I'm not an expert on sea otter mating rituals but the actions displayed today definitely looked promising. There was flirting, what I think was scent marking, and at one point there was blatant submission with one otter lying on the ground waiting for a bit of attention.Doubtful - all the recent sea otters to come into Europe have been imported under strict contracts not to breed from them!
Looked like courtship to my untrained eye anyway...