Wizard interviews Kurt Busiek and Tad Williams on Aquaman. Thanks to Lucid for the links.
Justin Hartley interview:
Obviously a lot of the stuff was underwater. We would go out into the ocean. Everybody had wet suits on. I didn't realize how cold it gets without a wet suit. The water can be 72 degrees and after about ten minutes you're freezing. I would go down without a tank, without a wet suit, just wearing swim trunks and board shorts, and I would swim from one diver to another diver and share their air. I was down in the ocean for 20 minutes at a time without an air tank, breathing off of other people's tanks. I'm not afraid of water, but I had never done that before. When you're acting you don't want to have that fear in your mind because then you can't concentrate on your work.