Embryonic development and hatchlings of <i>Illex argentinus</i> derived from artificial fertilization

Abstract

The embryonic and early post-hatching development of artificially fertilized eggs of Illex argentinus was observed at several temperatures from 8.5 to 23.2°C. During the fertilization procedure, oviducal gland jelly was added to eggs (about 1.0 mm long). Chorion expansion began 20 minutes after fertilization and continued throughout embryonic development. Before hatching, the chorion diameter measured more than 2.5 mm. Developmental stages were described on the basis of morphological features. Most hatchlings from the least disturbed eggs had well-developed ink sacs, fins, extensible probosces and buccal masses. The mantle length of hatchlings was approximately 1.6 mm. Comparisons are made with embryos and hatchlings of other ommastrephid squid, Illex species and Todarodes pacificus.