Why don't I post more mantas? I dunno, we see a lot of them.
These are great fun to photograph. Sometimes they'll tag along or do fly overs for the duration of the dive. If they let you come close, which happens frequently, you'll want your wide angle - this one had a wingspan of about 3 meters, and they can get much larger. If you shoot from below, you can identify individuals by the unique spot pattern. More then once I thought I've been shooting the same manta during a dive, only to realize upon reviewing the images that 2 or 3 had made passes at me...
According to the Manta Pacific Research Foundation: www.mantapacific.org/mantapacific/identification/index.html as of January 2011 there are about 175 idenitfied mantas in West Hawaii. The Kona population does not co-mingle with the mantas on Ohahu or Maui.
A friend and I dived Makalawena a few years back, and we ID'd a juvenile. Cute little thing with a 4 foot wingspan, so we thought there was a good chance no one had seen it before. Kenny had the camera and got the shot, and named it after his wife, Margo, #114. Cool stuff.