Except as hereinafter provided and unless otherwise specified by regulation, no person shall take any oysters, bay quahaugs, or soft-shell clams from the waters of this state by dredges, rakes, or other apparatus operated by mechanical power or hauled by power boats. No licensed person shall cast, haul, or have overboard any dredges while fishing for oysters, bay quahaugs, or soft-shell clams from the free and common fisheries of this state, nor shall any licensed boat be used for fishing oysters, soft-shell clams, or bay quahaugs with dredges, except as provided in this section; provided, that any person having a license issued under this title for the taking of scallops may use a dredge or dredges, not exceeding six (6) in number nor exceeding twenty-eight inches (28?) each in width, for that purpose; provided further, that the licensee shall immediately return all oysters, soft-shell clams, or bay quahaugs caught by the licensee to the waters from which they were taken. Any licensed boat may be used in dredging for mussels by the licensee of that boat, the licensee having first obtained a permit from the director of environmental management allowing the licensee so to do; provided, the licensee, while dredging for mussels under the permit granted the licensee by the director, shall immediately return all oysters, scallops, or bay quahaugs caught by the licensee to the waters from which they were taken. The fact of any licensed person being found with oysters, scallops, or bay quahaugs in their possession while dredging for mussels shall be prima facie evidence that person was fishing in violation of the provisions of this chapter and shall be subject to the penalties and fines imposed by this chapter. Any resident dredging for surf clams or skimmers shall not be in violation of this section if that dredging is done southerly of the coastline of Little Compton, southerly of a line extending from Church point, in the town of Little Compton, to Flint point on Aquidneck Island, southerly of the coastline of Aquidneck Island, southerly of a line extending from Castle Hill point on Aquidneck Island, to southwest point of Conanicut Island to Bonnet point, Narragansett, easterly of the coastline of the town of Narragansett, southerly of the coastline of the towns of Narragansett, South Kingstown, and Charlestown, and westerly to the Connecticut line. For the purpose of this section, “coastline” refers to the land facing the open sea.