Stereo recording with hydrophones

["Scott Fraser" scottbfraser]

Does anybody know if the human hearing system is capable of
directionality underwater? Given that the ear/brain evolved for use in
air I'm wondering if the HRTF even works in an environment of
profoundly different sound velocities. Without a standard then for
spaciousness or stereo width underwater can we say that one stereo
hydrophone system (widely spaced, near coincident, etc.) is more
accurate in its soundfield than any other, especially given that the
results will always be listened to in air?
Just pondering what stereo means when underwater.

Scott Fraser