A whale of a puzzle

Press, 2 June 1981, Page 20

A whale of a puzzle

From ‘The Economist,’ London.

An expedition of scientists recently in the Antarctic encountered the largest concentration of marine animals ever recorded; a swarm of krill (shrimp-like creatures) weighing 10 million tonnes and covering an area of several square miles at depths from 60 'to 600 feet. The scientists also observed no fewer than 35 Russian 'trawlers fishing the krill. The vessels tried to dis- ■ guise what they were fishing uor, but there was little doubt : that it was krill. I Krill, which are the mam diet of whales, have been cited -as one of the world’s biggest unexploited food resources. There have been estimates putting the potential annual catch at more than twice the

70 million tonnes caught worldwide by all types of fishery today. But there are two problems.

One is the economics of krill fishing. The krill are remote from markets and in rough waters. Fishing them is en-ergy-intensive. Studies suggest they are uneconomic to harvest, except in marginal conditions. Evidently, the Russians do not share this view.

The other problem is how much krill you can safely catch without endangering the krill population. There are -many puzzles about the numbers of krill in the Antarctic. The krill themselves seem plentiful. They feed off plant plankton and there is a large supply of the basic nutrients that such plankton feed on. But the plant

plankton exist in remarkably small quantities. The recent scientific expedition set out to find answers to such puzzles. In all, there were 16 research vessels from 11 nations. The results from the different vessels have not yet been collated. But, on. first sight, it‘looks as if the expedition may have generated more puzzles than it solved. Dr Osmond Holm-Hansen, from the Scripps Institution of Oceanography in California, looked for krill’ for three months. In all that time, the 10 million-tonne swarm the Russians were fishing was the only concentration he encountered. In no other trawl did he catch more than half a bucket of krill. Scientists from some of the other ships had the same experience. Yet previous reports suggested that swarms of krill should be common.