A ring, well spotted fellas.
I wonder if these sites may fit-in with Graeme Cs recent researches into the North West American Indian association between fishing and rock art?

Thanks for posting the Van Hoek picture of Barraglom http://www.themodernantiquarian.com/post/47283.
For various reasons I didn't take any photos at the time and when I returned the following day the tide had covered the rocks.