6 



PROCEEDINGS OF THE NATIONAL MUSEUM 



the zooplankton in the upper 1000 m, where differences in volumes 

 within the same depth intervals frequently are much larger. 



The mean volumes for each of the three depth intervals can be com- 

 pared to those we obtained in the northeastern Atlantic between 30° 

 and 40°N (Grice and Hulsemann, 1965). For the depth intervals 

 2000-1000, 3000-2000, and 4000-3000 m the mean zooplankton vol- 

 ume for the Indian Ocean were .004, .002, and .002 cc/m^, respec- 

 tively and for the Atlantic Ocean, .005, .002, and .001 cc/m^, respec- 

 tively. These data are certainly similar and indicate how small 



0.015 



0.010 



0.005 



2000- 1000 M 

 3000- 2000 M 

 4000-3000 M 



I 



328 330 332 334 336 338 340 342 344 347 349 355 



STATION 



Figure 2. — Displacement volumes of the total zooplankton (A) and number of adult 

 copepods excluding contaminant specimens (B). 



the zooplankton population is at great depths in the northeastern 

 Atlantic and western Indian Oceans. 



CoPEPOD ABUNDANCE. — The number of adult copepods per 100 

 cubic meter computed from the collections taken with the NV net are 

 presented in figure 2(B). In general, the trends in copepod abundance 

 are similar to those found for the total zooplankton. With but one 

 exception the numbers of copepods within the 2000-1000 m iaterval 

 were much larger than in the intervals below 2000 meters. In no 

 case, however, did the numerical abundance exceed one copepod per 



