128 American Fisheries Society 



clam. (2) Eel-grass prevents the circulation of water, 

 collects slime and silt and furnishes a mass of decaying 

 material injurious to the clam. (3) Mussels ruin a 

 clam flat by collecting soft mud, covering the clams and 

 utilizing the same food. (4) Organic material from 

 various sources in a soil corrodes the shell and interferes 

 with the shell-forming properties of the mantle. In cer- 

 tain river flats manufacturing wastes, chiefly of the 

 petroleum group, render the clams unpalatable, the sur- 

 face unfit for set, and, in extreme cases, may destroy the 

 adult clams. (5) Shifting sand does not favor the 

 growth of clams, although adult clams will stand a sur- 

 prising amount of shifting. Flats with a slightly rippled 

 surface are barren because the young clams cannot get 

 a permanent foothold, but such soils respond to cultiva- 

 tion provided that the shifting is not too severe and that 

 large seed clams are planted, although the culturist runs 

 the risk of storms and swift tides destroying his crop. 



Practical Applicatio7i. — The points brought out in this 

 paper are of practical application in two ways, to the 

 clam culturist in selecting the location of his grant and 

 as a basis for methods of reclaiming a large area of 

 barren flats. The only way the tidal flats of Massachu- 

 setts and other states can be made truly productive is by 

 a system of individual leases under which every fisher- 

 man can have a salt water farm for the production of 

 shellfish. 



In selecting his grant the prospective culturist should 

 bear in mind that the current is the most important 

 guide, since the productive capacity of a clam flat 

 depends chiefly upon the circulation of water, and he 

 can follow the general rule that as long as the flow of 

 water does not harm the clam in other ways the swifter 

 current gives the faster growth. Yet he should not for- 

 get that there may be disadvantages as well as 

 advantages, excessive action causing the shifting of the 

 flat, destruction of clams and the prevention of set, and 

 that no hard and fast rule can be stated. 



