Hmmm.... perhaps.....
Canon Beach is famous for it's rocks thought. When the tide goes out it leave little pools full of all kinds of edibles that birds go nuts over.
I don't know much about gull diet but aren't they mostly scavengers?
There were a bunch of jellyfish skeletons (?) along the coast but not more than usual for this time of year and that beach.
Here's a cool photo (not my own) of the rocks at Canon Beach: