And let's face it- becomming a commercial diver is a tough row to hoe these days, regardless of where you get your training. Competition is fierce, pay is low to start and this ain't the best economy for construction work of any kind. I may just own a small hull cleaning business, but I get calls and e-mails from hard hat divers looking for work all the time.
There's work in the Oil Industry if your experienced and qualified. A well-qualified Diver can make $1000 a day, $1500 for a Supervisor, $2500 U.S. per day as a Diving Superintendent and $3000 per day as a Diving Consultant. It takes years to get to the top, but it can be done.
I'd guess that the calls you're receiving are from on-shore air divers starting out in the industry without full-time positions.