Environmental factors limiting fertilisation and larval success in corals

Early life history stages of corals, including fertilisation and larval stages, are susceptible to changes in the chemical and physical properties of seawater, which can severely diminish pre-settlement success. Understanding these limiting factors is therefore important for understanding and predicting population establishment and persistence in novel or changing environments. A review of the literature identified numerous, often-overlapping properties of seawater that have the potential to impact fertilisation and larval survivorship, including salinity, temperature, pH, suspended sediment, nutrients, and heavy metals. Using published experimental data, this study aimed to quantify the influence of seawater properties on fertilisation and larval survivorship probabilities. I found that fertilisation success was most impacted by salinity, copper, phosphorous and sediment, and that larval survivorship was most affected by copper, lead and temperature. I evaluated success through both fertilisation and larval survivorship in order to identify the joint probability of survival in seawater with different chemical and physical properties. This combined model would be suitable for identifying locations that are environmentally compatible with coral larval survival and growth both presently and under future water quality scenarios. This model could therefore be used as a monitoring tool for assessing the potential for the early development of corals as well as recommending targets for water quality in coastal waterways.