178 



DISCOVERY REPORTS 



THE PROBABLE SEASONAL SUCCESSION 



The probable seasonal succession of the more important species within our area is 

 indicated in Figs. 77-9. For obvious reasons it has only been possible to include a few 

 of the leading forms in the charts. Two factors that tend to complicate the question 

 must be borne in mind : (i) while almost all the species reach their maximum during 

 the great spring increase, the time of this increase falls later in the year as one proceeds 



Fig. 77. The probable distribution of the dominant species over the area studied in late spring. 



southwards ; and (ii) transportation of the aftermath of the increase farther south by 

 surface currents may lead to an apparent increase later in the season in the more 

 northerly part of the region studied. Round South Georgia it seems fairly certain (cf. 

 p. 91) that the main increase takes place in late spring; in the Weddell Sea it appears 

 to take place at mid-season, and in the Bellingshausen Sea (doubtless in the far south 

 of the Weddell Sea also) even later — about the end of January. 



It should be realized that it is mainly to the more northerly parts of the region that 

 these remarks apply — the South Georgia area, the Scotia Sea, and Bransfield Strait. 

 Farther south seasonal data are scarce, owing to ice conditions, and it is probable that 



