Unusual circumstances- during storms, at night in the open sea, in a tuna trap or purse seine. O.K. Quality counts more than quantity. Marine life- unusual creatures, remarkable behavior, exceptional concentrations, spawning, feeding, defense mechanisms, mimicry, camouflage, commensalism, juveniles and adults, males and females, mass schooling. Even the anthropologists haven t explored much of this. Don t forget the setting.
Diving often involves exotic locations.
Tell and show us something about the setting of your story, both above and underwater. Try to convey the look, feel, sound, and smell of the place, whatever is special or interesting. Perhaps it s the luminous quality of the water, or the scent of copra, or the muted cries of seabirds returning at dusk. It s all part of what diving is really about. P.S. aerial views can be great also.