Page:Popular Science Monthly Volume 82.djvu/553

Rh pearls have been found with the remains of Indians. If only well preserved, some of these pearls at present would be worth as much as five hundred dollars.

In many places where the abalone was formerly abundant, the large individuals of legal size are taken and it may be true, as in the case of the American lobster, that in this manner the most prolific breeders are sacrificed. We do not yet know anything about the breeding habits and embryology of any species of abalone, and hence are not certain as to the best months for a closed season. In time, without doubt, we shall be able to artificially propagate the abalone, as has been done with the oysters, clams, lobsters and other useful animals. The government breakwater, at the mouth of Los Angeles harbor, at San Pedro, has become a natural breeding ground for black abalones which creep back under the great stone blocks and thus escape the gatherers, who are stripping every accessible niche and cranny along the coast at each low tide during the open season.

Reservations have been established at Monterey Bay and Venice, but the present laws are inadequate for their best development. By act of the city trustees, the Venice breakwater has been made a biological reservation under the control of the marine biological station of the University of Southern California and guarded by a deputy of the State Fish and Game Commission. As an aquacultural experiment I have placed colonies of several hundred black abalones and seventy-five of the green species upon the submerged rocks. A large concrete livebox has been suspended by a block and tackle hoisting apparatus at about the mid height of the tide. The open top is covered by heavy galvanized iron meshwork, while through several holes in the bottonbottom [sic] the dirt is cleaned out by the flow of the tide. The box is so heavy that one may stand upon any part of it and do the necessary work in feeding and observing the animals within. Forty abalones under experimentation and for growth records are kept in the live-box and a group of two or three times that number might easily be maintained in good condition. Near Venice the ocean is shallow, for it is three miles out to the sixteen-fathom line. The trawling of our motor-sloop, the Anton Dohrn, has demonstrated that in most places the fauna of the sandy bottom is poor. Better results may be looked for when reservations are located on the rocky coast, where great beds of kelp thrive just within the deep-water line. The kelp is not only important as food for abalones, but within its wide spreading fronds a world of living things thrive. In such a region the plankton is richer and these microscopic plants and animals generate food for the larger swimming and bottom-dwelling forms.

The establishment of laws for the regulation of aquaculture and the concomitant protection of marine and fresh-water organisms is of