Climate change will affect populations and communities of marine fishes in many ways, ranging from indirect effects associated with habitat degradation and altered resource availability to direct effects of rapidly changing environmental conditions. In the short-term (up to 2030), the impact of climate change on Australia’s tropical coastal and demersal fishes is largely tied to the fate of critical benthic habitats, especially for coral reef environments, which are highly vulnerable to elevated temperature and ocean acidification. There is good evidence and high consensus that climate-induced coral bleaching affects the community structure and abundance of reef-associated fishes, especially when it leads to the structural collapse of reef habitat. In the longer-term (after 2030), sea level rise and altered rainfall patterns will also significantly alter coastal wetlands that are important nursery areas for estuarine and nearshore species. In addition to the effects of habitat degradation, warmer ocean temperatures will cause distributional shifts in some tropical fishes, increasing the geographic ranges of some species and decreasing the ranges of others, including some commercially important species. Life history traits and population dynamics will be affected by warmer temperatures, with potential implications for fisheries yields. Altered oceanic circulation and ocean acidification could have very significant effects on populations and communities of coastal fishes. However, these impacts are still poorly understood and are likely to become most apparent in the longer term. There are a many critical knowledge gaps in our understanding of the effect of climate change on tropical marine fish, including the impact of warmer temperatures on adult reproduction, and the development, survival and behaviour of larvae; the effect of ocean acidification on the development, survival and behaviour; and the degree to which fish will acclimate or adapt to the expected rapid climate change. Non-reefal environments and commercially important species are especially understudied in relation to climate change impacts. Key strategies in mitigating effects of climate change on coastal marine fishes are to maintain and restore habitat quality, incorporate climate uncertainty into fisheries management plans, and limit impacts of other human activities in coastal regions
