Statolith growth of juvenile oval squid Sepioteuthislessoniana (Cephalopoda: Loliginidae) with special reference to ambient thermal condition

Abstract

Growth of the statolith of the oval squid, Sepioteuthis lessoniana, was observed in captive juveniles up to 45 days post-hatching. Juveniles were raised at different water temperatures (20°C, 25°C, 30°C, including switching from 20 to 25°C regimes). Statolith size was strongly correlated with squid body size regardless of age, and these relationships were positively correlated with ambient thermal condition. At 30 days post-hatch, mantle length and total length of statolith were 8.70±0.15 mm and 636.4±12.5 µm, respectively, in the 20°C group and 12.48±0.78 mm and 730.4±8.8 µm in the 30°C group. It was revealed that oval squid statoliths grew in a circular manner from the centre and were affected by ambient temperature.

Keywords:

• Growth
• juvenile
• oval squid
• statolith
• temperature

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark

Acknowledgements

We acknowledge F.E. Anderson for reviewing the manuscript. We also thank T. Higa for his kind cooperation for squid egg collection. Y. Oshima, S. Kobayashi and C. Sugimoto are thanked for their cooperation of rearing squid. This study was partially supported by the 21st Century COE program of the University of the Ryukyus, for which we are most grateful.

Notes

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark