PEOGRESS IN BIOLOGICAL INQUIRIES, 19 29 1073 



As in previous years, the division has a<>ain been fortunate in 

 receiving whole-hearted and generous cooperation from various 

 States and private agencies, thus materially increasing its investiga- 

 tions in both extent and effectiveness. Such cooperation, which is 

 gratefully acknowledged, is in most cases mentioned in connection 

 with the various investigations in the following pages. The follow- 

 ing progress reports covering the more important investigations 

 conducted by the division during the calendar year 1929 were pre- 

 pared in the main by the investigators in charge of the various 

 projects. 



NORTH AND MIDDLE ATLANTIC FISHERY INVESTIGATIONS 



Some of the countrj^'s most productive fisheries are prosecuted in 

 the waters along the Atlantic seaboard from Maine to the Virginia 

 capes. Exclusive of shellfish, the annual harvest gives a gross return 

 of nearly $24,000,000 to the commercial fishermen. 



Initial steps in studies of marine fisheries are to learn the life 

 histories of the fishes themselves, their movements, the specific peculi- 

 arities in birth rate and mortality that regulate their abundance, 

 but investigations soon reach the point where further understanding 

 requires intimate knowledge of the significant physical and biologi- 

 cal conditions in the sea. 



OCEANOGRAPHIG STUDIES 



A consolidation of the several investigating staffs in this area has 

 made it possible to initiate in a small way an oceanographic program 

 in accompaniment with the various fishery investigations. The co- 

 operation of the Museum of Comparative Zoology at Harvard Uni- 

 versity in providing laboratory and librai-y facilities for the major 

 portion of the staff engaged in these studies has been of prime im- 

 portance in making this arrangement feasible, and the advice of 

 Dr. Henry B. Bigelow, of the museum staff at the Museum of Com- 

 parative Zoology, has been largely responsible for the planning of 

 the oceanographic projects. 



The bulk of oceanographic observations were made during five 

 cruises of the Alho.tr oss II in connection with the mackerel investi- 

 gations, the principal object being to estimate the success of mackerel 

 spawning. Two other cruises were made in connection with the cod 

 investigations. The principal object of the trip in February and 

 March, was to determine conditions in the wintering grounds of the 

 codfish off New York and New Jersey. A few observations also re- 

 sulted from a cod-tagging trip to Nantucket Shoals in June. (See 

 Table 1.) As a result, we have temperature and salinity surveys 

 of the waters overlying the continental shelf between Cape Cod and 

 North Carolina for February, April, and July; zooplankton surveys 

 of surface and deep levels for April, May- June, and July; and sur- 

 face phytoplankton surveys for the same months. In addition, there 

 are two series of collections for the study of diurnal vertical 

 migrations of zooplankton. 



The fish eggs and larvae of these cruises have been partially ex- 

 amined, and the zooplankton of all but the last cruise has been 



