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Coral bleaching in Seychelles: What you need to know

By Petrina Darrah 1 month ago

A coral reef bleaching event was recently confirmed in Seychelles. How are GVI’s research centre and volunteer programs in Mahe helping to monitor the region’s corals?

In the last 30 years, around half of the world’s corals have died due to factors such as ocean warming and acidification. According to the Reef Resilience Network, 75 percent of the world’s coral reefs are currently threatened.

Seychelles’s reefs have recently been struck by another coral bleaching incident, further jeopardising the delicate marine ecosystems in the region.

What is coral bleaching and how does it happen?

coral bleaching

Original photo:  “Coral bleaching at Lizard Island March 2016” by The Ocean Agency/XL Catlin Seaview Survey/Richard Vevers is licensed under CC BY 2.0

Corals are delicate organisms sensitive to and easily affected by temperature, overfishing, pollution and sedimentation that clouds the water, and blocks off much-needed light.

When stressed by changes in their environment, corals expel the symbiotic algae that live in the inner layer of its skin. This causes them to turn white, giving them a bleached appearance.

Healthy corals depend on these microscopic algae to survive. The algae feed the coral; in return, coral polyps provide the algae with shelter. Without algae, corals lose their major food source and eventually starve.

Coral can recover from bleaching, but if the environmental stress continues and reefs are left without algae for an extended period of time, they will eventually die.

Warming seas are the primary cause of coral bleaching. An increase of carbon dioxide in the atmosphere, due to pollution, has led to a spike in sea temperatures, particularly along the ocean surface. These are becoming more severe and lasting longer.

As corals already exist in tropical conditions near the limit of their thermal tolerance, slight changes in sea temperature can have a great impact. A rise in temperature of just 1°C or 2°C is enough to turn coral white.

 

coral reef bleaching

Why is it important to conserve coral reefs?

Coral reefs are the most diverse marine ecosystems on the planet. They might cover only one percent of the ocean floor, but 25 percent of all fish species will spend at least part of their life cycle in one, according to the World Economic Forum.

When coral dies as a result of climate change, fish communities in the area also decline. Scientists found that after a mass bleaching event in 1998, deteriorating reefs in Seychelles resulted in a loss of species and reduced fish populations.

As well as providing a habitat for thousands of animal species, people around the globe depend on fish from reefs, the tourism they generate, and the coastal protection they offer. More than 100 million people depend on coral reefs for survival, Reef Resilience says.

 

coral reef conservation

Major coral bleaching events in Seychelles

Between March and May 2019, a coral bleaching event occurred in Seychelles. Surface sea temperatures crept up to 31°C and caused widespread damage to reefs in the area.

This event was caused by tropical Cyclone Idai, which delayed rains from moving northward, and prolonged hot, summer conditions in Seychelles. This meant greater stress for corals.

This is the third significant coral bleaching event to take place in Seychelles’s coral reefs.

Seychelles lost up to 90 percent of its coral reefs in 1998, during the biggest El Niño weather event ever recorded in the western Indian Ocean.

 

coral bleaching statistics

 

For a relatively short period of a few months, seawater temperatures rose by 2° to 3°C. This slight increase caused a major coral bleaching event. One of the bleakest coral bleaching statistics is that every coral reef in the world was affected by bleaching in 1998.

Another bleaching event occurred in 2016 and hit the partially-recovered reefs. It caused a devastating 50 percent decrease in live hard coral cover, according to the Seychelles National Parks Authority (SNPA).

Experts predict that unless climate change is curbed, there will be annual bleaching events around Seychelles by 2050.

How can we conserve coral reefs?

coral bleaching facts

 

As part of our commitment to the United Nations Sustainable Development Goal (UN SDG) of protecting life under water, GVI works alongside the SNPA to help monitor Seychelles’s coral reefs. Our activities include monitoring and collecting data on coral reefs, to help guide conservation strategies and understand more about these unique ocean ecosystems.

We also operate volunteer programs that allow international volunteers to contribute their time and skills to help carry out research and other critical tasks.

Volunteering with GVI is a direct way to contribute to coral reef research in Seychelles. Our volunteering programs and internships in Seychelles are also an opportunity to boost your marine conservation or professional diving career.

For example, while gaining your PADI Divemaster qualification, you could develop the techniques needed to survey coral reefs and learn how to identify different fish and coral species.

 

seychelles coral reefs

 

You can also take part in collecting data that our key partners, including the SNPA, can use to inform decisions around conservation in the region.

You could also help to study coral bleaching and contribute to our understanding of how to limit the damage from these events and encourage recovery.

Your role in coral reef conservation won’t end once you have completed your volunteering program and waved goodbye to Seychelles. You’ll be taking valuable knowledge home with you.

Choose to be an ambassador for healthy reefs, and inform your community about coral bleaching facts and other threats to these precious marine ecosystems. Encourage the people around you to join efforts to curb climate change, and help to ensure a future for healthy coral reefs.

Explore GVI’s volunteer programs in Mahe to find out more about how you can contribute to coral and marine conservation.