460 U. S. BUREAU OF FISHERIES 



New Jersey, young spot grow more rapidly than those which remain 

 in the South. 



The interdependence of northern and southern stocks of spot is 

 further evidenced by facts pointing toward a southward migration 

 of young spot in the autumn, for their disappearance at that season 

 from New Jersey waters is accompanied by a sudden increase in 

 average length of the stock of spot in North Carolina, due doubtless 

 to the addition of the faster-growing northern spot to the North 

 Carolina population. This view is supported by the winter recap- 

 ture in North Carolina of a young spot which had been tagged in 

 New Jersey the previous October. 



As in 1929 and 1930, large collections of squeteague eggs were made 

 in June, 1931, near the mouth of Delaware Bay, but no larva? were 

 taken. Although numerous juveniles were taken subsequently, they 

 appeared too late to have resulted from the spawning noted. It 

 remains an open question whether these juveniles resulted from local 

 spawning which escaped observation or whether they, like the spot, 

 migrated while still very small from the southern grounds where 

 larvae as well as eggs have been captured. 



OCEANOGRAPHIC STUDIES 



As more and more of the fluctuations of our fisheries are traced to 

 variations from year to year in the survival of the early stages of 

 various species, the discovery of the causes of this variation becomes 

 more and more urgent. This involves a greater understanding of 

 oceanographical conditions than has yet been attained. Although 

 the bureau does not have the means to enter into this field at present, 

 it has been fortunate in having the study of the physical ocean- 

 ography and the plankton of the waters overlying the continental 

 shelf between Cape Cod and Cape Hatteras undertaken by Dr. Henry 

 B. Bigelow, director of the Woods Hole Oceanographic Institution, 

 and Mary Sears. 



Much of the material necessary for this study has been accumu- 

 lated on cruises made by the Albatross II in that area for investiga- 

 tion of the spawning of the mackerel. Additional data and collec- 

 tions are being secured by the research ship Atlantis of the Woods 

 Hole Oceanographic Institution to supplement collections already 

 made. 



A resume of oceanographic work done by the Albatross II during 

 1931 appears in the accompanying table. 



