Tropical cyclones are one of the most destructive natural disturbances to coral reef ecosystems. Severe cyclones can have serious implications for the food availability, security and income of coastal communities in tropical regions.
A study titled “Responses of benthic habitat and fish to severe tropical cyclone Winston in Fiji” has revealed that despite the large amount of damage caused to corals, minimal impacts were observed on fish communities. The study by researchers from Curtin University, Australian Institute of Marine Science and the Wildlife Conservation Society (WCS) appears in the latest edition of the journal Coral Reefs.
Cyclones commonly occur throughout the tropical regions and have historically been a natural regulator for coral diversity on reef ecosystems. However, with climate change more cyclones are expected to reach the highest categories, which has the potential to cause greater damage to coral reef ecosystems, impacting coastal communities which rely on reef resources for food and livelihoods.
Cyclone Winston passed through Fiji on the 20 February 2016 and at the time was one of the most severe and devasting cyclones to occur in the Southern Hemisphere. To find out the extent of damage caused by cyclone Winston coral reef surveys were done on reefs in Kubulau and Levuka districts in Fiji. Researchers used specialised underwater camera systems (https://www.youtube.com/watch?v=aCGb_kfeGqI&ab_channel=MethodsEcolEvol) to count, measure and identify fish and coral communities after cyclone Winston and compare it to fish and coral data collected pre-cyclone.
Lead author Brae Price explains “The results showed that damage to coral communities was much worse in Levuka compared to Kubulau, due to cyclone generated waves being larger and lasting longer in Levuka. Waves in Levuka reached a massive 14.37 m and were greater than 9 m high for ~8 hours compared to 9.39 m which lasted for ~1 hour in Kubulau.”
He further added “Despite the severe damage to live coral, fish communities were not impacted heavily. Only corallivorous fish which rely on live coral for food showed some declines, and this was limited to survey sites where the most coral damage occurred. However, a number of the reefs we surveyed were relatively healthy, which may have buffered from the effects of the cyclones compared to other locations”.
Cyclones are unpredictable and devastating natural disturbances which makes it hard to predict where or how much damage a cyclone will cause. Through research on cyclones of different categories occurring in different areas, scientists are starting to unravel the true impacts that these disturbances are having on coral reef ecosystems.
WCS Fiji Country Director Dr Sangeeta Mangubhai added “we have managed to return to Kubulau in 2020 and are delighted to report that coral communities have bounced back in community tabu areas, like the Namena Marine Reserve, and were spared damage from the more recent 2020 Cyclone Yasa. The work by Brae is critical for us to understand the impacts to coral reef systems – it is important more than ever that we look after our coral reefs so that can resist or bounce back quickly from cyclones and other disturbances.”
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The authors of the study are: Brae Price, Euan Harvey and Benjamin Saunders of Curtin University, Sangeeta Mangubhai of the Wildlife Conservation Society, Maji Puotinen of the Australian Institute of Marine Science, and Jordan Goetze of the Department of Biodiversity, Conservation and Attractions. This research was supported by the Wildlife Conservation Society and Curtin University, and funded by a National Geographic Society early career grant (Grant No. EC-183C-18) to the lead author.