a potential but remote food resource. We acknowledge that as 

 members of the world's greatest food exporting nation, we stand in 

 no present need for krill and all that it may promise. As fishery 

 technologists, however, from a nation that is a major importer of 

 fish and fish products, we cannot ignore the activities of other na- 

 tions. 



Mature krill that do not engage in deep vertical migrations are 

 swept to the north. The vertical distribution of adult krill is about 

 90% between the surface and 100 m. Daily, vertical migrations do 

 occur with daytime concentrations occurring between 10 and 40 m, 

 as opposed to nighttime concentrations located from the surface to 

 a depth of 10 m (Marr 1962). 



THE KRILL RESOURCE 



The Norwegian noun "kril" means "young fry of fish" but is 

 generally interpreted to mean "whale food." This term was used 

 by Norwegian whalers originally to apply to a particular shrimp- 

 like euphausid known scientifically as Meganyctiphanes 

 norvegicus that is common to North Atlantic waters. It was the 

 basic food of baleen whales that were hunted in the 1800's. Shortly 

 after the 1900's, whaling interests shifted to Antarctic waters where 

 baleen whales fed upon related euphausids, chief among which 

 was Euphausia superba which was later dubbed "krill." There is 

 no known reason for the extra "1" in krill. 



The South Atlantic krill differs from its North Atlantic relative 

 in that it is larger and feeds upon phytoplankton chiefly in the form 

 of algae, principally diatoms. The northern krill reverses the 

 feeding role and preys upon animal life in the form of copepods 

 although both can, under certain circumstances, reverse their 

 roles. 



For the purposes of this report, the term "krill" will mean 

 Euphausia superba that is common to Antarctic waters 2 . Krill have 

 transparent bodies and are highly luminescent at night as they bear 

 light-producing organs on the outer side of the eyestalk, on the 

 underside of the first four abdominal segments, and two pairs 

 under the thorax (Hardy 1967). The carapace is enlarged and con- 

 nected with all the segments of the thorax except the last. The eyes 

 are mounted on the eyestalks, and the heart and gills are in the 

 thorax. Both sexes have well developed swimmerets. In the female 

 the egg pouch is located at the rear on the thorax. They are 3 to 6 

 cm long, and the color of living specimens is pink to brilliant red. 

 (In dense swarms, they give the appearance of a sea of tomato 

 soup.) Their weight ranges from 0.3 to 1.2 g. 



Distribution 



While krill is circumpolar in distribution, its concentration is 

 asymmetric. Figure 1 shows a much heavier concentration in the 

 polar Atlantic than in the polar Indian or Pacific Oceans. 

 Historically, the greatest concentrations of baleen whales has 

 always been in the Atlantic sector between long. 60°W and 30°E, 

 and it is natural that the concentration of whales would be in pro- 

 portion to the amount of food that they could obtain for the 

 limited time they feed upon krill before the whales disperse. 



The reasons for the concentration of krill are not yet completely 

 understood. Soviet scientists have shown that young and mature 

 krill are seldom found together (Makarov 1970). Usually mature 

 krill are found to the north, and the young are found to the south. 

 The dividing point between young and mature is placed at 1 to 1.5 

 yr of age, and it is the young which comprise most of the stock. 

 The Soviets hold that the separation of the young and mature krill 

 is due to a seasonal migration which is occasioned by the difference 

 in horizontal movement. They maintain that the young are carried 

 to the south as a result of their vertical migration to the depths. 



; Other species of Antarctic euphausids are: cryslalloqjhias, frigida, hanseni, 

 longiroslris. lucens, similis, spinifera, triacantha, and vallentini. 



Magnitude and Potential Yield 



Estimates of the magnitude of the stock and its potential yield 

 vary considerably because E. superba has a remarkably long life 

 (25-48 mo) for a euphausid. The lack of reliable data on the pro- 

 ductivity of Antarctic krill makes estimations of magnitude of 

 stocks and annual yields debatable. For example, Langunov et al. 

 (1973) placed the potential annual catch at 100 million t (metric 

 tons), yet Gulland (1970) estimated it to be 200 million t. Using a 1 

 yr life span in relation to the standing crop biomass, Gulland arriv- 

 ed at approximately a 75 million t annual production. Allen (1971) 

 revised Gulland's estimate by assuming a 4-yr life span of E. super- 

 ba and claimed that the annual production figure should be 150 

 million t. Not all parts of the Antarctic where krill occur are as 

 readily exploitable as the Atlantic sector, thus tending to make the 

 total potential yield figure somewhat uncertain. A conservative 

 estimate would place the annual harvestable yield at several tens of 

 millions of metric tons. 



Harvesting Feasibility 



As used here, the term "harvesting feasibility" refers solely to 

 the presence of concentrations of krill that would make a krill 

 fishery successful in respect to rate and size of catch. It is a 

 peculiarity of krill that they are marked by a very strong habit of 

 concentrating in dense masses, so dense that they impart a 

 discoloration to the water intense enough to be sensed by remote 

 satellites (El Sayed 1975). The unexplained phenomenon of dense 

 concentrations is further complicated by the fact that individuals in 

 a particular subdivision of a patch called a "swarm" possess the 

 same degree of maturity. One large patch of krill may be composed 

 of several swarms of krill, and each swarm will consist entirely of 

 either adults or juveniles with very little admixture. 



The density of the patches of swarming krill are not evenly 

 distributed in the water column. Some may easily be spotted 

 visually near the surface, and others may be located as deep as 100 

 m by electronic sensing devices. Regardless of their depth, it is 

 agreed by both scientists and practical fishermen who have been 

 observers of the habits of krill, that the concentrations would sup- 

 port a high rate and volume of catch. 



Political and International Pressures 



For years Argentina, Australia, Chile, France, Great Britain, New 

 Zealand, and Norway have made territorial claims in Antarctica. 

 Many nations (U.S.A., U.S.S.R., Japan, Sweden, Belgium, and 

 Federal Republic of Germany) have made Antarctic explorations 

 without lodging such territorial claims. The United States, in spite of 

 the years of exploration by Admiral Richard Byrd and others, has 

 chosen not to make such demands in agreement with the policy an- 

 nounced by Secretary of State Charles Evans Hughes in 1924: "It is 

 the opinion of this Department that the discovery of lands unknown 

 to civilization, even when coupled with a formal talcing of posses- 

 sion, does not support a valid claim of sovereignty, unless the 

 discovery is followed by an actual settlement of the discovered 



