A new study led by the University of Helsinki predicts how fish diversity will respond to declines in coral diversity and shows that future coral loss might cause a more than 40% reduction in reef fish diversity globally.
Corals increasingly bleach and often die when the water warms. What happens to fish if there are no alternative reefs to swim to? The few fish species that feed on corals will inevitably starve, but the rest might find alternative rocky habitat to persist. As yet, it has been hard to do the larger-scale studies that can project what fish will remain in a world without corals. A new study led by Giovanni Strona at the University of Helsinki finds that global projections of fish diversity without corals are as low as small-scale experiments suggest.
An international team of marine biologist started by mapping tropical fish and coral diversity across the world’s oceans for every square degree latitude and longitude. These unprecedented maps showed what marine biologists have long known, fish and coral diversity vary widely, with many more species in the Indo-Pacific “coral triangle” than in the western Atlantic and eastern Pacific. Marine diversity hotspots have been long explained by the way that latitude, habitat, temperature, and geography affect speciation and extinction rates among corals and fishes alike. After controlling for factors that drive diversity in general, the authors found that areas with diverse corals still tended to have more diverse fishes, suggesting that coral diversity begets fish diversity.
