Reproduction of the Diadematidae sea urchin Centrostephanus rodgersii in a recently colonized area of northern New Zealand

Abstract

Reproduction of the sea urchin Centrostephanus rodgersii at the Mokohinau Islands (northeast New Zealand) was studied in terms of the gametogenetic cycle and sex ratio, and larval range of thermal tolerance was determined. A comparison with the reproductive patterns in populations located in New South Wales (NSW), the historical range of the species, and Tasmania, where the species has only recently arrived (≈ 50–60 years ago), was made. Results indicate that C. rodgersii in New Zealand is capable of growing gonads, completing a gametogenetic cycle and producing viable gametes. The timing of this process is similar to the population in Sydney (central NSW), where spawning is probably triggered by the winter solstice and lasts from July to September. The sex ratio was skewed towards females (1.6 females for each male), which may be indicative of the recent arrival of the species in New Zealand. Larvae obtained from this population were able to develop at a measurable rate after 72 h only between 16°C and 25°C. Ambient temperatures during spawning at the Mokohinau Islands (15.7–16.8°C) appear to be at the lower end of the range of temperatures suitable for early larval development.

Keywords:

• Centrostephanus rodgersii
• New Zealand
• gametogenesis
• reproduction
• larvae
• climate change
• range expansion

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

The authors wish to thank the staff at the Portobello Marine Laboratory in Dunedin (Otago, New Zealand), and the staff at the Leigh Marine Laboratory in Leigh (Northland, New Zealand) for assistance while running experiments, Jake Lamare for helping with the dissections of the sea urchins and collection of biometric data, Colleen and Myles Hayward for the hospitality and the Goat Island Dive Centre for collecting the sea urchins for the histological analyses. This research was supported by a student research grant of the New Zealand Marine Sciences Society.

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