Krill catch increased rapidly. In the 1980s, a few additional nations started operating in the area: Poland, Chile, and South Korea. Their catches amounted to a few thousand tonnes annually; the lion's share went to the Soviet Union, followed by Japan. A peak in krill harvest was reached in 1982 with a total production of over 528,000 tonnes, of which the Soviet Union produced 93%. In the following two years, production declined. It is unclear whether this was due to the discovery of fluorides in the krill's exoskeleton or to marketing problems. The trade recovered quickly, though, and reached more than 400,000 tonnes again in 1987.