ANYONE WHO'S EVER GONE CRABBING has a theory on what attracts the biggest and best. If they are advocates of the chicken-neck method, of course, they have plenty of idle time under a hot sun to work on the theory. There is a better way.

Baited trotline: It gets the big ones everytime.

Admittedly, it's not for everyone. Not every crabber will want to tie slices of salted eel every five feet along a 150-yard line. And not every crab-eater wants to incur the expense of a boat (though small) with a motor. But if you're not too squeamish to handle eel, or you already have a motorboat, there's nothing more exciting than trolling the line and scooping up the best hardshells the Chesapeake Bay and local rivers have to offer.

"I don't think I'd ever go back to chicken-necking," says Brenda Hardesty, of Budds Creek, Maryland, speaking of the age-old practice of tying a neck to a string and then netting the nibblers. "It takes you almost all day long to catch a dozen. With trotline you can catch about a bushel in nearly an hour, come home, cook 'em, sit back and enjoy them."

Brenda's husband, John Hardesty, is something of a trotline expert. When the season is in full swing, Hardesty rises before dawn as often as three times a week and slips his 16-foot runabout onto the nearby Wicomico River.

As the sun rises, a morning breeze blows the fog across the rolling southern Maryland hills, exposing the antebellum mansions that dot the surrounding corn and tobacco fields. The scene could be mistaken for a French impressionist landscape as Hardesty guides his craft to a spot on the river that has treated him well, and there into the brackish saltwater drops a lightweight cinderblock with his trotline fastened to it. Although he can't see them, Hardesty is able to hear other crabmen who have already staked out their spots not far away. They are not to be disturbed; it's crabber's code.

Soon the line is stretched out along the river bottom, fat blue claws picking at their demise. Hardesty swings his boat around and returns to the float at the beginning of the line. He hooks the line and places it between two metal pegs, driven into a wooden plank stretched across the bow. The homemade device guides the line as the boat slowly putts along, lifting the trotline out of the water. The crabs are so preoccupied with eating that they are easily nabbed with a long-handled metal net.

"Don't use anything but a metal one," says Hardesty, "or else they'll get 'em tangled and you'll miss the next batch."

As the boat moves along the line, huge crabs, often one on top of another, come rising out of the water. The metal net meets them at the surface and drops them into a basket in the center of the deck. After maybe a dozen "doublers" are thus snatched, one mate on board suggests that possibly the large male crabs have more on their minds than just breakfast. The others on board snicker. It grows into belly laughter and the boat, belly heavy already, begins to rock. Hardesty suggests the guests return to the balanced seating arrangement and all is well for the next four trips down the trotline.

During which several bushel baskets are filled to the top with "Jimmies," or No. 1s: the biggest crabs.

Hardesty doesn't claim any regional pride for the size of crabs in his stretch of the Wicomico. With trotlines, he says, "You can go anywhere and catch the big ones."

Not everybody is as thrilled with trotline crabbing.

"It's a pretty messy thing to do, the whole idea of bait and rebait," says Chris Judy of the Maryland Department of Natural Resources. "After a couple days, the eel falls apart in your hands. It's pretty messy and smelly."

Judy says he's crabbed with a trotline only once and that "if it wasn't for the messiness of the bait, I'd probably do it again." TOWING THE LINE

A trotline is made of medium-weight cord and costs roughly $50. (Hardesty says if the line is taken care of and hung up to dry at the end of the season, there's no reason it won't last 10 years.) The line is anchored at each end by medium-sized weights -- Hardesty uses a couple of 8- by 16-inch cinderblocks. About 15 feet from either end are floating markers. (Plastic gallon jugs are perfect.) From there, 12-foot lengths of metal chain are used to add weight to the line. The best results are had in depths of six to 15 feet when the tide is changing; the movement stirs the critters out of the grass and into a hungry state.

Hardesty says he spends about $1.25 a pound at the beginning of the season for about 30 pounds of salted eel packed in brine. Using slipknots every 5 1/2 feet or so, he baits the line in about an hour. A novice, he figures, would need about three hours and should be careful to avoid blisters. Depending on how hungry the crabs are, Hardesty baits his line about once every three outings. He carries an extra bushel basket for the line and neatly packs the trotline into the basket and puts it into a large freezer between outings.