REPORT OF COMMISSIONERS OF INLAND FISHERIES. 37 



PART II. QUESTIONS OF ECONOMIC IMPORTANCE. 



The purpose of the inquiry into the life history and habits of the 

 clam has been to ascertain how to control the conditions upon 

 which the yield of clams depends. The scientific results have in- 

 dicated the solution of the practical problems at every step. From 

 the economic point of view there are two general problems, viz., 

 the causes of the present depleted condition of our clam flats, and 

 the means of restoring or increasing the natural yield. 



PHYSICAL CAUSES OF THE DEPLETION OF THE CLAM BEDS. 



In view of the many adverse physical conditions and natural 

 enemies with which the clam has to contend from the time the 

 egg is laid until maturity, the chances of an individual's reaching 

 the adult condition would seem to be almost infinitesimal. The 

 minute, unprotected eggs, extruded wherever the female may happen 

 to have burrowed, lie upon the ground or are swept into the cur- 

 rent, and there await the arrival of the spermatozoa which are ex- 

 truded into the water by the male. It is, of course, impossible to 

 say how great are the chances of non-fertilization. 



When the eggs have developed into swimming larvae they are 

 still at the mercy of the tides; they may be carried out to sea or 

 lodged in muddy, rocky, or otherwise impossible places. Those which 

 have successfully set and even burrowed may still be destroyed by 

 shifting sand or silt, or washed out of their burrows and exposed to 

 their many enemies. At times clams, an inch or more in length, are 

 found dead in immense numbers, apparently from the effects of the 

 excessive heat, where 'the shore is underlaid with hard clay and cov- 

 ered with a thin layer of sand in which the clams have burrowed. 

 At Pawtuxet, during the past year, great quantities of clams 

 were found dead, and several visits to the flats failed to reveal any 

 other cause than the one just suggested. 



Not infrequently clams in a particular region appear to die of 



