Effect of temperature increase on fertilization, embryonic development and larval survival of the sea urchin Toxopneustes roseus in the Mexican south Pacific.

ABSTRACT

Toxopneustes roseus performs a key role in the eastern tropical Pacific as a strategic herbivore and bioturbation promoter. We evaluated the effect of temperature on the fertilization success, embryonic development and larval survival of T. roseus under laboratory conditions, to understand how the increase in ocean temperature could affect it in a global warming. The highest percentage of fertilization occurred in gametes that were exposed to 30 °C, and a significant negative effect of 32 °C was evidenced by the lowest percentage. There was also a deleterious effect in embryos exposed to 32 °C, resulting in an abnormal development at all the time points. The highest percentage of larval survival occurred at 30 °C, while the lowest percentage occurred at 32 °C. The results suggest that T. roseus probably lives near its upper thermal limit, and future ocean warming could threaten the permanence of the species in the eastern tropical Pacific, or at least lead to contraction or fragmentation of its range limits. Therefore if sea temperature rises globally, it could cause the disappearance of these populations that are living at the edge of their thermal tolerance, but for other populations located in more temperate latitudes, it could propitiate favorable conditions for fertilization and survival of embryos and larvae.