When you come across a distinct color change offshore, you’ll have different species of fish meeting there. There are different kinds of bait fish and predatory fish gathering there where temperature, current or color change holds those fish. It becomes a two-lane highway where predatory fish are looking for something to eat. If you’re fishing for those cobalt blue predators like blue marlin, yellowfin or wahoo, you want to troll just off the line between the two color changes.