Summary
Embryos released by gravid females of Antarctic krill (Euphausia superba Dana) at the Port of Nagoya Public Aquarium, Japan were incubated in the laboratory to determine the development time and hatching success of embryos at 2.1, 1.7, 1.2, 0.6, 0.1, 0.8 and 2.4C. Embryo development time was significantly related to temperature, and could be expressed either in an exponential model or Be¡ le´ hradek’s equation. D ¼ 2:7 e0:27T þ 2:92 D ¼ 65:3 T þ 8:8 ð Þ1:13 The Be¡ le´ hradek’s equation was compared with previous studies, and also with those on other marine crustaceans. The curve calculated by this equation was similar to those for other arctic zooplankton species. Hatching success ranged from 7 to 58%, and varied between each gravid female. The physical condition of gravid females may affect the embryo quality and the hatching success. The factors that determine embryo development time and hatching success are discussed by comparing the data with those from previous studies performed on euphausiids and other marine crustaceans.