REPORT OF THE COMMISSIONER OF FISHERIES. 23 



During the year a plague of mussels interfered seriously with 

 the oyster industry of Chesapeake Bay. An investigation in Decem- 

 ber and January indicated that the distribution of the mussels was 

 limited within a narroAv range of salinity of the water and was 

 probably due to the paucit}'^ of rainfall during the preceding sum- 

 mer. This is one of the oysterman's troubles that is beyond control 

 but that, while costly during its prevalence, will correct itself. 



POLLUTION OF WATERS. 



Pollution of interior streams and waterways by industrial wastes 

 and municipal sewage has been the subject of complaint and protest 

 for many years. Industry, itself, frequently has been a victim of 

 its own acts through inability to use the polluted water Avith safety 

 in boilers or for the many other industrial purposes that require 

 pure water. The public health has been menaced, public works have 

 been damaged, agriculture has suffered, and in some parts of the 

 country the streams have been swept bare of living things, includ- 

 ing fishes and other animals of economic importance. Recently the 

 vast development of petroleum production and transportation, the 

 use of its derivatives for manifold purposes ashore, and particularly 

 as fuel on ships, has introduced a new element of serious pollution in 

 the great harbors and in places on the open coast. 



The pollutions are almost as varied as industry and in many cases 

 are not only complex in themselves but are further complicated by 

 their reactions on one another and on the natural constituents of the 

 waters themselves. The waters can not be restored to their pristine 

 purity, nor to any state approaching it, by mere legislative fiat, 

 and the sooner that fact is appreciated and constructive measures 

 are taken the better for the public welfare. 



The pecuniary losses now suffered as the result of water pollutions 

 are enormous, and the preventable damage to the life and beauty 

 of our streams, lakes, and seacoast is beyond estimate in terms of 

 mere money. If existing abuses are to be corrected and new ones 

 prevented Avithout inflicting widespread economic injury, something 

 more constructive than drastic laws must come into being. There 

 must be corrective legislation, but it should be based on something 

 more substantial than a perfectly justifiable desire for improve- 

 ment. Complete utilization of raw materials is an ideal not attain- 

 able. Industry must be accompanied by " waste," and the wastes 

 must be disposed of in some manner. The problem is to devise ways 

 of disposing of them so as to minimize their harmfulness while still 

 permitting industrial development. This is the problem of the 

 biologist, the chemist, and the engineer working in cooperation. 



The effects of these pollutions on the fisheries are the only phases 

 of the subject that officially concern the bureau, and it has continued 

 to endeavor, so far as its means would permit, to contribute to the 

 solution of the problems involved ; but it is futile to expect that much 

 can be done unless money and, particularly, trained and capable men 

 are provided for the purpose of determining facts and their prac- 

 tical and scientific implications. 



BIOLOGICAL LABORATORIES. 



The laboratory at Woods Hole was not operated during the sum- 

 mer of 1921 because of the limitation of funds, but its facilities were 



