Effects of temperature on embryonic development and paralarval behavior of the neon flying squid Ommastrephes bartramii

Abstract

Studies on the relationships between the early life stages of the neon flying squid Ommastrephes bartramii and oceanographic conditions are essential for understanding the spatial and temporal distribution patterns of this ecologically and economically important species. In this study, O. bartramii eggs were artificially fertilized and incubated at temperatures found in its known distribution range (16−26°C). Complete organogenesis with normal successive cleavage and the distinct continuity of morphological features was limited to between 18 and 25°C. Experimental rearing, cruise-collected specimens, and oceanographic data confirmed that the optimal temperature range for paralarval survival around Hawaii is 18 to 25°C. Embryos reared at 16°C showed abnormal organogenesis; however, normal development resumed when the embryos were transferred to 22 or 24°C after blastoderm formation. Hatchlings showed a variety of swimming behaviors, which may allow squid to regulate their thermal distribution in the wild. Furthermore, ball formation and associated chromatophore expansion might represent an apo sematic adaptation to imitate unpalatable prey. This study highlights the flexible strategy of O. bartramii embryo development and illustrates how information on paralarval behavior and oceanographic data (sea surface temperature) may be combined to improve our understanding of the factors that influence the survival of this species.