It's always a good idea to have your cell phone on board your boat. In an emergency, call 911. You will need to be able to describe where you are (the numbered buoys are a good starting point) and your boat identification number and description. Here are the numbers for other potential contacts.
NC Dept of Water Quality: (919) 791-4200 - Weekends & Emergencies call (800) 858-0368
Brunswick Co: Department of Environmental Quality (804) 527-5042 or 527-5173
Mecklenburg Co: Department of Environmental Quality (434) 582-6233 / 6236
Many boats have a maritime VHF radio on board. It is the recommended way to initiate emergency communication with U.S. Coast Guard, NC Wildlife Commission, VA Department of Game and Inland Fisheries, county law enforcement and Lake Gaston Water Safety Council equipped monitoring stations on the lake.