PART VIII — AQUATIC ECOSYSTEMS 



tion and the oil is rich in vitamins. 

 The high proportion of unusable 

 chitin (in the shell of the krill) and 

 the rapid spoilage rate present tech- 

 nological problems. But these prob- 

 lems will be solved sooner or later, 

 and the commercial exploitation of 

 the antarctic krill might become a 

 realistic proposition in the future. 

 The Japanese have also shown some 

 interest; research into the exploita- 

 tion of the krill is now part of their 

 national oceanographic program, al- 

 though they have not done very much 

 so far. 



There are many other areas in 

 the world ocean where large concen- 

 trations of euphausids (of sizes 

 smaller than Euphausia sitperba) are 

 found, but the possibility of exploit- 

 ing them appears even more remote 

 than in the case of the antarctic 

 krill. 



The California Red Crab — An- 

 other form of zooplankton that has 

 attracted much attention is the Cali- 



fornia red crab, Pleuroncodes plan- 

 ipes. The animal has a pelagic 

 phase as well as a demersal (bottom- 

 living) phase. The relationships be- 

 tween the two are not well under- 

 stood, although the pelagic phase 

 appears to consist of relatively 

 younger individuals. It is possible 

 that the younger individuals can al- 

 ternate between the two phases. 



In their pelagic phase, the crabs 

 are capable of grazing on phyto- 

 plankton, particularly larger diatoms. 

 They appear in vast surface con- 

 centrations in waters off Baja Cali- 

 fornia and become an important item 

 in the diet of a variety of predators — 

 birds, tunas, and whales, among 

 others. The red crab in the demersal 

 phase also occurs in dense concen- 

 trations. 



Two species similar to the Cali- 

 fornia red crab are commercially 

 utilized in Chile, but their concen- 

 trations are found only on the bot- 



tom. The exploitation of the Califor- 

 nia red crab for manufacturing meal 

 for animal feeds has been suggested 

 by many scientists. No experiments 

 have been conducted, however, to 

 test the commercial feasibility of 

 catching and processing the crabs 

 for this purpose. 



In summary, the potential of zoo- 

 plankton as a source of animal pro- 

 tein material is great, and man will 

 go into this phase of exploitation of 

 living ocean resources sooner or later. 

 It is obvious that fisheries for zoo- 

 plankton would have to be developed 

 for specific forms of animals in 

 specific areas. However, even for the 

 species that appear most promising, 

 such as the antarctic krill or the 

 California red crab, much more work 

 is needed both in developing the 

 technology of catching and proc- 

 essing and in understanding the ecol- 

 ogy of the species involved, before 

 their commercial exploitation becomes 

 a reality. 



The Southern Oceans in the Production of Protein 



The antarctic oceans can be defined 

 for the purposes of this discussion 

 as the region between 60° and 65° S. 

 latitude in the three months of sum- 

 mer: January, February, and March. 

 Such an area subtends 3 million 

 nautical square miles of surface water. 

 During the other nine months of the 

 year, the weather and the extension 

 of sea-ice obliterate this area as ex- 

 ploitable for proteins by man. In- 

 clusion of sub-antarctic waters would 

 triple this area and extend its time 

 of usability at least two months 

 longer: December through April. 



This discussion involves only ani- 

 mal proteins. There are no sources 

 of plant proteins, unless some may 

 be obtainable from the giant kelp 

 Macrocystis. 



Protein Sources in the Antarctic 



Historically, this 3 to 9 million 

 square nautical miles of surface water, 

 and the water-column under the sur- 

 face, have been rich in biomass of 

 animal proteins. The waters in sum- 

 mer have teemed with invertebrates, 

 particularly the relatively small pe- 

 lagic shrimp Euphausia and related 

 genera. There have been many nest- 

 ing birds, particularly on the sub- 

 antarctic islands. Seals have been 

 abundant from the ice-pack north to 

 the sub-antarctic islands and elephant- 

 seals on the sub-antarctic islands. 

 Whales have been, in the past, the 

 most conspicuous form of animal 

 life, and in their abundance have 

 supplied the whaling industry with 

 the bulk of its raw materials, mostly 



oil, for fifty years, 1910-1960. The 

 supply of whales is practically gone 

 now, however. Fish have been found 

 sporadically in immense shoals, but 

 with such irregularity as to time and 

 place that no fishing industry has 

 grown up in antarctic and sub- 

 antarctic waters. 



Species of Current Interest — With 

 the demise of the whaling industry — 

 which can return, but only after 

 many years, and which never utilized 

 the animal proteins to the fullest 

 extent — and with the end, in the 

 nineteenth century of the fur-seal- 

 ing and elephant-sealing industry — 

 which could have supplied proteins, 

 but never did, only fur or oil — atten- 

 tion is now being directed toward 

 harvesting euphausid shrimp and 



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