For the jetties you want something like a grapple hook set. A Mighty Mite, which is a good one but you can also make one with rebar and concrete. The reason is that you want something that will bend out if need be. Many, many anchors have been lost at the jetties. If you need to tug your anchor out of the rocks with the outboard the tines of the mighty mite or rebar anchor will bend.. other anchors will slip inside the rocks and not budge.. bye bye to that anchor. Once you get your anchor back just rebend it back into place and you're good to go.

I'm not affiliated with Mighty Mite non any rebar companies. It's the only anchor for that specific use. .. Now if you are anchoring on the sand on the outside of the jetty.. then yes, any Danforth anchor will do.