OCEA EDUCTION 



The Antarctic Krill — There is 

 general agreement, among scientists, 

 that one of the most realistic targets 

 would be the exploitation of the 

 enormous resources of antarctic eu- 

 phausids (krills), particularly Eu- 

 phausia superba. The species occurs 

 only in the antarctic (i.e., south of 

 the Antarctic Convergence), and is 

 particularly abundant in waters off 

 South Georgia and around Antarc- 

 tica near the edge of the pack-ice. 

 Vertically, it occurs to a depth of 

 several hundred meters at larval 

 stages, but adults are often found in 

 dense concentrations in the surface 

 layer, forming patches of various 

 sizes and shapes. Sexual maturity is 

 reached in about two years, with an 

 average size of 50 millimeters. 



The krill is the most important 

 food of whalebone whales migrating 

 into the antarctic in the summer; it 

 very often constitutes the entire 

 stomach contents of whalebone 

 whales caught there. Many other an- 

 imals, including seals, birds, and 

 fishes, also depend on the krill for 

 subsistence. (See Figure VIII— 6) 



Although no reliable measurements 

 are available, the total annual pro- 

 duction of Euphausia superba might 

 be as much as one-half of the total 

 production at the level of herbivores. 

 Based on the estimated amount of the 

 krill eaten by whalebone whales in 

 the antarctic when the whale stocks 

 were large (they have been reduced 

 greatly by overexploitation), the po- 

 tential yield of Euphausia superba, 

 when fully exploited, might be as 

 high as 50 to 100 million metric tons, 

 or roughly equal to the present total 

 fishery yield from the entire world 

 ocean. 



For some years, the Russians have 

 been conducting experiments in the 

 antarctic to develop methods of 

 catching and processing the krill. 

 They have used large surface trawls 

 and pumps to collect the krill, which 

 have then been processed into meal 

 or paste, and oil. The krill meal has 

 a reasonably high protein concentra- 



Figure VII 1-6 — AN ANTARCTIC FOOD CHAIN 



The diagram shows some of the major food chains found in the antarctic. Note 

 that the chain to the whalebone whales is relatively direct; the organic material 

 synthesized by the phytoplankton passes through only one intermediate animal, 

 the krill (Euphausia superba), before becoming transformed into whale flesh. 

 This direct change of plankton is extraordinary and a notable exception to the 

 normally low efficiency of the conversion of organic material from the sea. 



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