H-13 



RESEARCH PROGRAMMES 



temperature, salinity, and water transparency with occasional nutrient analyses at interesting 

 discontinuities. The emphasis is on continuity of observations along meridional (or 

 near-meridional) sections. 



5. Structure of the water column. 



The success of the krill fishery depends upon knowledge of the distribution of krill in the 

 water column. Although empirical information is available from acoustic records, it will 

 eventually be necessary to understand the vertical migration of krill and, in particular, the 

 relationship between krill swarms and discontinuities in the water column. The major 

 discontinuity at the ice edge is the shallow halocline resulting from the melting of the ice, and 

 this should be studied. However, other discontinuities exist within the vertical range of krill, 

 and these should also be investigated. If possible, it would be desirable to track the seasonal 

 development and decay of these discontinuities. 



SELECTED REFERENCES 



ApolLONIO, S. 1961. The chlorophyll content of Arctic sea ice. Arctic, Vol 14, p 197-99. 



Bunt, J. S. and Lee, C. C. 1970. Seasonal primary production in Antarctic sea ice at McMurdo Sound in 



1967. Journal of Marine Research, Vol 28, p 304-20. 

 Ei^Sayed, S. Z. 1971. Dynamics of trophic relations in the Southern Ocean. /n: QUAM, L.ed. Research in 



the Antarctic. Washington, DC, American Association for the Advancement of Science, p 73-91 . 

 Ei^SayeD, S. Z. and Green, K. A. 1974. Use of remote sensing in the study of Antarctic marine 



resources. In: BOCK, P., BAKER, F. W. G. and RUTTENBERG, S. eds. Proceedings of the COSPAR 



Symposium on Approaches to Earth Survey Problems through the Use of Space Techniques. Berlin, 



Akademie-Verlag, p 47-63. 

 McROY, C. P. and GOERING, J. J. 1974. The influence on the primary productivity of the Bering Sea. /n: 



HOOD, D. W. and KELLEY, E. J. eds. Oceanography of the Bering Sea. Fairbanks, University of Alaska, 



Institute of Marine Science, p 403-21. 

 Mf.GURO, H. 1962. Plankton ice in the Antarctic Ocean. Antarctic Record, \ol 14, p 1192-99. 



2.4 KriU 



2.4.1 Introduction 



It has been well known for many years that vast quantities of krill exist in Antarctic 

 waters, but interest in their commercial exploitation did not arise until the early 1960's. Baleen 

 whale stocks had declined as a consequence of overharvesting, which meant that grazing 

 pressure on krill by these consumers was reduced. During the same period, stocks of more 

 famiUar aquatic species, taken in traditional fishing grounds, were becoming fully exploited. 

 Reduced opportunities for increasing harvest from other areas has focused attention on the 

 potential of other food sources and, in particular, on Antarctic krill. 



Many computations have been made of production and standing stock of this pelagic 

 euphausiid (McQuillan, 1962: Shevtsov, 1963: Jonsgard and Ruud, 1964; Mackintosh, 1966, 

 1970; Lyubimova and others, 1973; Omura, 1973; Fischer, 1974; Tomo and Marschoff, 1974; 

 Everson, 1976) and most estimates of an annual harvestable yield range from 100 to 150 million 

 tons. These figures have been derived using a variety of approaches including the consumption 

 of past and present stocks of whales (based on their residence time in Antarctic waters, 

 volume of stomach contents and energy requirements), consumption by other vertebrate 



