Other
concessions were given covering the ocean shore of Lower California,
the eastern side of the gulf within the States of Sonora and Sinaloa,
and the ocean shore of Mexico southward from Sinaloa. In addition to
these, certain territorial rights of fishing are claimed through grants
dating back very early in the history of the country. So eagerly have
these concessions been sought in recent years, that there is now little
pearling ground on the coast which is not under corporate or private
claim. And, owing to speculation in these concessions and in the
formation of companies to develop them, it is somewhat difficult to
obtain wholly reliable data relative to the condition and extent of the
industry.
Two species of pearl-bearing mollusks occur on the Mexican coast. The principal one is the M. margaritifera masatlanica, known locally as the concha de perla fina. This
species is closely related to the "black lip shell" of the Australian
coast. It is considerably larger than the Venezuelan oyster, averaging
four or five inches in diameter and attaining an extreme diameter of
seven or possibly eight inches. It occurs to some extent all along the
Pacific coast of Mexico, in detached beds intercalated in places. The
principal reefs, which have been exploited for nearly four centuries,
are in the shallow waters of the Gulf of California and especially
within the 300 miles between Cape San Lucas and Mulege Bay. The
fisheries have centered about the islands of Cerralvo, Espiritu Santo,
Carmen, and San José, and in the bays of Mulege, Ventana, and San
Lorenzo. The depth of water on the reefs ranges from two to twenty-five
fathoms, with an average of probably six or eight fathoms. The species
is generally isolated, and firmly attached by the byssus to the bottom
rocks or the stone corals, from which it may remove in case of
necessity, though it probably does not do so frequently.
The second species is known locally under the name concha nacar, and has been named Margaritifera (Avicula) vinesi (Rochebonne).1 It
occurs only in the northern part of the gulf near the mouth of the
Colorado River. Formerly it was abundant in that region, occurring in
large areas, but it has become much reduced and is now little sought
after. It is claimed that this species is far more productive of pearls
than the M. margaritifera, and that it yielded the large
quantities obtained by Osio in the eighteenth century. Although
iridescent, the shell is so thin and convex that it is without
commercial value.
The
headquarters of the Mexican pearl fishery are at La Paz, the capital of
Lower California, 240 miles northwest of Mazatlan and 150 miles north
of Cape San Lucas. This "Mantle of Peace"—the literal translation of La
Paz—contains about 5000 inhabitants, nearly all of
1 Diguet, "Bulletin de la Société Centrale d'Aquiculture," 1895, Vol. VIL
