Observations on embryos and embryonic development from an egg mass of the jumbo squid Dosidicus gigas spawned under captive conditions

Abstract

Egg masses were spawned by a jumbo squid Dosidicus gigas (mantle length 37.5 cm) held in a tank (500 L) on board the R/V Kaiyo Maru during a joint Japan-Peru cruise in Peruvian waters during December 2011– February 2012. Part of an egg mass was collected and incubated in an aquarium (10 L) maintained at 20 °C. The eggs had a unique jelly envelope surrounding the chorion. The diameter of the jelly envelope was more than twice the diameter of chorion. It remained clearly visible until the embryos reached developmental stage 18. Most of the eggs were fertilized and hatched (Stage 30) 6.5 days after spawning at 20 °C.