About This Project

The response of Yellow Tang to the projected 4°C rise in Indo-pacific sea surface temperatures remains unknown. These fish play an important role in maintaining coral reef ecosystem health, just as they represent an economically important fish to the aquarium industry. The more we can learn about them now, such as thermal maxima and corresponding metabolic rates, the more prepared we will be to help mitigate the effects of warming ocean temperatures on this delicate species.

Ask the Scientists

What is the context of this research?

While many studies have examined the effects of rising sea temperatures on corals, far fewer focus on the predicted effects on reef-associated fish species. Herbivorous fishes, such as the Yellow Tang, exert system-wide influences on the reef by restraining the overgrowth of algae. Such an overgrowth can in turn suppress or even kill corals.

Reduced populations of herbivorous fishes because of overfishing and habitat degradation have already been known to cause a shift in reef ecology from coral to algae dominant. This type of ecological shift can preclude corals from recovering from disturbances like hurricanes, thus it is important to determine if rising ocean temperatures are likely to have significant negative impacts on herbivorous reef fish, and thus further the ecological shift.

What is the significance of this project?

Coral reef systems are hubs of biodiversity for fish, invertebrates and corals while their sensitivity makes them great bio-indicators. Coral reefs serve other functions, including acting a nursery ground, protecting coastlines from erosion, and supporting local economies through tourism and fishing. Herbivorous fish, such as Yellow Tang play a critical role in maintaining coral reef systems, thus a population decline could prove disastrous.

What are the goals of the project?

My project will quantify the metabolic responses of Yellow Tang to rising ocean temperatures on the reefs of Hoga Island, Indonesia. Yellow tang are of particular interest given their wide geographical distribution, from the Indo-Pacific to the Hawaiian Islands. While thermoregulatory behavior has been studied in Hawaiian populations, citing Yellow Tang's preference for cool water (21°C) consistent with that of other cool water species, no studies have looked warm water tolerance of the genetically distinct Indonesian populations.

To do this I will test the resting metabolic rates (RMR) and the critical thermal maximums (CTmax) of 120 wild caught tang. My trials will analyze the RMR and CTmax of fish held in the lab at current reef temperatures, and at the predicted ocean temperatures.