Equatorial Waters too hot for Reef Fish Species

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Reef Fish on South Caicos. Photo by Charlie Gaines.

Due to climate change, reef fish species that live near the equator have a threatened future because of increased sea temperatures. 

Jodie Rummer and her colleagues from the ARC Centre of Excellence for Coral Reef Studies at James Cook University in Australia, found that reef fish are extremely sensitive to temperature change, even relatively small temperature changes (2-3 °C).  The group of scientists observed the thermal range at which reef fish could optimally perform aerobic metabolic processes.  The study involved four species of damselfish and two species of cardinal fishes that were held for 14 days at 29, 31, 33, and 34 °C.  All six species of fish appeared to be living above or close to their thermal optima or thermal range for optimum aerobic performance.

Fish that live near the equator are particularly sensitive to global warming because they live in a stable thermal environment and have low toleration for thermal changes.  Coral reef ecosystems are currently facing biodiversity population crisis that is due to climate change.  The rising ocean temperatures may not be immediately lethal, but as the temperatures rise, the geographical distribution of these reef fish will change.  This means that the reef fish would have to adapt to a new area and ultimately cause problems for all the islands that flourish off these fish for a source of income and food.

With climate change affecting biodiversity rapidly, it is crucial to understand the relationship between organisms and their environments in order to implement affective management strategies for the conservation of future reef fish populations.

Check out the full journal here.

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Journal Reference:

  1. Jodie L. Rummer, Christine S. Couturier, Jonathan A. W. Stecyk, Naomi M. Gardiner, Jeff P. Kinch, Göran E. Nilsson, Philip L. Munday. Life on the edge: thermal optima for aerobic scope of equatorial reef fishes are close to current day temperatures. Global Change Biology, 2013; DOI: 10.1111/gcb.12455

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