| Introduction Two pearl oyster species are found along the Pacific coast of Mexico and especially along the coast of Lower California. The pearls produced by these species have been well known for many years. Ancient tribes of Mexico, honored pearls and used them for both rituals and ornaments. This is known from archeological discoveries of relics and also from early chronicles which mention Indians of both sexes wearing pearls. Christopher Columbus was undoubtedly the first European to discover that there were pearls in American waters in 1492. Nevertheless, European knowledge of pearl resources in Mexico dates from the conquest by Hernan Cortes in about 1522. The diary of his lieutenant, Fortuna Ximenes, mentions the discovery of native chiefs living in primitive huts along the sea shore, with quantities of beautiful pearls lying carelessly around. In fact, Cortés secured large quantities of the gems from a tribe near the present site of Hermosillo in the state of Sonora. In 1535 the location of pearl reefs was prominently displayed on Cortés' map of this coast. Following Cortés' explorations of the Pacific Coast of Mexico (1533-1538), a number of expeditions were equipped for securing the pearls either by trading with the natives, or in many cases forcing the natives to fish for the pearl oyster species. This latter contact with the Spanish resulted in very bitter feelings on the part of the Indians. It therefore became risky for small traders to venture among them. Arrival of the Jesuits to western Mexico in 1642 led to more amicable relations with the Indians and the restoration of harmony resulted in more favorable development of the fisheries. This fishery became so profitable for the Spanish and sailors stationed in the Gulf of Cortez that they were frequently requested to devote more attention to the fishery of pearls than to their official duties. To stop this practice, in 1884 President Manuel Gonzalez inaugurated the policy of granting exclusive permits to pearl reefs. In that year, five permits were granted for a period of 16 years, giving exclusive rights to all fisheries in the respective zones. These five grants were immediately funded by French and British companies, which promptly had very profitable fisheries. Their success was remarkable. Dozens of fishing boats fully equipped with air pumps allowed men to work in deeper water than the divers were able to exploit. From the Spanish conquest until 1874, the Mexican pearl fishery was conducted exclusively by divers without any equipment. After 1880 this method was replaced by the use of diving apparatus. From then on, the pearl fishery became a well-organized industry. Commercialization of shells for the clothing and fashion market became the main economic support of this activity. It was estimated that from 1580 to 1857, 95,000 tons of pearl oyster shells were removed from the Gulf of California. In 1857, to establish regulations for resource conservation and protection of the reefs, the Mexican government divided the Gulf of California into four pearling districts and provided that only one of them could be exploited each year. This allowed the reefs to remain successfully undisturbed for three years. At the same time, efforts to produce pearls from cultured animals were conducted in different regions. The first spherical pearls are claimed to have been produced between 1890 and 1893 by William Saville-Kent in the Thursday Islands, Australia. The first patents for the procedure were filed independently by two Japanese, Dr. Nishikawa and T. Mise, who are believed to have sourced their knowledge of specific techniques from Saville-Kent. A joint patent was awarded after a series of court battles. Gastón Vivès and General B. Topete, the latter the municipal president of La Paz, capital of Lower California, commissioned a study for introducing pearl oyster culture to this region. This included knowledge about appropriate environmental requirements, the comprehension of biological processes, and the knowledge of various techniques for the extended culture of pearl oysters. The pearls produced were exclusively derived from natural sources; nuclei implantation techniques or other artificial procedures were never used. Culture activities were primarily conducted in San Gabriel Cove, at Espiritu Santo Island, Mexico. This station was in permanent communication with the city of La Paz, through sail and steam boats which traveled two or three times per week. Company administration resided in La Paz, while on the Island foreman supervised all the technical operations, In 1939 the government banned the pearl oyster fishery. More recently, several research activities have been devoted to the investigation of "Mexican pearls," some of them to collect scientific information, and others with an eye towards launching a new business enterprise. Preliminary results have been encouraging, and the establishment of two enterprises for pearl production is expected. | 
