Pearl fishery

Pearl hunting is the act of recovering pearls from oysters in the sea. Pearl hunting used to be the prime industry in the Persian Gulf region and Japan.

Before the beginning of the 20th century, the only means of obtaining pearls was by manually gathering very large numbers of pearl oysters or mussels from the ocean floor or lake or river bottom. The bivalves were then brought to the surface, opened, and the tissues searched. More than a ton were searched in order to find at least 3-4 quality pearls.

In order to find enough pearl oysters, free-divers were often forced to descend to depths of over 100 feet on a single breath, exposing them to the dangers of hostile creatures, waves, eye damage, and drowning, often as a result of shallow water blackout on resurfacing. Because of the difficulty of diving and the unpredictable nature of natural pearl growth in pearl oysters, pearls of the time were extremely rare and of varying quality. The Great Depression in the United States made it hard to get good prices for pearl shell. The natural pearls found from harvested oysters were a rare bonus for the divers. Many fabulous specimens were found over the years. By the 1930s, overharvesting had severely depleted the oyster beds. The government was forced to strictly regulate the harvest to prevent the oysters from becoming extinct, and the Mexican government banned all pearl harvesting from 1942 to 1963.

In Asia, some pearl oysters could be found on shoals at a depth of 5–7 feet (1.325–2 meters) from the surface, but more often divers had to go 40 feet (12 meters) or even up to 125 feet (40 meters) deep to find enough pearl oysters, and these deep dives were extremely hazardous to the divers. In the 19th century, divers in Asia had only very basic forms of technology to aid their survival at such depths. For example, in some areas they greased their bodies to conserve heat, put greased cotton in their ears, wore a tortoise-shell clip to close their nostrils, gripped a large object like a rock to descend without the wasteful effort of swimming down, and had a wide mouthed basket or net to hold the oysters.

For thousands of years, most seawater pearls were retrieved by divers working in the Indian Ocean, in areas such as the Persian Gulf, the Red Sea, and in the Gulf of Mannar (between Sri Lanka and India). A fragment of Isidore of Charax's Parthian itinerary was preserved in Athenaeus's 3rd-century Sophists at Dinner, recording freediving for pearls around an island in the Persian Gulf.

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