Reproductive cycle of sea urchin Echinometra vanbrunti (Echinodermata: Echinoidea) from the Gulf of California

ABSTRACT

Echinometra vanbrunti is an echinoid found in abundance in the eastern Pacific, including the Gulf of California in Mexico. The aim of this study is to document its annual reproductive cycle from monthly sampling. Growth, condition and gonadosomatic index (GSI) were determined from morphometric data. Additionally, sex ratio and morphology of sea urchin gonads and their gametes were analysed by histology and microscopy. The growth pattern of E. vanbrunti was allometric. The monthly variations of GSI are explained by gonad condition and the gametogenesis cycle. An annual reproductive cycle was observed with higher GSI from July–September and the highest percentage of females and males in the mature stage in the same period. Gonad histology agreed with this single gametogenic cycle per year, and gametogenesis in males and females being highly synchronized in this species. Spawning period started in July and ended in November for both sexes.

KEYWORDS:

• Allometry
• sea urchin
• gonadosomatic index
• nutritive phagocytes
• gametes
• gonads

Acknowledgements

The authors are especially grateful to divers Ulises Becerra Lamadrid, Leopoldo Encinas and Fulgencio García Ochoa for their support during the sampling of organisms. The authors also appreciate the support of the Transmission Electron Microscopy Laboratory of the University of Sonora in the ultrastructure analysis of the gametes.

Ethic approval

The authors declare that all applicable national and institutional guidelines for sampling, care and experimental use of organisms for the study have been followed and all necessary approvals were obtained.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by Consejo Nacional de Ciencia y Tecnología [grant number 256753].