High-latitude, deep water coral bleaching at Rottnest Island, Western Australia

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Thomson, Damian ORCID ID icon; Bearham, Douglas ORCID ID icon; Graham, Fiona; Eagle, Janelle


Journal Article

Coral Reefs




Coral bleaching is well documented on shallow, tropical reefs, however, there are no published records of coral bleaching on high latitude (26 °), deep (20m) reefs. High latitude, deep water reefs are less affected by thermal stress and may therefore act as a potential refuge site from global warming (Bongaerts et al., 2010). Here, we observed extensive coral bleaching in May 2011 at two high-latitude (32° S) deep-water (24 - 28m) reefs located on the western side of Rottnest Island, off Perth, Western Australia. Most colonies of Coscinarea marshae (n ≈ 100), a species endemic to southern Australia, were completely bleached, while all other coral genera were unbleached. Water temperatures between December 2010 and May 2011 at these sites were higher than average and NOAA SST records reveal 16-degree heating weeks (DHW) for the region. In-situ measurements confirmed temperatures were up to 4°C higher than the long-term monthly average for the 150 days prior to surveys (27th Dec 2010 to 25th May 2011) and these above average temperatures extended to a depth of greater than 50m. Our observations confirm that corals located on deeper, high latitude reefs are susceptible to thermal bleaching. Interestingly, at this location C. marshae is close to the northern limit of its range (Veron and Marsh, 1988), which may explain why it is more susceptible to thermal stress than the other species at Rottnest, which all have populations extending further north (Veron and Marsh, 1988). High latitude endemics may therefore be more susceptible to global warming at these sites and deserving of a higher conservation status within this region.


Coral bleaching

Marine and Estuarine Ecology (incl. Marine Ichthyology)


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© 2011 Springer


Journal article - Refereed


Thomson, Damian; Bearham, Douglas; Graham, Fiona; Eagle, Janelle. High-latitude, deep water coral bleaching at Rottnest Island, Western Australia. Coral Reefs. 2011; 30(4):1107. https://doi.org/10.1007/s00338-011-0811-x

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