Conchs -- known for their shells and their edibility -- get a helping hand

Long before tourists in the Caribbean Basin discovered conch chowder and fritters, conch - a high-protein marine mollusk - was a dietary staple of pre-Columbian Indians on the islands.

But today, increased consumer demand, heavy fishing, and poor conservation have depleted natural conch populations, jeopardizing the basin's second-largest fisheries export (after spiny lobster).

That's why conch hatcheries could play an important role in replenishing the conch population in the Caribbean Basin and helping the natives who depend on conch for a livelihood. One such hatchery, on the remote Turks and Caicos Islands, is raising queen conch - the meatiest, most marketable species.

The hatchery, run by the nonprofit foundation PRIDE (Protection of the Reefs and Islands from Degradation and Exploitation), is situated southeast of the Bahamas on Pine Cay, one of 40-odd tiny islands that comprise the Turks and Caicos Islands.

Mariculturist Megan Davis, assisted by PRIDE workers and a Peace Corps biologist, has fenced off an underwater ''egg farm'' on the nearby barrier reef, creating a breeding ground for 50 male and 50 female conchs. During the breeding season, March to September, each female laid about one egg mass a month (each mass contains up to 500,000 tiny eggs). Scuba divers daily remove the eggs from the 30-foot-deep farm, moving them to the lab where they are cleaned and monitored.

Three days after arrival, most of the more fertile masses hatch, exposing tiny, free-floating conch larvae. After three months of nourishment, the conchs are about an inch long and are likely to survive. After 2 to 2 1/2 years of growth, the mature mollusks are ready for harvest.

''We've shown that conch can be raised in a hatchery,'' says Ms. Davis. ''The question now is: What do you do with them after you raise them (to juvenile stage)?'' Despite the promise of a widening market for the queen conch, grow-out methods (ways to raise conch from the juvenile stage to the harvestable stage) still remain to be tested.

Although aquaculture is an ancient practice, conch mariculture has started to attract scientific attention only in the past three years. On the Turks and Caicos Islands, which lead the Caribbean in conch exports, PRIDE officials have encouraged the island-government to pass legislation supporting marine conservation and mariculture.

PRIDE director Chuck Hesse, who has been studying the queen conch in the Caribbean since 1975, says the '83 hatching season could go a long way to ensure the success of conch mariculture in the region. ''We're talking about food. We're talking about island economies. We're talking about self-sufficiency. This is more than just a gastropod with a pretty shell,'' he says.