Abstract
Mong-Fong Lee, Chun-Yen Lin, Chuan-Chin Chiao, and Chung-Cheng Lu (2016) The pharaoh cuttlefish, Sepia pharaonis, is one of the most important cephalopod fishery species in southeastern Asia. In the present study, we described their reproductive behavior and characterized their embryonic development. Sperm competition during mating was high in S. pharaonis; therefore, consort males always escorted their mates after pairing, although sneaker males were frequently observed. Their egg-laying behavior can be divided into three phases. Females first retracted and bent their arms into a fist-like posture to spawn eggs. They then extended their arms forward and used funnels to blow the spawning ground. Finally, they extended their arms again to deposit eggs onto appropriate substrata. Based on the characteristics of the embryos, a set of easily distinguished criteria was developed to define 30 stages of embryonic development. This classification scheme was consistent with that of S. officinalis. The present study provided an important basis for future investigations of the reproductive biology and aquaculture in the pharaoh cuttlefish, S. pharaonis.