DISTRIBUTION OF ANTARCTIC M ACROPLANKTON 



145 



Orkney Islands various stations have been taken, many of which were at the edge of the 

 Weddell Sea pack-ice. 



The three surveys of the Bransfield Strait were taken in February 1928-9, November 

 1929-30, and December 1930-1 (Figs. 15-17). It will not be necessary here to tabulate 

 the numbers of each species taken at the different stations. If the catches of Euphausia 

 superba are disregarded it may be said that every sample which has been taken from the 

 Bransfield Strait has been an extremely small one, and if one sample ( WS 393), which 

 contained the exceptional quantity of 520 Metridia, is also disregarded, the largest catch 

 from the three surveys contained only 300 organisms. It is known that the south side of 

 the Bransfield Strait is occupied by Weddell Sea water, and the north side by water from 

 the Bellingshausen Sea. The distribution of the macroplankton, however, does not 

 appear to differ very much in different parts of the Strait, and with such small samples, 

 many of them containing only twenty or thirty organisms, it is very difficult to establish 

 a reliable correlation between the local hydrological conditions and the distribution of 

 the macroplankton. 



Between the South Shetland Islands and the South Orkney Islands there are no 

 straight lines of stations, and usually only two or three stations have been taken at a 

 time in this region, but in the 1930-1 season the 'Discovery II' worked eight con- 

 secutive stations in December along the ice-edge from near the South Orkneys towards 

 the Bransfield Strait (Sts. 534-41, Fig. 14), and eight more in roughly the same 

 position in March (Sts. 637-44, Fig- H)- Trie numbers of the principal species at these 

 stations are shown in Table XIV. 



Table XIV. Shetland-Orkney region 



It will be seen from Fig. 14 that in both these lines the more westerly stations are 

 closer together than the others. 



This is still a definitely thin plankton, but it is richer than in the Bransfield Strait and 

 much more variable. There are considerable fluctuations both in the total number of 



