Careful coast surveys have been followed by the extension of the present oyster-growing areas, and the establishment of beds in new regions deemed suitable for this purpose. The southern and western coasts have at various points been successfully colonised by the oyster of the Chesapeake.
There is no attempt at completeness in the following account of oyster culture, based upon observations made in the spring of 1906, on Great South Bay, Long Island, near the end of the oyster harvest. Whoever desires all the facts and figures can get them easily. Oyster culture is a science; its study has produced a great body of literature on the subject. The report of the United States Commission of Fish and Fisheries for 1892 contains "A Bibliography of Publications in the English Language relative to Oysters and the Oyster Industries." Planting Oysters.— In making new beds men follow Nature's pattern. Choosing a location free from too severe currents, supplied with food, and ranging in depth under eighteen fathoms, the oyster-grower cleans away debris and prepares a shell bottom for the spat to light upon. It is often found that areas thus pre pared will soon be full of young oysters, though no "seed" is laid down. The young fry drift far from their home grounds, and alight in localities suitable for their development.
"Clutch" and "stool" are technical terms applied collectively to any clean, firm body placed in the water for the attachment of spat. Oyster shells are most commonly used, being thrown broadcast from boats over the area intended for a new bed. Where mud is likely to submerge single shells, they may be dumped in heaps. Hard bottoms require the least quantity of shells. Muddy bottoms may require several "sowings," which gradually form a solid crust above a muddy sub-stratum.
Oystermen go to the east end of Long Island and get boat 427 The Oysters loads of the little "jingle shells" (Anomia) to put down. Spat that settles on jingle stool becomes separated by the disintegra tion of the thin shells in a year or two. Scallop shells are also used. Tin cans have been tried ; the salt water rapidly eats through them, liberating the individual oysters. Light weight shells are liable to be washed away with their loads of young oysters by strong tides or currents. Oyster shells strung on wires
and hung between submerged posts are good spat-catchers. But this plan involves too much labour. Brush and straw are used somewhat on muddy bottoms, and where currents are strong.
The Chinese have for centuries grown oysters on bamboo screens in the estuaries of rivers. The French, who have no natural oyster beds, have constructed an elaborate and successful artificial system of oyster culture, by converting worthless mud flats into pans and claires. Here they grow and fatten oysters for the Parisian market, which is the most exacting and the best paying market in the world.
The most perfect device for catching spat :s used by French growers. Hollow tiles, coated with cement, inside and out, and piled crosswise in wire trays, are suspended between posts under water. The entire surface becomes covered with spat. In due season the young oysters are chipped off with the cement; thus separated, they develop in perfect form in trays where they are never allowed to become crowded.
In this country we still have natural beds in a productive state. Comparatively speaking, oysters are cheap and labour is dear. Conditions on the French coast are reversed. The most perfect methods of culture cannot profitably be adopted in the present state of the industry. Dr. Brooks's important dem onstration that the ova of oysters can be artificially fertilised and carried safely over the critical embryonic stages, has, as yet, no practical bearing on the business.
Thinning and Transplanting.—The mangrove oyster illus trates the logical consequences of too much crowding. Spat which coats the clutch completely the first year enters upon a struggle for existence which warps and stunts the growth of all. So many feeding must often face comparative starvation.
When the spat is a year old,. and the size of a twenty-five cent piece, the business of thinning and transplanting may well begin. A good "set" should furnish quantities of spat for planting 428 The Oysters new oyster beds, profitable to the owner for extending his acre age, or in sales as "seed" to other oyster growers.