A Bleached Coral Reef that Recovered

Can Coral Reefs Recover?

In our last post, we shared a conversation we had with Madhu (MD Madhusudan), one of the founders of NCF (Nature Conservation Foundation).

We talked about how conservation should be rooted in science.  And how the best solutions include partnership with local people to be successful.

Our last post was about tigers and other large animals.  But Madhu also shared with us a story about a coral reef off India’s coast, and how it survived a worldwide bleaching event when many other reefs didn’t.  The story begins with El Niño.

El Niño and Coral Bleaching

El Niño is a warming of the water temperatures off the Pacific coast of South America, about every 2 to 7 years.  It’s a natural event, and has occurred regularly for at least the past 300 years, and probably for a lot longer.  Recently, El Niño events have been more frequent, likely due to global warming.

Coral needs a certain water temperature to live.  If temperatures get too high, the coral begins to die and turn white.  This is called bleaching.  There was a worldwide coral bleaching event in 1998, as a result of rising sea temperatures caused by El Niño.

Many reefs didn’t recover, but the Lakshadweep reef off India’s coast did.  Why?

Location of the Lakshadweep Islands. Image from Wikimedia Commons.

Location of the Lakshadweep Islands.
Image from Wikimedia Commons.

NCF studied the issue and discovered the answer:  after the bleaching event, algae started to grow on the Lakshadweep reef.  Too much algae can destroy a reef, and in many areas around the world, algae outcompeted the coral.  But in India, it didn’t.  There were two key factors that made a difference:  people, and fish.

Understanding the Human Impact

The government had given residents of a nearby island boats and training, so they could fish for pelagic tuna in a dolphin-friendly way.  Pelagic fish live in open oceans, not near the shore.  So, with their new boats and training, the people of this island started fishing further out at sea.

As a result, the Lakshadweep reef was largely free of fishing pressure at the time of the worldwide bleaching event in 1998.  And when algae started to develop on the bleached reef, large numbers of herbivorous (plant-eating) fish, like surgeon fish and parrot fish, were there to eat the algae.  So the reef started to recover.

In many other areas of the world, where people fish more intensively around reefs, the coral has a harder time recovering, because there aren’t as many algae-eating fish.

Staying With the Problem

But this isn’t the end of the story.  NCF has continued to monitor the reef.  Taking a long-term approach — studying an issue over long periods of time — helps NCF see what changes may be happening, and identify new problems and pressures.

By continuing to monitor the Lakshadweep reef, NCF has seen a new problem:  now, the reef is under intense pressure from fishing.  This increased fishing pressure may leave the reef less resilient in the event of future coral bleaching.

Why is there more fishing now?  What’s changed in the 16 years since the reef was affected by coral bleaching?  One change is that now, fishing operations have access to cold storage — caught fish can be kept cold and fresh, making it easier to catch larger numbers of fish.  And fish prices have changed, making certain fish now very profitable.

NCF is looking at solutions; one unexpected solution may be… recipes.  There are local recipes that completely depend on particular species of fish at the reef.  If these species disappear, a part of the local culture will be lost, so NCF is getting older people to talk with younger people about their importance.  This is a great example of how conservation programs can be created thoughtfully, in harmony with local people.

If the reef isn’t protected, it may impact local people dramatically.  Coral reefs sometimes protect islands.  If a reef is destroyed, nearby islands may be as well.  So, the stakes could be very high for local people if reef areas are overfished.

Why We Shared This Story

Despite the current concerns about the reef, we wanted to share this story because it carries a hopeful message:  that natural systems, like coral reefs, can be resilient, given the right circumstances.

We also thought this story illustrated how good conservation combines scientific research with an understanding of how humans impact the environment.

And, it shows how conservation is a long-term issue:  conditions change, and new solutions may be needed.  By continuing to support conservation efforts over the long haul, we give them the best chance of success.

 

Study Guide Questions

1. What is El Niño?

2. What has been the likely impact of global warming on El Niño?

3. What is coral bleaching?

4. What did local fishermen do that helped Lakshadweep reef recover from the bleaching that occurred?

And, if you want to see more about coral bleaching, check out the video post we did about the Ningaloo Reef in Western Australia a few months ago.

If you are an educator, we’ve created a page to help you leverage content we’ve created, including an index of our posts.

 

 

 

 

 

 

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