Maine officials have changed the rules so commercial fishermen no longer need a special license to harvest and sell green crabs. The Portland Press Herald reported that fishermen also will not need to report green crab harvests to the state, and lobstermen will be allowed to take the crabs as bycatch. Fishermen will also be able to harvest green crabs from the Sheepscot, Damariscotta, and Medomak rivers when they are closed for fishing other species of crabs between Dec. 1 and April 30. The new rules went into effect Sunday. The rule changes come at a time when government and fishermen are trying to rid Maine’s coastal waters of the invasive species, which preys on the state’s valuable shellfish population.