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A First Post-Cyclone Look at Coral Reefs in the Vatu-I-Ra Seascape

By Sangeeta Mangubhai

[This is the second in a series of blogs by WCS-Fiji Director Sangeeta Mangubhai assessing the damage to coral reefs caused by Cyclone Winston, a Category 5 storm that hit Fiji on February 20]

Our first dives were in and around the Vatu-i-Ra Conservation Park, which has been proposed as a conservation area by local communities from Nakorotubu District. This initiative would be part of a unique partnership with local dive tourism operators and the Ra Provincial Office, supported by the Wildlife Conservation Society.

We knew the eye of Cyclone Winston passed over Ra, destroying up to 90 percent of people’s homes throughout the province while churning up the sea in its path. So we were expecting some damage to the reefs.

A longnose hawkfish settles on a fan coral that survived cyclone Winston. Photo by Sangeeta Mangubhai ©WCS.
A longnose hawkfish settles on a fan coral that survived cyclone Winston. Photo by Sangeeta Mangubhai ©WCS.

Heading out to our first dive site, we saw in the distance Vatu-i-Ra – an island of cultural and historical importance to the village of Nasau and home to nine species of breeding seabirds. With more than 20,000 pairs of breeding Black Noddies (Anous tenuirostris), the island is recognized as an Important Bird and Biodiversity Area.

What was apparent, even at a distance, was that almost all of the trees on Vatu-i-Ra Island seemed to be stripped of their leaves and very few seabirds could be seen. Without the leaves for cover, arboreal nests and chicks will not survive. We will know more next month when BirdLife International, NatureFiji-MareqetiViti, and the Wildlife Conservation Society partner up to do detailed assessments of the island and surrounding reefs.

Soft corals flourishing in the Vatu-i-Ra Seascape. Photo ©Janet McClelland.
Soft corals flourishing in the Vatu-i-Ra Seascape. Photo ©Janet McClelland.

As I rolled back off the skiff into the water for my first dive, I was dreading what was below the surface. But when I opened my eyes and descended down to 20 meters, I was surprised by the condition of the reef. While there were broken branching and plating corals and larger coral heads that had fallen over in the storm surge, the majority of the reef was mostly intact.

Hard corals, critical for building coral reefs and providing a home and shelter for small fish and invertebrates, were still abundant at all depths including in the shallows. In fact the cyclone seemed to have churned up the water and fish schools were thriving on an abundance of plankton (small microscopic animals) in the water column.

Sangeeta Mangubhai surveying reefs for cyclone damage and coral bleaching. Photo ©Jack Sue Drafahl.
Sangeeta Mangubhai surveying reefs for cyclone damage and coral bleaching. Photo ©Jack and Sue Drafahl.

What was missing, though, were the beautiful colorful soft corals and sea fans that Fiji is well-known for, and for which divers travel across the world to visit. Wind and wave action had uprooted this magnificent reef life, leaving behind bare scoured rock surfaces. Within two weeks of the cyclone, these areas were already covered in a fine layer of green turf algae.

However, as long as there are enough herbivorous fish in the water, over time this layer of turf algae will be consumed and the hard and soft corals that survive will spawn and produce larvae that will settle and recruit back onto the reefs. Disturbances such as cyclones can actually be good for reefs by opening up space for new species provided the damage is not catastrophic.

Soft corals flourishing in the Vatu-i-Ra Seascape. Photo ©Janet McClelland.
Soft corals flourishing in the Vatu-i-Ra Seascape. Photo ©Janet McClelland.

I am relieved to see that the damage to the Vatu-i-Ra Conservation Park and surrounding reefs is not catastrophic and to know that those reefs will continue to thrive and remain productive. If well protected, the conservation park may provide a refuge for coral and reef fish species and help reseed adjacent reefs.

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Dr. Sangeeta Mangubhai is Director of the Fiji Program for WCS (Wildlife Conservation Society). Follow Sangeeta on Twitter at: @smangubhai.

 

Other blogs in Sangeeta Mangubhai’s series exploring the damage to Fiji’s coral reefs following Cyclone Winston:

* After Winston: Assessing Coral Reefs for Cyclone Damage and Coral Bleaching

* Diving Nigali Passage in Gau

* Coral Bleaching in the Vatu-I-Ra Seascape: How Bad Is It?

Comments

  1. Sereana Cokanasiga
    Navua, Fiji
    March 10, 3:45 pm

    Consoling to know that the marine life and habitat has its own way of rehabilitation itself. Thank you Dr Mangubhai.

  2. Seitiale Tonuia
    Port-Vila
    March 10, 8:06 am

    Thank you Dr Manguhai for that informative article. It is usually predictable that natural hazards such as cyclones can have devastating effects on our surroundings. It is fortunate that not much damage was done to the Vatu-i-Ra Conservation Park as a result of TC Winston especially considering the fact that it was a category 5 TC.

    Cheers