"Blue-Lining"

Sounds like another obtuse colloquialism until you get the connection between tiny blue lines on a map and fly fishing small streams, where favorite spots can have names like “Nekkid Girl Pool.” George Grant and Clarence Moody fish some tiny water in western North Carolina. “On our way we passed the Davidson River and every pullover parking space was filled, ample motivation for Bluelining. ‘You know they like to call the Davidson “technical water?”‘ Moody said. ‘I think that’s just a polite way to say over-fished.'” On TriCities.com.