I was one hour on snorkel into an herbivore survey at the Kahekili Reef, West Maui, and an unknown critter came slithering across the coral. My camera was clipped to a utility belt and it took me a few seconds to swing it up to my face. I've learned I may have only one chance to capture a photo, so I took a quick photo from the surface before free diving onto a fish (attached). I was only halfway down in 15 feet of sea water when the critter dove head-first into the sand and quickly disappeared. Two photos -- from the surface, and a tail shot -- are the only evidence I have.
My heart was pounding because it looked like a sea snake, but only the Yellow Bellied Sea Snake is rarely seen in the coastal waters of the main Hawaiian Islands. The photos confirm it was not a sea snake, though friends who SCUBA in Palau and the Phillipines think the photo looks like a Laticauda colubrina - Yellow Lipped Sea Snake. My tail shot confirms a pointy ending, not a paddle-like tail, so it is not a sea snake. FishBase and Keoki & Yuko Stender's Marine Life Photography websites confirm it is the Leiuranus semicinctus - Saddled Snake Eel.
Kahekili Reef is an amazing low-profile reef in front of a West Maui development that we are trying to save by letting the fish and urchins "naturally" graze down the algae, and is now a Marine Protected Area.