@ Trap,
Yes It was Cousteau and Gagnan who invented the automatic demand regulator, the Aqualung or CG-45. Even Mike Nelson uses Aqualung/US Divers regulators in Sea Hunt pilots (there were two filmed). In the series he has switched to Voit (supplier of rubber diaphragms and hoses to US Divers), in exchange for the licensing of the Aqualung/US Divers regulators. It was television that allowed Mike Nelson to bring scuba and the underwater world to the average American's home and get a whole generation of people interested in diving. JY Cousteau while producing several oscar winning films about the underwater world, didn't start his US television series until 1966. So yes, Cousteau invented the sport, but Mike Nelson was its first mass promoter at least via the medium of television.