Living for days on end 63 feet beneath the waves is a near-ideal situation for researchers studying undersea life, biologist James Lindholm says. Yet sometimes the best-laid experiments can go awry. Lindholm once found himself tracking a large grouper that unexpectedly ate the accompanying smaller fish he had tagged electronically so he could follow the big one. "There's no substitute for being there," when studying sea creatures, Lindholm said Tuesday, and a prime way to do that is at the Aquarius undersea research lab in the Florida Keys.