Spawning behaviour and early development of the Antarctic krill, Euphausia superba DANA, observed on board R. V. KAIYO MARU in 1979/80

Abstract

During the cruise of the Antarctic Expedition R. V. KAIYO MARU in 1979-80,the rearing of the Antarctic krill, Euphausia superba DANA, was conducted in order to observe the spawning behaviour and the early development. The krills which were collected by a 0-36m oblique tow using the KOC-A net at the position of 64°-45.5'S, 114°-04.0'E on January 24,1980 were reared at 0.4℃. The time needed for completion of spawning was about 50 minutes. Spawning behaviour was photographed and sketched. The total numbers of spawned eggs counted soon after the spawning in six females were in a range of 1140-1688. Nauplii began to hatch out after seven days of spawning. The hatchability varied with the rearing density. Twenty five nauplii developed to the metanauplius stage after 25 days of spawning.