I'm not sure. I found this, which seems to make it likely:
The faces of both sexes often appear light colored. This is not coloration at all, but is an encrustation that comes from their curious habit of sneezing salt. This is part of the unique adaptions that have evolved that allow these descendents of terrestrial ancestors to live in salt water. A gland connected to the notrils removes salt from the body, which is then expelled by "sneezing".