  Seawater temperature rise is damaging coral reef ecosystems. There is growing
evidence for the negative impact of rising temperatures on the survival of
adult corals and their reproductive success. However, the effect of elevated
temperatures on gametes remains scarcely studied. Here we tested the effect of
the thermal priming of gametes on the fertilization success in experimentally
tested populations of Acropora cytherea corals in French Polynesia. As
expected, a temperature of 30 {\textdegree}C (ambient +3 {\textdegree}C)
reduces coral fertilization success. However, the thermal exposure of gametes
to 30 {\textdegree}C after their release in seawater prior to fertilization
limited fertilization failure, with a greater impact of oocytes in comparison
to sperm. This temperature is similar to temperatures observed in nature under
the changing climate. Our findings imply that the thermal priming of early life
stages, such as gametes may play a role in maintaining the coral fertilization
success in spite of increasing seawater temperature.
