Perhaps you mean `cover' ? We made a survey pass on a drop site in mid March, about 1 wk after ice out, marking almost no fish, dropped the 1st 8 "C" trees and came back in less than 40 minutes with more attractors and reorientated to drop the 2cnd set and those 1st 8 "C" trees were SWARMING with fish as if by magic...in short, NOT LONG !