The legendary wahoo is one of the fastest and most mysterious fish in the sea - and it serves as a worthy opponent to the most seasoned of fishermen.

Skipper Kevin Aderhold climbs down from the captain's chair and warns us that the forecast calls for rough seas. "Four to six feet. Everybody ready for a whuppin'? It's gonna be rough out there." He looks each of us in the eye. "I'm not kidding." Earl "Bayou" Dufrene, the boat's owner, shrugs. "Won't be the first, won't be the last."

The rest of us look at each other. Last week's trip was canceled because of weather. None of us got much sleep last night, tossing and turning with adrenaline. We're already here at the dock. As they say in the action movies, "Let's do this."

We leave the Venice Marina, chug out of the channel, and head south, past the shrimpers and tankers and Coast Guard boats, slipping out the back door of the Louisiana delta. Two hours south of New Orleans, the marshland tapers off to the end of the world. Ahead of us, there's nothing but the Gulf of Mexico.

Our charter boat is a twin-engine Glen Young Flybridge sportfisherman, 42 feet long and packed with high-end rods and reels. Its lockers are filled with fresh bait, frozen bait, and lures as long as your forearm. We're going to need it all, because we're after wahoo, the most difficult fish in the sea.

We could chase down a marlin and fight it for a few hours. Or we could drop anchor, toss out some chum, and wait for the tuna to show up. We could always do that. And to be honest, it would be much easier. But there's a special cult of anglers surrounding the wahoo, addicted to the folklore of a fish so mysterious not even scientists know much about it.

The wahoo, or Acanthocybium solandri, is a large mackerel found in tropical waters all over the world. Although its numbers are plentiful, it swims solo rather than in schools. Unlike similar fish, there is only one species of wahoo. It's never evolved into anything else.

Its snout measures half the length of its head, and its powerful jaws are lined with razor-sharp teeth. It's like a tube-shaped dinosaur. The dorsal fin folds down into a slot down its back, streamlining the fish into the ocean's fastest creature with gills. Wahoos have been clocked at 60 to 75 miles an hour. They routinely snap off regular monofilament fishing lines, and can bite an artificial lure in half.