Groton - Standing bare-chested in the Poquonnock River off Bluff Point State Park, the tops of his red swim trunks at the water line, Dave Bobbi was picking seaweed out of the basket of his clam rake when Al Potter approached from a narrow causeway.

"I'd like to check your permit," Potter, senior shellfish warden for the town, said late Tuesday morning about an hour past low tide, one of the prime hours for recreational clamming.

"Oh, certainly," said Bobbi, an East Hampton resident, as he walked back to shore to retrieve his paperwork, a nonresident day permit that cost $8.

"And can you hand me those clams?" Potter asked, pointing to a bag of the shellfish Bobbi had collected so far.

Looking through the half-dozen quahogs, Potter picked out the smallest one.

"This is a short one," he said, measuring it with his clam ring to show it didn't meet the 2-inch diameter minimum. "That happens quite often."

After tossing the small hardshell clam into the water, he checked Bobbi's permit and let him get back to the business of mining the mud for the makings of homemade chowder.

"No short ones, now," Potter told him.

Potter, 76, a retired Electric Boat welder, is one of the town's three part-time shellfish wardens, working a schedule that follows the tides to ensure clammers abide by the few rules of the otherwise simple, low-tech pleasure of harvesting edible bivalves.

Clad in khaki uniforms and badges, these clam cops ply their beats in shellfish beds from Mystic to Mumford Cove to Groton Long Point to the Poquonnock River areas off Bluff Point in a 14-foot motor boat, checking permits, clam sizes and total haul - clammers are limited to one peck per day - and collecting water samples monthly for public health testing.

Ed Martin, chairman of the town's Shellfish Commission, said the town sells 1,200 to 1,500 shellfish permits each year, at prices ranging from $5 for a one-day resident pass to $35 for a seasonal non-resident pass. Roughly 40 percent of the permits go to out-of-town residents, many of whom come to the Poquonnock River beds for easy access to an abundant clam crop from shore or small boat.

"I've seen times where there have been 70 or 80 clammers in this river," Potter said.

While summer is high season for clamming, the three wardens work year-round, helping the town's Shellfish Commission seed the shellfish beds with clams and oysters three times a year, changing signs to close beds after heavy rains, collecting clams when public health officials want to conduct meat tests and checking on the regulars and newcomers alike.

"You start out your interaction friendly and polite, and for that you get polite and friendly in return," said Bobby Allen, a retired Pfizer employee who's been one of the wardens for the past year, as he steered the boat toward a yellow vessel anchored off the Bushy Point Beach area of the park. "Most people are so used to seeing us, they keep their licenses on their hats or somewhere else handy."

Reaching the yellow boat, Allen greeted husband and wife Dennis and Rebecca Dickinson of Moosup and asked to check their permits. Reaching into his wallet, Dennis explained that his wife was just along for a relaxing day on the water.

"I told her I'm getting too old for this stuff, you've got to help me dig these things up, but she said, 'No way,'" he said, as Rebecca nibbled on a sandwich and nodded in agreement.

After Allen verified Dickinson's permit, he checked his clams, kept on ice in an empty mesh bag that once held 10 pounds of onions. Dickinson showed Allen the hose clamp he was using as a clam ring to make sure all the quahogs were legal size.

"We've got a cookout Saturday, so we're going to use these for chowder," Dickinson explained. "This'll make about 2 gallons, clear broth."

Satisfied, Allen returned the clams and turned his boat back to shore. Violators, he said, are few.

"If he didn't have a license, it would have been over the side with those clams," he said. "Usually, when you catch them red-handed, they throw them back right away."

Both Potter and Allen obviously enjoy having a part-time job that requires spending their working hours in beautiful coastal settings, away from the offices, labs and industrial workshops of Pfizer and Electric Boat where they made their careers. But the job is also an extension of lifelong avocation for both.

"I've dug a lot of clams in my lifetime," said Potter, who grew up in a house on the Mystic River. "When I bring them home, I scrub them down good, then you can store them flat in the refrigerator for seven or eight days. I make stuffed clams or chowder out of them, with salt pork and onions, the clear broth kind. I don't care for the creamy stuff. That's the way we grew up."

While most clammers use a long-handled rake with a basket attached, Allen prefers to "tread" for his quahogs, a technique he's taught his eight grandchildren.

"If you don't mind mud, you go in the water and when you feel a lump with your feet, it's a clam," he said. "Treading is kind of a lost art."

j.benson@theday.com