The Growth of the Soft Clam 313 



covered with stagnant water, until, after many days, a 

 scum of bacteria had formed over them. Seed for 

 planting could be kept in good condition out of water for 

 several days in a comparatively low temperature. 



Great numbers of soft clams have been dug from local- 

 ities where the water contained very little salt, and 

 planted where the salinity was very high, apparently be- 

 ing not at all affected by the transfer. Great changes in 

 salinity have a markedly bad effect on oysters, interfer- 

 ing especially with reproduction; but soft clams breed 

 well in either extreme. This condition, that requires so 

 much attention from the oysterman, may probably be 

 entirely disregarded by the clam culturist. 



No rule can be formulated to govern the volume of 

 seed to be sown on a specified area, for one part of the 

 bottom will support several times as many clams as an- 

 other, and a bushel of very small seed clams should be 

 spread over a larger space than if they were of greater 

 size. In a report on the Essex experiment it was stated 

 that about five hundred bushels of seed were required 

 properly to plant an acre. This is an excessive number 

 for the most favorable parts of any flat, even if the clams 

 to be planted were relatively large. Very few perhaps 

 four or five bushels of half-inch clams would be re- 

 quired to fill the best acre that could be selected, and the 

 best acre would support many times the number that 

 could exist on some of the poorer ones. Only experi- 

 ence will indicate the quantity of seed of a certain size 

 that will produce the best results on a specified area. 



The recent extensive experiments of the Massachusetts 

 Fish and Game Commission show that, on a flat of 

 ordinary fertility, ten or fifteen clams to the square foot 

 are as many as can maintain a maximum rate of growth. 



