PROGRESS IX BIOLOGICAL INQUIRIES, 1923. 17 



During the year Mr. Hildebrand visited several localities in the 

 South in an advisory capacity, ottering suggestions for the best use 

 of top minnows for the control of malaria and for the propagation 

 of these fish for distribution. 



OCEANOGRAPHIG WORK, 



During the fiscal year 1923 laboratory work on the collections made 

 in the hydrographic and biological survey of Chesapeake Bay was 

 inaugurated, the field work in the main having been completed early 

 in June, 1922. The special collections have been segregated and as- 

 signed for study by specialists in the National Museum and biologists 

 in various parts of the United States and Canada, and a comprehen- 

 sive report on the fish and fisheries of the region is well advanced. 

 The data relating to the physical and chemical features have been 

 compiled, and a report on this phase of the investigation is also well 

 under way. 



In this investigation the bureau has received cooperation and as- 

 sistance from the United States Geological Survey in the determina- 

 tion of the salinities of the water, and from these results most of the 

 densities have been calculated. The Geological Survey has also fur- 

 nished important information concerning the average amount of 

 fresh water that drains into Chesapeake Bay, and this, together with 

 valuable information prepared by the United States Coast and 

 Geodetic Survey as to the total area, areas of cross sections, and 

 volume of sea water entering the bay, will have an important bear- 

 ing on the study of the movements of the water and the organisms 

 contained in the water. The United States Weather Bureau has 

 cooperated by furnishing information on the daily precipitation dur- 

 ing the last few years in drainage basins that feed Chesapeake Bay. 

 These important data have been found very valuable in the study 

 of the variations in position of the water layers of different density 

 in the bay. 



The survey of Chesapeake Bay was begun in 1912 by Lewis Rad- 

 cliffe and William W. Welsh primarily for the study of the Clupeidse. 

 The work was later extended to include the general fauna and flora 

 of the bay, with the exception of the birds and the higher plants. Dr. 

 R. P. Cowles, of Johns Hopkins University, undertook the super- 

 vision of the work and personally conducted numerous cruises on the 

 bay during 1920 to 1922. William C. Schroeder made extensive col- 

 lections of fishes and obtained many data on the commercial status 

 of the fisheries of the region. The fisheries steamer Fish Hawk was 

 used in making the survey. 



To supply fundamental data for the elucidation of oyster-cultural 

 problems, especially the failure of the set. Dr. Paul S. Galtsoff, 

 naturalist on the fisheries steamer Albatross^ has been conducting a 

 hydrographic and microbiologic survey of Long Island Sound and 

 adjacent waters. The program included a series of Richter and 

 Megretti-zambra reversing thermometer readings and Eckman cur- 

 rent-meter readings, salinity and dissolved oxygen titrations, coloro- 

 metric hydrogen-ion determinations, color and transparency deter- 

 miniations, qualitative and quantitative plankton studies, and quanti- 

 tative bacteriological tests. Fourteen cruises were made with the 



