Pearl hunting, also known as pearling, is the activity of recovering pearls from wild molluscs, usually oysters or mussels, in the sea or freshwater. Pearl hunting was prevalent in the Persian Gulf region and Japan for thousands of years. On the northern and north-western coast of Western Australia pearl diving began in the 1850s, and started in the Torres Strait Islands in the 1860s, where the term also covers diving for nacre or mother of pearl found in what were known as pearl shells.
In most cases the pearl-bearing molluscs live at depths where they are not manually accessible from the surface, and diving or the use of some form of tool is needed to reach them. Historically the molluscs were retrieved by freediving, a technique where the diver descends to the bottom, collects what they can, and surfaces on a single breath. The diving mask improved the ability of the diver to see while underwater. When the surface-supplied diving helmet became available for underwater work, it was also applied to the task of pearl hunting, and the associated activity of collecting pearl shell as a raw material for the manufacture of buttons, inlays and other decorative work. The surface supplied diving helmet greatly extended the time the diver could stay at depth, and introduced the previously unfamiliar hazards of barotrauma of ascent and decompression sickness.
History
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 beads.
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.
Asian
In Asia, some pearl oysters could be found on shoals at a depth of from the surface, but more often divers had to go or even up to 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.
Pearl divers near the Philippines were also successful at harvesting large pearls, especially in the Sulu Archipelago. In fact, pearls from the Sulu Archipelago were considered the "finest of the world" which were found in "high bred" shells in deep, clear, and rapid tidal waters. At times, the largest pearls belonged by law to the sultan, and selling them could result in the death penalty for the seller. Nonetheless, many pearls made it out of the archipelago by stealth, ending up in the possession of the wealthiest families in Europe. Pearling was popular in Qatar, Bahrain, Kuwait, Japan, India and some areas in Persian Gulf countries. The Gulf of Mexico was particularly famous for pearling, which was originally found by the Spanish explorers.
