I have never seen this before. Cormorants gather on a drifting giant kelp paddy on the open ocean where I saw them diving below then coming up in the kelp rubbing their backs on the seaweed. Another example of giant kelp being used to clean and/or remove parasites from an animal?
Phalocrocorax & Macrocystis pyrifera paddy 2014 10-09 SB Channel-001
A drifting paddy of giant kelp with a Heermann's gull on top and a California sea lion in the water. Giant kelp paddies like this are oasis for life on the open ocean.
Macrocystis pyrifera drifting paddy Zalophus & Larus heermanni 2014 09-09 SB Channel-x-014