what I caught, a 16" Snakehead!" Gillard wrote.