Study on biological zero and effective accumulated temperature of embryonic development and gonadal development of cuttlefish Sepia pharaonis

Research on the aquaculture of cephalopods has emerged in the last 30 years. Compared to other animals, limited information exists on the fundamental biology of cephalopods, particularly regarding their gonadal and embryonic development. Detailed investigation into their reproduction and development could provide a solid practical basis for understanding their methods of reproduction and reproductive patterns for enhancing artificial-seeding cultivation techniques. Therefore, this study utilised the second generation (F2) of cultured cuttlefish, Sepia pharaonis Ehrenberg, 1831, controlling the hatching temperature of fertilised eggs and recording data at various stages of gonadal development. We calculated the biological zero, the effective cumulative temperature, the temperature coefficient for embryonic development and the effective cumulative temperature for gonadal development. The results indicated that the biological zero and effective cumulative temperature for embryonic development of S. pharaonis were 7.46 and 434.87 °C·d, respectively, with the optimal temperature range for embryonic development being 24–27 °C. The effective cumulative temperature for gonadal development was 853.04 ± 57.51 °C·d. This study provides essential information on the biological zeros and effective cumulative temperatures for both embryonic and gonadal development of S. pharaonis, offering significant practical information and a theoretical basis for future large-scale artificial cultivation of this species.