Landuse=aquaculture vs. seamark:type=marine_farm

I just added some aquaculture sites around Iceland and I was unsure about whether to tag them with landuse=aquaculture or seamark:type=marine_farm. I tagged them with both, but that seems like duplication of information to me.

I’m talking about sites like this:

How should these be tagged?

Aquaculture can occur on “land”, both in quite isolated small ponds, and tanks. seamark:type= won’t be used for those. Therefore =marine_farm might be considered a subset of =aquaculture in theory. Double-tagging is fine.