...apparently panicked at the surface when he and his equipment were entangled in kelp.
For people unfamiliar with San Diego diving, especially in the Point Loma area, getting tangled in kelp is not only common, I'd say it's downright inevitable if you dive around it.
Underwater, the kelp forests are stunning, some of my favorite dives. On the surface, it's a tangled mess. It's possible to get entangled beneath the surface as well as at the surface.
Kelp breaks easily when bent. Pulling it does nothing. Getting out of it is just a matter of removing a strand at a time, breaking when necessary. Like many scuba situations, the solution is to stop, think, breathe ...