ARTIFICIAL PROPAGATION OF OYSTERS. 13 



COLLECTION AND TRANSPLANTING. 



An important consideration in placing artificial propagation on a 

 commercial scale is that of collecting and transplanting heavy " sets " 

 by a method that would be practical and efficient. A variety of 

 collecting materials Avas tried out in Milford Harbor to determine 

 just how certain ones would weather unfavorable conditions on the 

 beds. A new type of collector for handling artificially propagated 

 oyster spat was made from cardboard egg-crate partitions, which 

 were dipped in hot paraffin and then covered with coarse sand (see 

 fig. 2). The}' quickly sank to the bottom and were heavy enough 

 to withstand tides and storms in a moderate depth of water. The 

 partitions remained in place for over a month when suspended at the 

 surface of the water, and longer when placed on the bottom, and 

 regardless of how they are dropped into the water they settle in such 

 a way that there is no chance of smothering the spat. They are 

 cheap collectors, capable of collecting thousands of spat and in two 

 or three months will break up, producing large numbei's of small 

 single oysters, the most desired product in 03'Ster culture to-day. 

 The degree of spat concentration that is most suitable will be deter- 

 mined by future experiments. 



Other objects, such as brush, rope, netting (fig. 7), shells (fig. 9), 

 tin cans, etc., coated with paraffin and sand, asphalt, cement, and 

 plaster of Paris were also found suitable to some extent as col- 

 lectore. The artificially propagated spat were caught on a sea-scallop, 

 clam and oyster shells, and small clay flower pots, as there were 

 not sufficient numbers to warrant using the larger collectors. The 

 loss of spat from handling or otlier agencies was less than 1 per 

 cent, and in transplanting them to the most suitable grounds no 

 greater loss should be sustained if they are properly liandled. The 

 problem of catching and handling the set is insignificant in com- 

 parison with that of producing larva? ready to attach themselves, 

 and improvements in this respect will quickly come when a depend- 

 able method for the latter has been perfected. 



SUMMARY. 



The primary object in writing this paper is to lay before prac- 

 tical oyster growers and biologists the various problems that have 

 made artificial propagation of the oyster a difficult task, and to 

 briefly describe experiments used in finding some solution for them. 

 The summer's work was conducted for the purpose of studying these 

 ])roblems more thoroughly and to make detailed observations of 

 the many natural conditions in the environment of the oyster to 

 determine the influence they exert upon the eggs, embryos, and free- 

 swimming larvtc. The continuation of this work in the future will 

 aim to develop this method on a production basis so that it may be 

 perfected to such an extent as to be of value to the practical oyster 

 industry. 



Northern oyster growers are to-day paying as high as $1,000 for 

 1,000,000 yeai--old oysters, or for one-fiftieth of the number that a 

 single full-grown female oyster is capable of producing. 



