No, I think they are sea sponges. It is more a burning along any part of the body that touches the bottom of the ocean and although the burning is INTENSE during that evening, it always clears up by morning. Kind of strange but definitely not sea lice...
It appears that sea lice float and what we were experiencing only occurred after skin made contact with the mud at the skyway and at east beach. It also did not cause a rash like the one in the picture but rather just a redness of the skin for a few hours...
http://www.nativeplanet.org/health/dangeroussealife.htm