Things you don't usually see

I recently read a surfing book that had some pictures of "wormholes" behind a wave that had been taken on a reef in Tahiti. I'd also seen a shot a while ago that Bluesnapper had taken at a northern beach which had these same things adorning the back of the wave.

I was surprised to see the same thing in some photos I took last weekend.

How do they form? Are they full of negative ions? Are they more common than I think they may be?

Anyway, whatever the answer, I like them. They are something I rarely see.