What you'll learn on a first-time outing with Bobby Twitchell: techniques for holding your breath far, far longer than you thought possible (rhythmic breathing and visualization are key); how to identify tasty fish and those that must be avoided; how to get DEEP while conserving precious energy and oxygen; and of course how to shoot a speargun :-). I was able to reach 40+ feet with Bobby's instruction, deeper than the 25 feet that I had thought was respectable. You'll also learn how to descend from the surface in a "quiet" manner that avoids splashing and spooking the fish. Entry is from the beach or rocks, so no worries about boats/sea sickness. Bobby explains that while it's easy to spear any old reef fish, that approach leads to a reef depleted of the colorful creatures that draw us there in the first place. Thus his focus mostly on the roi, or grouper, a species that has wreaked havoc on native fish populations. Go with a pro: Bobby was born and raised on Maui and knows choice spots for freediving and fishing; he's reached almost 200 feet depth (!) with just mask and fins. His manner with clients was professional, polite and educational (he's a former school teacher).