POINT CLEAR, Ala. — Martha Crosby is an oyster gardener. During the growing season (May to November), her dock on Mobile Bay has cages filled with oyster shells and “spat,” or baby oysters. The oysters, once sufficiently mature, are taken to a reef in the bay to repopulate depleted reefs. Besides being an epicurean delight to some, oysters are important for filtering pollutants from the water and creating habitat for other bay creatures.

An Alabama Cooperative Extension Web page reads: “These beds serve as habitat for an estimated 300 species of vertebrates and invertebrates that help to form the food web of the estuarine ecosystem. By filtering as much as four gallons of water per hour, adult oysters help to remove phytoplankton from the estuarine waters they inhabit. This filtering activity improves the water quality in critical nursery areas where numerous fish and shellfish species undergo crucial developmental stages.”

Crosby has been interested in the health of the bay for years.

“We have watched it deteriorate,” she said. One of her earliest memories is of a man selling shelled oysters in a jar near their Point Clear home.

“They were absolutely delicious,” she recalled.

Those days are gone, but Crosby was intrigued when she heard of the program from friends.

“It sounded like a cool thing to do,” said Crosby. “It makes me feel grounded, and I am doing my bit to help. Anybody can do it.”

She got involved, and will be starting her fourth season of “gardening” soon. Gardening, besides allowing the cages to hang off the dock into the bay, also means hauling the cages out of the water once a week, measuring the oysters and ensuring that predators like crabs and oyster drills have not gotten into the cages. Crosby says it takes about an hour a week.

“The gardens do not interfere with the use of the dock,” said Phillip Waters, a specialist with the Alabama Cooperative Extension System and Mississippi-Alabama Sea Grant Consortium. He noted that the cages, which are about 18-24 inches long, are suspended between pilings and hang about 12 inches above the bay floor.

Crosby’s baskets, now cleaned and ready for spat, which should arrive in a few weeks, don’t weigh much. Crosby says they get heavier as the oysters grow, however. Sometimes, she said, it’s necessary to split up a cage of oysters so they are not too crowded and the cage is a liftable weight.

“I used to think of myself as a foster mom,” laughed Crosby. “First I was a surrogate mother, then a foster mother, then I became a gardener.”

Crosby explained, “The oysters have a higher survival rate” than those left on their own. When they are moved to reefs, they are bigger and better able to survive.”

But like most mothers, Crosby worries about her almost-grown children.

“I am concerned about my teenagers, the three previous generations,” she laughed.

According to a Los Angeles Times article, oysters produce the most offspring in the third through seventh year and can live up to 12 years.

People do not have to live along the waterfront in order to take in oyster farming. For a charge of $25, people can “adopt” a garden that produces an average of 250 oysters for planting on the restoration-enhancement sites, Crosby said.

“I see a lot of teachers and students on piers,” said Crosby, who added that school groups often make use of unused piers

“My son-in-law in Chicago is an oyster gardener in absentia,” said Crosby, smiling.

Last year’s Deepwater Horizon oil spill gave the oyster program pause. Crosby said that the oyster gardeners “got special cages” to grow their charges.

“If we had gotten oil we would not have been able to touch them,” explained Crosby, adding that the gardeners would have had to let the cages dry and the wet sand fall out.

There have been some “magic moments” as well, she said.

“My grandniece was here when she was 4 years old,” said Crosby. “We pulled up a cage, and thousands of little shrimp jumped out. It was like fireworks — an explosion of shrimp.”