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

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.

Automated summary

The study documented the annual reproductive cycle of Echinometra vanbrunti through monthly sampling, revealing a clear reproductive pattern with peak sexual maturity and synchronized gametogenesis in July-September each year. The histology of gonads and the morphology of gametes also supported this single annual gametogenic cycle.