It pays dividends to be a diver with a small camera in a case waterproof to 50m, and not too bothered about all the paraphernalia of big cameras, multiple flash guns, exposures, white balance etc. etc. etc.
Chris Mandry of Ilfracombe and North Devon Sub Aqua Club uses this lightweight approach and obtains lovely pictures of marine life. As a staunch Coastwise member he knows that the best approach to this sort of talk is to get other members to do all the work, identifying and elaborating on the fauna and algae (a task which they really enjoy !). Chris wisely has the backup of confirmed IDs at hand.
Shown R from Top is a small selection of Chris' excellent images :-
Stafish Limb Maerthesterias glacialis
Furbelows holdfast Sacchorrhizo polypoides
Fried Egg or White Strip Anemone Actinothoe sphyrodeta
Sea Slug Egg Ribbon - species not known
Compass Jellfish Chrysaioia hysoscella
Candy Striped Flatworm Prostheceraeous vittatus
Jewel Anemone Corynactis viridis
Crawfish or Spiny Lobster Polynurus elephas (just before being returned to the water)