Desarrollo de la Antártica

R. B. Thomson ¡ THE DEVELOPMENT OF LIVING RESOURCES .•• gence and the tAntarctíc continent in giant shoals or swarms up to km long and several hundred metres wide. These concentrations have a density of about 15 kg per cubie metre; thus, the Iargest swarms eontain about one hundred thousand tons of krill. Whales have fed almost exclusively on krill for centuries thus the amount of krill has possibly been contained at a similar level during this time. In recent years, man's harvesting of whales which has loo to a vast decrease in their numbers suggests that the po,pulation of krill must now be increasing very rapidly. Estimates of the standing stock of Antarctic hill are in tlhe order of eight hundred to five thousand million lOns providing a potential annual yield of at least one hundred million tons, nearly twice the present total annual worJd catch of aquatic resources. It eould rwell be of benefit to the ecologieal balance of the Southern Oeean if t:he krill populatíon could be con· trolled by a new factor sueh as harvesting as food for mano When one eonsiders tlhe exeeptional growth rate and size of whales it :;eems obvious that krill are an impressive source of food for whales. So, why not for man? T'he commercial utilization of krill was first studied by New Zc:l;' iand scientists in 196&. A sample "catch" of 600 lb was collected at a position B6°59' W, 66°58' S using a 10 foot lsaacs Kidd midwater trawl for four minutes at about three knot5. The most striking im– pression of rhe sample, even when frozen at minus 30°C was the intense odour of 5eafresh crustaceans, such as crabs, shrimps and the mustard of crayfish. An analysis of the krill material showed: - moisture 77.8%, erude protein 15.5% and fat 4.9%. The ratio oE soluble protein nitrogen to total pwtein nitrogen was 52.6%. Later wo:t1k was carried out to determine the aminoacid eomposítion of the soluble protein fraetion. This was found to be high in essential ami– noacids (sueh as arginine, lysine, lincine and phenylalanine) . Work was concentrated 011 utilizing the kríll material as a flavou– ring agent in sea foods to enhance the palatability of Eish lacking a characteristic or attractive flavour. The products successfully deve– loped included a canned puree, an essence, and a freeze dried powder. !These were found well suited for home cooking and in industrial pre– parations of fish products. The Soviets have since marketed krilI-butter, krill creese spreads, and a krill paste at about one dollar per pound. They claim mediCi– nal propertíes for this paste, reporting a 60% increase in the number of stomach ulcer patients who were cured by thera,peutic rather than surgical means after being fed rhe paste.