326 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



the shells contain pearls or not. The shells reach their full size when 

 they are seven years old. The average weight of the empty shell at 

 that time is about 1 pound, and the length varies from 10 to 18 inches. 

 When the animal has reached maturity, it tears itself loose from the 

 stones, opens its shell, and dies. The shells are then covered with corals 

 and parasites. They become worthless and the pearls are lost. These 

 mollusks also have a number of enemies, the most dangerous of which 

 is a kind of Scolopendt'a, which opens the shells and eats the mollusks. 

 All grown mussels are, moreover, infested by crustacean-like parasites, 

 which penetrate into the shells and there lay their eggs. 



After the oysters have been caught and brought ashore by the divers, 

 they are sorted. The shells are opened with a steel knife. A skilled 

 hand can open a ton per day, and not miss a single pearl. The mother- 

 of-pearl is laid in a shady place, that the colors may not fade. When 

 there is a famine, the mollusks are eaten by the natives. The pearls 

 are generally found in the place where the band before mentioned starts. 

 In shells where many i^earls are found, they are generally small and 

 misshaped. Occasionally pearls are found loose in the shells. These 

 are always of a very fine quality, perfectly round, and often very large. 

 But there is hardly one in a thousand oysters which contains such 

 pearls. The natives often lose them, owing to the careless way in which 

 they open the shells. 



Fine and calm weather is most favorable for i^earl fishing. The divers 

 wear no special suit, but simply rub their body with oil, so the sun may 

 not blister their skin. They remain under the water one to two minutes, 

 and bring up oysters from a depth of 20 fathoms. They rarely go to 

 such a depth, but the finest oysters are found there. Thus iu many 

 fishing-grounds, which were supposed to be exhausted, a great many 

 pearl-oysters are found iu deep water. 



In the Southern Pacific, pearl fisheries are principally carried on near 

 the Kavigator's Islands in the Tuamotu Archipelago. Many of these 

 fishing-grounds are partly and some are eutirel}" neglected. Thus the 

 Island of Manihiki twenty years ago yielded 100 tons of shells in eight- 

 een months ; but since that time no pearl fisheries have been carried 

 on there. The Hogoleu Lagoon is also known as a vast unexplored pearl- 

 oyster bed. So far the Tuamotu Archipelogo is said to have produced 

 25,000 tons of mother-of-pearl, valued at 18,000,000 crowns [$4,821,000]. 

 o^early the entire quantity goes to Tahiti, to be exported thence. In 

 1873 2,000 tons of shells were exported ; the pearls having a value of 

 about 140,000 crowns [$37,520]. In 1878 Tahiti exported 591 tons of 

 shells, valued at 038,280 crowns [$171,059.04], and pearls valued at 

 108,000 crowns [$28,944]. In 1879 there were exported 470 tons of 

 shells, valued at 507,000 crowns [$136,030.80], and pearls valued at 

 72,000 crowns [$19,29G]. In 1875 an export duty of 30 crowns [$8.04] 

 per ton was levied 5 this duty, however, was abolished iu 1878, and 

 eiuce that time the exportation has again increased. 



