REPORT OF THE COMMISSIONER OF FISHERIES. 81 



While the field work in the investigation of Chesapeake Bay closed 

 during September, 1916, the detailed study of materials collected, 

 which is necessary for the drawing of conclusions, remains to be 

 finally completed; however, substantial progress has been made. 



SHELLFISH INVESTIGATIONS. 



Provided with a more adequate personnel for attention to the 

 problems of the oyster industry, the Bureau has been able to set 

 these investigations upon a basis promising and already yielding 

 greater efficiency and more practical service to the oyster industries. 

 A provisional field laboratory has been established at Milford, Conn., 

 from which as a base the principal problems of the great oyster- 

 planting industry on Long Island Sound and other waters are being 

 considered. The problem of finding the conditions necessary to 

 secure a regular ''set" of 03^sters is given first place, although atten- 

 tion is given from that headquarters to other important matters, 

 such as the destruction or damaging of oyster beds by the growth of 

 the so-called "sand coral." 



There has been cooperation with the Conservation Commission of 

 Maryland in observational ancl exiDerimental work on the growth 

 of oysters in Chesapeake Bay. Through the Woods Hole laboratory 

 further attention has been given to the study of OTeen gill in oysters 

 of Lynnhaven Bay and other localities, and studies of some impor- 

 tance have been addressed to the nutrition of oysters. The results 

 of both of these latter investigations have been given out in published 

 reports. Tlie Bureau has continued to extend aid to the oyster 

 investigations of Puget Sound undertaken in cooperation with the 

 University of Washington. 



Serious mortalities among oysters or injuries to oyster beds occurred 

 during the year in regions remote from each other and from distinct 

 causes in the several cases. Among these was the damage to oyster 

 beds from "sanding," owing to the work of polychsete worms in 

 building tubes of sand and overrunning, or even smothering, the 

 oysters; it was most prevalent in Jamaica, Great South, and Hemp- 

 stead Bays. The loss of large numbers of planted oysters in Chesa- 

 peake Bay was investigated and the results were made known to 

 persons interested. On the west coast of Florida there occurred very 

 serious losses of oysters resulting from the depredations of a turbel- 

 larian worm, locally but improperly known as a "leach." A less 

 misleading and more appropriate name is that of "wafer," which is 

 applied to a similar pest in New South Wales. This form had not 

 previously been recorded as an enemy of oysters in this country. 



Mortality among scallops in Maine was investigated and found to 

 be attributable to the work of starfishes, which were made more 

 abundant by the pursuit of improper practices in the scallop fishery. 

 Appropriate recommendations were made. 



Investigations relating to fresh-water mussels have been continued 

 actively. Interesting progress has been made in experiments in 

 rearing mussels under conditions of control since it has been found 

 that mussels (Lake Pepin muckets) reared in confinement from arti- 

 ficial infections begin breeding at the age of little more than two 

 years. A second generation is now being reared from parents which 



