THE OYSTER AND THE OYSTER INDUSTRY. 29 



ing of ground for this purpose and dependence is placed largely on 

 natural beds for the supply of oysters. 



In some few cases a State plants a limited amount of cultch upon 

 certain partially depleted natural beds for public benefit. In gen- 

 eral, however, the natural beds are staked off and reserved for general 

 pubhc use by the ''natural growther" subject to certain restrictions, 

 mentioned elsewhere. 



The prmcipal considerations mvolved in this method of oyster cul- 

 tm-e are character of the cultch, character and preparation of the 

 bottom, time for planting cultch, the proper location of cultch beds 

 with respect to tides and cun-ents and the spawning oysters, and the 

 location of beds of spa^^Tlmg oysters. 



Cultch. — While formerly limited use was made in the United States 

 of various forms of cultch — such as tin cans, bits of pottery, brush, 

 pebbles, "jmgle" shells, and oyster shells — only the last three mate- 

 rials have proved to be of practical value, and at the present tinie the 

 cultch used consists almost entirely of oyster shells. A few " juigle" 

 shells arc kno\m to be employed at one point in Long Island Sound. 

 Oyster shells ai'c large and afford surface for the attachment of quan- 

 tities of spat (PI. IV). As this grows, overcrowdhig is apt to result, 

 since the shells are too heavy to be broken apart by the pn^ssure of 

 the developing set. This is overcome l)y breaking apart and culling 

 the clusters thus formed. 



The advantages of oyster shells as cultch consist largely in their 

 general adaptability, presenting a smooth surface for the attaclmient 

 of the set, and their abundance and convenience, shice an oyster- 

 shuckhig house has only to turn about and convert its shell pile into 

 spat collectors by the use of its own boats. At the same time the 

 gradual disintegration of the shells provides lime for the succeeding 

 generations. 



"Jingle" shells, or silver shells, belonging to the species of Anomia, 

 and scallop shells are thinner and more fragile than oyster shells. 

 Consequently, they make a suiierior form of cultch, since the pressure 

 of the growing young oysters t)reaks them apart and the formation of 

 clusters is prevented. Unfortunately, the suppl}' of such shells is so 

 limited that very few are now used. 



Cliarader and vrfparation of hoitom.- — If the bottom at the pohit 

 where it is desired to plant cultch is sufTiciently hard to support it a 

 layer of shells is spread upon it broadcast, as previously described. 

 In case the bottom is soft, it may ])e prepared by putting down sand 

 or gruvel in suflicicnt quantities to support the shells. Often, how- 

 ever, the ])()ttom is stinened merely by the use of shells. Sulhcient 

 quantities arc put down and allowed to sink, until a substratum is 

 formed firm enou^^h to support a layer of cultch several inches or a 

 foot thick above tne gromid. A ])ed on which cultch has been placed 

 for severul years in succession will gradually be made firmer by the 

 setting of a part of the shells. 



Time for planting cultch. — Since sea water always contains more or 

 less suspencTed de])ris, which gradually settles upon the bottom or any 

 object thereon it follows that cultch will more or less rapidly become 

 coated with a layer of slime or debris. If this becomes too thick the 

 oyster liirvy; an^ ])revented from setting upon it. Mov(^ment of the 

 water by tifh'S and currents obviates this difneulty somewhat by 

 washing the debris from the cultch. In bodies of water where there 



