Spinner sharks, apparently a larger version of the black tip shark, are the most spectacular of the sharks that hunt the flats. The other sharks won't disappoint, though, for in shallow water they all, with the exception of the nurse shark, fight like demons, just with different intent. Indeed, the character difference between the sharks adds excitement to the mix.

The black tip, probably the most common flats shark during most seasons, are just about as lightening fast as the spinner, but not so wild in the air. Some black tips don't jump. Those that do make headlong leaps, head twisting, turning, shaking, as the body continues to swim through the air. Most black tips weigh in at 50 to 80 pounds. On light tackle, they're one of the greatest sportfish in the world.

Lemons, sleek sharks, may weigh 200 or more, come in fast and hot, fight long and hard, making long runs, but usually stay subsurface. They, too, are one of the most common sharks of the flats in the Florida Keys and are present year long.

Bull sharks are brutes that may surpass 500 pounds, though most bulls on flats in the Keys seem to weigh up to about 250. The best fishing for them is during winter, from January through March. They swim steadily and strongly, never really exerting themselves in an instant, like the spinner shark, and therefore fight long and hard.

Very hard. We once stayed right on top of one, that is, kept the boat almost over a bull after it ran off the flat, sounding into water 20 feet deep, and fought the fish for an hour with intense pressure from 50-pound standup tackle, before the captain said, Hang on! And we ran full speed a hundred yards ahead of the fish, kept moving forward as we tightened up and then began fighting the fish forward. The fish planed toward the surface and once there we were able to touch leader and pull the hook on this 400 pound fish. Without this trickery, I believe it would have taken another hour to land this fish.

It's possible to encounter a monster on the flats, one of the Big Moes that swim the waters from Key West up to Marathon and beyond. Occasionally, someone will see a 20-foot hammerhead. I've had one 12 feet long -- a fish with a dorsal fin that stuck almost two feet out of the water -- eat a 100-pound tarpon at boatside -- blood, scales, and gore.

Most of the hammerheads I've seen on the flats have been the most wary sharks of all, almost impossible to tempt. Then one did the opposite one day, sneaking in -- they're extremely fast -- and grabbing the 'cuda hanging on the tether line from the bow. Poking the fish with my rod tip was the wrong thing to do, for it went ballistic and, jaws snapping, almost came into the boat. That one measured about 7 feet, a common hammerhead on the flats.

The water is too warm for cold-water sharks like the Mako to wander so shallow. I also haven't encountered tigers, although Keys guides suggest they swim shallow shoals during midwinter, just before spawning. Big tigers are built like battle cruisers, but apparently run much faster and fight much harder and longer than even bull sharks.

So I tell you this cast of characters are of substantial substance and character, fish fitting of the environment in which they swim, which is spectacular, one of the greatest sportfishing venues of the world. I could attempt to tell you, but go see for yourself.

A fine angler named Romney once said that, "Fishing's purpose isn't to kill time, but to make time live; not to help the individual make time, but to make time serve him . . . " Shark time is some of the best time of all, an exciting diversion from our common freshwater friends.

SHOULD YOU DECIDE TO GO . . .

The Marquesas lie some 20 miles due west of Key West, at the western end of the 120 miles of continuing keys that run from Key Largo to Key West. Two of the best captains in the area are David Esquinaldo (305-294-5670) and Nick Malinovsky (305-745-2326). Depending on the season, sharks may inhabit shallow shoals all along the Gulf and Atlantic coasts.