Krill (Antarctic Krill)
 
 
The krill exists in quantity and is a principal food source for many marine animals, which makes it a key species of the Antarctic marine ecosystem. It has also been a fishing target that accounts for up to 500,000 tons per year.

Although the existing krill population is estimated as a few hundred million tons, it is said that fishing in certain areas may affect predators such as penguins since the population is susceptible to yearly changes. Maximum length: 60mm. Longevity: 6-7 years.
 
Source: Nankyoku no kagaku I Sousetsu.National Institute of Polar Research.1991
  (Science in Antarctica 1 Introduction ;Japanese)