Embryonic development of Loligo gahi and modeling of hatching frequency distributions in Patagonia

The embryonic phase of a cephalopod species may represent an important part of its life cycle, especially when it inhabits low temperature waters. Loligo gahi is the second most important loliginid squid in captures worldwide and is abundant in cold waters of the Patagonian shelf. No information has been published on this species' embryogenesis. A scale of embryonic development was established for the species; the embryos were incubated at six different temperature regimes and the lengths of development from different stages of embryonic development to hatching were recorded. The embryonic development of L. gahi was normal within the range of 5°–20°C, and stopped at temperature regimes of 4°C and 23°C. The daily accumulated temperature (DAT) required for development from fertilization to hatching was estimated to be 617–789°C d. Annual seasons of low (fall to winter) and high (spring to summer) hatching frequency were observed in numerical projections of hatching frequency distribution for coastal locations of the Patagonian coast.