The Sackett Bank sits in the Gulf about 22 miles southwest from the tip of the Louisiana delta. Imperceptible to the naked eye, it's actually a massive underwater dome, about 200 feet below the surface, and surrounded by water twice as deep. Currents around the mound create natural upwellings that attract small fish, which in turn bring top pelagic predators like tuna and wahoo. Anglers call this area the Midnight Lump. It's about seven square kilometers of excellent fishing.

We approach the Lump, where several boats are already bobbing on the surface. If we were after tuna, we'd stop here, too, but the wahoo are rumored to be farther out. Captain Kevin speeds us on through the Midnight Lump.

Oil platforms start to pop up in every direction on the horizon. Since the late 1940s, oil companies have erected around 3,000 rigs off the coasts of Texas and Louisiana, milking the precious fuel from the ocean floor. To catch fish in the Gulf, you go out to the rigs. Smaller fish like to hang around the pilings, to hide from the bigger fish - for instance, a hungry wahoo.

Kevin slows the boat down and approaches a rig. We put out three lines and begin slowly circling the platform. "Sometimes they're smarter than you," Earl says, lighting a cigarette. "The bigger ones are harder; they've been around a few times. You have to make 'em wanna bite."

A couple of workers in hard hats watch us from the catwalks. I ask Earl how you can tell it's a wahoo on the bait. "You know what you got," he smiles. "That line goes across the water at 40 miles an hour. It's singin'.?"

Earl grew up on the bayou and has been fishing nearly all of his 55 years. His charter business is only a little over a year old, but he's already thinking of getting another boat. Like every other fisherman in Louisiana, he eats a lot of fish. But he can't stand sushi, can't bear the thought of eating raw tuna. On the other hand, Earl admits he loves to eat raw shrimp, heads and all, with "a little salt, pepper, Tabasco."

We speed off to another rig and start circling again, trailing three lines at a slow speed. No fish here either. We head out farther and reach what's called the rip, where the blue ocean water meets the green water from the Gulf. It's a dramatic, visible line in the ocean, blue on one side, green on the other, divided by a wall of vegetation extending, often, all the way to the sea bottom.