Predicting the effects of climate change on the fertility of aquatic animals using a meta-analytic approach

Given that reproductive physiology is highly sensitive to thermal stress, there is increasing concern about the effects of climate change on animal fertility. Even a slight reduction in fertility can have consequences for population growth and survival, so it is critical to better understand and predict the potential effects of climate change on reproductive traits. We synthesised 1894 effect sizes across 276 studies on 241 species to examine thermal effects on fertility in aquatic animals. Our meta-analysis revealed that external fertilisers tend to be more vulnerable to warming than internal fertilisers, especially in freshwater species. We also found that increased temperature is particularly detrimental for gametes and that under certain conditions, female fertility is more sensitive to warming than male fertility, challenging the prevailing view that males are more vulnerable. This work provides valuable new insights into the effects of temperature on fertility, with potential consequences for population viability.