“It was a nice day to be in the water, provided nature gave you fins or a shell.But for divers Betsy Peabody and Joth Davis, in pursuit of the rare Olympia oyster, conditions Thursday were rather less welcoming. With a brisk and chilly-sounding “WOO!” the pair disappeared beneath the waters of an enormous pool on the grounds of a Port Madison estate.Over the next 20 minutes, they emerged with about 150 of the jagged, rust-colored mollusks, dislodged from the pool wall and bound for a spawning tank on Hood Canal.“It seems a bit loony to be doing this in December,” said Peabody, visibly shaking in the cold afternoon air after the dive. “But December is the ideal month.”That’s because the “brood” oysters will spawn in a laboratory tank over this spring. The yield will be an estimated 150,000 oyster seed, to be released into the wilds of Liberty Bay near Poulsbo next summer.And with that, a population may be reborn.“These are like our emissaries from Bainbridge Island to the peninsula,” said Peabody, who organized the project as director of the Bainbridge-based Puget Sound Restoration Fund. The dive marked an unlikely stop on the quest to revive the rare oyster stock, the tale of which mirrors the wax and wane of many other Puget Sound fishery resources.Found from Alaska to Baja California, the Olympia oyster was long enjoyed by Washington’s indigenous tribes. Explorer Capt. Vancouver and his crew sampled the oyster when they dropped anchor in Discovery Bay, the first recorded non-native harvest.The oyster later supported a thriving commercial industry and was exported to other states. But stocks were severely depleted by overharvesting in the 19th century, then fell victim to industrial pollution from pulp mills and other sources in the south-sound area from the 1930s to the 1950s.The oysters were largely replaced by the now-common Pacific oyster – transplanted from the Far East in the 1920s – a hardier stock that thrived in the Puget Sound area in conditions that felled their predecessors.But although fewer in number and smaller in size than the Pacifics, Olympias have their adherents among shellfish connoisseurs, and are still hailed as among the most savory in the world.Among those on hand Thursday was Hal Beattie, who works for the state Department of Fish and Wildlife at its Point Whitney laboratory on the Hood Canal from Seabeck.The oyster transplant is ideal and should succeed, he said, because of the geographical proximity of Port Madison and Liberty Bay.The department had been looking at an array of troubled marine species, Beattie said, but despite a plan for rebuilding the Olympia oyster stock, there was no funding available.Along came Peabody.“Here we had a project with no funding, and a group that was looking for a project,” Beattie said. “It was a nice union.”Established in 1997, the non-profit PSRF tackles all manner of marine restoration projects, including streams, wetlands and shellfish beds. The fund relies on grants from various businesses and corporations, private individuals and the Suquamish Tribe. The PSRF hopes to bring back the Olympias by restoring the stock to local inlets and bays. The Bainbridge-to- Liberty Bay effort, funded by Fred Hill Materials, is their seventh such project.Through roundabout means, word got to Peabody that a cache of Olympias could be found in an unusual saltwater swimming pool on the shores of West Port Madison.That led her to John and Ann Powel, who have been enjoying both the pool and the oysters since moving to the island in 1954.“Before breakfast, with no clothes on,” said the impish John Powel of his preferred manner of swimming. “It’s the only way.”Onlookers Thursday were curious as to why the Olympias could only be found on the pool’s south wall.Powel said the family has kept the other three sides scraped bare of shellfish, “because we got tired of having to bind up cuts.”Powel, a great lover of seafood, counts himself among the fans of the Olympia oyster.“Sweet little things,” he said. “I love ‘em.””