Imagine being your own boss, working with one of man’s most prized foods and getting paid good money to do so. Imagine riding to work in a boat and having an `office’ right on the water. Imagine spending your days breathing fresh air and your vacation lasting from December to May. Then take your imagination to the coast of Maine, for such is the life of a lobsterman.

But before you plunk down your money on a boat and traps (an investment that will run you more than $150,000), consider the down side of being a lobsterman.

Waking at 5 a.m. each morning and putting in 12-hour days, six days a week. Hauling 100-pound lobster traps out of the water and repeating the same back-breaking, monotonous motion 200 to 300 times a day. Setting sail in late November, when the wind chill factor brings the temperature down to zero and stormy seas buffet your boat like a cork. Having no automatic health benefits, paid vacations or even guaranteed income. Watching your hard-earned paycheck shrink with the vagaries of the marketplace.

One side of this life may seem like paradise; the other a nightmare. What is the life of a lobsterman really like? Let’s follow South Thomaston lobsterman David Cousens for a day to find out.

At 5:30 a.m., while most of us are still sleeping, Cousens awakes and grabs a cup of coffee for breakfast. His house faces the South Thomaston Harbor; his boat is docked almost in his backyard. He walks down to the dock where his stern man, Rick Feld, waits for him. Together, they row a small dinghy into the harbor where the “Alex and Andy” is moored. Named for his children, this is Cousens’ boat, a 36-foot Crowley with a white hull, rounded red bottom and a 325-horsepower Caterpillar engine. The 33-year-old lobsterman bought the boat as an empty hull and assembled it by himself.

The men stop for bait (pickled redfish) and fuel before setting off. It’s only a 10-minute ride to the first trap. (Cousens is lucky in this aspect. Lobstermen in Massachusetts or New Hampshire may commute as much as two hours each way to their traps.) Each lobsterman paints his buoys with different colors that are registered with the Division of Marine Fisheries. A lobsterman is required by law to display a float mounted on the cabin to make it easier for the warden to ascertain that he is pulling his traps, and his alone.

Cousens gaffs the buoy and feeds the warp (the line tied to the trap) through the block into the hauler. The block is a pully mounted on an inverted, L-shaped arm. A small motor hauls the traps to the surface. Cousens lifts the trap out of the water, swings it onto the shelf-like “wash rail” and opens the lid of the trap to remove the lobsters. Meanwhile, stern man Rick Feld removes the bait bag, fills it with fresh herring and puts it back into the trap. The trap is tossed back into the water. The entire operation is over in a matter of minutes.

The first pot yields a “short,” a “notcher” and two “keepers.” By Federal law, a lobster must measure at least 3 1/4 inches from the eyes to the end of the carapace in order to be kept. The shorts are thrown back in the water. Cousens’ record catch is 19 lobsters in one trap. The largest lobster he ever caught was a 15-pounder. He donated it to the Boston Aquarium.

Shorts aren’t the only lobster Cousens is obliged to throw back. Egg-bearing females are also illegal. Maine law requires lobstermen to cut a V-shaped notch in one of the right tail flippers. This indicates the lobster is a fertile female. Should she be caught by another lobsterman, even after the eggs have hatched, she’ll be returned to the ocean for breeding.

“There are six million pounds of notched lobsters on the Maine coast,” estimates Cousens. “At times, I catch a couple hundred a day. But I don’t mind, because saving the egg-bearing females means more lobster for everyone.”

The law also limits the maximum size a lobsterman may take to five pounds — even if the lobster is male. The reason is simple: “You’re not going to get a 7- or 8-pound female breeding with a 2-pound male,” Cousens explains.

The ritual continues: hauling and emptying the traps, changing the bait bags, discarding “shorts” and “eggers.” Cousens fishes more than 600 traps. Typically, he can handle 200 to 300 traps a day. The work day lasts until 5:30 p.m. or in David’s words, “until one of us gets sick of it.”

The work may be monotonous, but it certainly requires skill. At times Cousens sounds like a cowboy riding a herd. “To make a living at it, you’ve got to know where the lobster will be all year long,” he says. “The secret is to move your traps all the time.” In warm weather, lobsters come closer to shore; when the temperature drops, they head for deeper waters.

Once molted, the lobsters retreat from the shore. “We do a couple of hauls around the rocks, then follow the herd out to deeper waters, then come back in to catch another wave of shedders,” explains Cousens. The coldest months can have some of the best lobstering. “I’ve had some fantastic hauls in November,” says David, “averaging four to five pounds per trap.” The wholesale price changes weekly, fluctuating between $1.50 and $5.00 a pound.

Cousens is guardedly optimistic about the future of the Maine lobster industry. “We take 90 percent of the legal lobster in Maine,” he says, “but the 10 percent we miss are enough to keep the species going.”

I asked Cousens the best way to prepare lobster. His response was emphatic: “Boil ’em in 6 inches of sea water and serve ’em with melted butter.” According to Cousens, boiling produces a moister, more tender lobster than steaming or baking. (The latter dries out the meat, warns the lobsterman.) It’s also the most humane way to cook lobster. “The creature dies instantly,” says Cousens. “I haven’t heard a boiled lobster scream yet.”

Lobsters come in five sizes: “chickens” (1 pound), “quarters” (1 1/4 pounds), “selects” (1 1/2 to 2 1/2 pounds), “jumbos” (2 1/2 to 5 pounds). Figure on 1 to 1 1/2 pounds boiled lobster per person. Cousens maintains that the optimum size for lobster is 1 1/2 to 2 pounds. “Despite what’s written in cookbooks, jumbo lobster are tough,” he says.

“When buying lobster, make sure they’re alive and kicking,” he advises. Some people prefer female lobster. (There’s more meat in the tail and sometimes you’ll find a cache of the tasty orange roe.) To determine a lobster’s sex, examine the first set of swimmerettes (tiny legs) on the underbelly at the juncture of the tail and body. A female’s swimmerettes are soft and feathery, while a male’s are rigid.

But according to Cousens, the greatest delicacy of all is a “grape,” also known as a “jellyroll,” a lobster that has just shed its shell. “The meat is the sweetest right after the lobster molts,” says Cousens. “It’s easier to eat than a hard shell lobster and it also costs a lot less.”

If you do not have sea water, make salt water by adding 2 teaspoons salt to each quart of water. Boil 1-pound lobsters 8 to 10 minutes, 1 1/2-pounders 12 to 14 minutes, 2-pounders 15 to 18 minutes, and 2 1/2-pounders 19 to 24 minutes. Add 5 minutes’ boiling time for each additional pound. To tell if a lobster is cooked, lift up the carapace: The tomalley (the liver — the custardy green stuff at the back) should be firm but not hard.

Steven Raichlen is a Boston cooking school teacher and food writer.