GEORGETOWN — Like many Maine fishermen, Bryan Kelley faces a dilemma as he looks to diversify beyond the lobster that account for the bulk of his catch. To target pollock, which are relatively common in the Gulf of Maine, he has to fish in the same areas frequented by cod, a type of groundfish protected through strict federal catch limits. “We literally have to stay away from the codfish,” Kelley said while standing on his 40-foot boat moored in the Five Islands harbor of Georgetown.