Episode 3 | 17m 32s | Video has closed captioning.
The South Pacific island nation of Vanuatu may be one of the world’s most beautiful diving destinations. Its coral reefs are the backbone of the island’s environmental and economic health. Today they face destruction from a silent predator that can rapidly decimate an entire reef. Dive in with Alizé to discover how local communities are adapting to the threat and reviving coastal ecosystems.
Aired: 09/13/21
(horn blowing) (dramatic music) (cock roosting) - This used to be a football field.
- Yeah.
- [Alize] Wow, that just shows how much the sea levels are rising.
Right now, our environment is facing rapid and dramatic change.
From global warming to rising sea levels, to new invasive species.
As a global community, we know what we need to do to address these problems at their source, but we will also have to adapt.
In fact, for millions of people around the world, adaptation is already a part of everyday life.
My name is Alize Carrere.
I'm a scientist, a national geographic explorer, living in Miami, Florida, a city where adaptation to climate change is right at our doorstep.
I study how human lives are impacted by environmental change.
And in my work, I envisioned the kind of futures we want to live in.
My research has taken me around the world where I've learned from communities who have had to experiment with new ways to survive.
From the reefs of the South Pacific, to the rivers of the American Midwest.
In this series, we'll discover some of the innovative and surprising ways people are learning to adapt.
These are their stories.
(upbeat music) Welcome to Vanuatu.
This specific nation is made up of 83 islands, each wrapped in rugged coastlines and surrounded by incredible turquoise waters.
Vanuatu is part of Melanesia, which is one of three major cultural areas in the Pacific Ocean.
The people of Melanesia have thrived on these islands for centuries, relying on the bounty of the seas, right at their doorstep.
Here in Vanuatu, life moves freely between land, reef, ocean and back again, like the swiftly moving tides.
But today, Vanuatu's life-sustaining coral reefs, are under a series of threats.
Climate change is wreaking havoc on the region.
Warming waters are bleaching corals and causing massive die-offs, cyclones are stronger and more destructive.
And overfishing, particularly of colorful reef fish for the international aquarium trade, deprives the corals of their trustworthy gardeners.
Reef fish are crucial for keeping the underwater ecosystem in balance.
In Vanuatu, and elsewhere across coral reefs of the Pacific Ocean, another threat looms.
It has no brain, but it moves in highly coordinated ways.
And you can chop it up only to find several more in its place.
- This thing- - It's an outbreak.
- There's been massive devastation.
- I've been diving a lot and I've never seen this.
- One day, they can devastate an area that's 100 meters square.
- It's a disastrous animal.
They really damage our reefs.
(upbeat music) - [Alize] These are Acanthester planci, otherwise known as crown-of-thorns sea stars or COTS for short.
They're named for the long venomous spines that cover their body and their many arms.
They're among some of the biggest and fastest moving starfish in the world.
And unfortunately, they love to feast on coral.
Crown-of-thorns eat coral polyps.
Polyps are the living part of coral.
The small soft-bodied organisms that are protected by their hard limestone skeleton, the structure of the coral.
Crown-of-thorns do this by inverting their stomach through their mouth, sucking down the coral polyps.
During an outbreak, 1,000s of crown-of-thorns chow down across a reef, leaving behind dead coral.
Crown-of-thorn sea stars are native to the Indo-Pacific region, but their outbreaks have gotten more frequent and more damaging over the years.
Nutrient runoff from agriculture, overfishing, and stressed corals from cyclones and other effects of climate change are all reasons why crown-of-thorns are proliferating.
In Vanuatu, I got to meet a few incredible people who have spent years working to protect their reefs from these threats.
Meet Willie, Ronneth and Tatu.
In addition to being local marine conservationists, these guys are fathers, innovators and community leaders.
I talked to each of them about their experience dealing with crown-of-thorns.
One thing I forgot to mention, you do not want to come in contact with one of these starfish.
- If goes straight into your finger, you almost die for the pain.
- It's really painful.
- Let me ask you, have you ever been stung by crown-of-thorns?
- Yeah, I've been stung once.
I think somewhere here, see?
Yeah, many people in the community, they were stung by crown-of-thorns.
- You've only been stung once.
- Only once, yeah.
- Wow, you must be really good at being careful when you're there.
(man laughs) It's good.
No, because i don't know if it was like- - Like here, here.
- Here.
- As you can see, right here, and here.
- Wow.
- And today, there's another one here.
- Wow.
- [Alize] I wondered how the people of Vanuatu could possibly manage the problems that crown-of-thorns presented.
It turns out a lot of different ways.
The next day, we went out on the water with Peter Whitelaw.
Peter is originally from Australia, but he's been in Vanuatu for the last 40 years.
He runs a dive operation, aboard his trimaran and was able to shed some light on the many reasons why crown-of-thorns can be such a problem.
Like the fact that they're prolific breeders.
- One mother can put out 20 million eggs in one spawning, and she might have three spawnings in one year.
- [Alize] Oh, that's a lot.
- [Peter] So you can see how very easily it could get out of control.
- [Alize] Peter has been keeping a log book of the different outbreaks and removal efforts over the years.
This is 2012.
- [Peter] 2012, yeah, November.
So here are all the divers we ended up getting as volunteers coming out with us.
- Wow.
- [Peter] This day, we got 504 crown-of-thorns, 19 bags.
Here, we had 330 COTS, 624 COTS.
So every period of a year, we took out over 6,000 and that was sort of minimal compared with Nguna and Pele, I reckon they took out 80,000.
- 80,000?
- Yeah.
Hideaway Island took out about 30,000.
- I mean-- - Big Blue that you dived with they took out over 8,000.
You don't like to have to kill anything on the planet, right?
You sort of respect every species, but these are so destructive when they get into an out of balance situation.
- [Alize] This explosion in crown-of-thorn populations has to do with a few different factors.
Here's the thing, crown-of-thorns don't really have many predators, once they reach their full size.
Their populations are kept in check when reef fish, and even healthy corals feed on them when they're still tiny little larvae floating in the water.
So when overfishing reduces the fish populations and when corals die off because of warming, ocean temperatures and destructive cyclones, crown-of-thorns can reproduce more quickly.
This has led to more frequent and more severe outbreaks in recent years.
- If we work together, we can actually eliminate them slowly.
- [Alize] The guys showed me, the different techniques they're using to manage crown-of-thorn populations on the reefs.
Most of them require diving down to depths where they hide out in-between corals during the day.
First is the hook and bag method.
This is just physically collecting and removing the crown-of-thorns one by one off the reef.
It's a pretty time consuming and labor intensive process, but it's also proven to be one of the most effective.
This method requires hooking the sea star and prying it off the coral, before very carefully rolling it into a large grain bag.
On our short dive, we collected at least 20 starfish each.
Once the bag is full, they tie it off and leave it on the bottom of the reef for a few days to let the starfish decompose.
A few days later, they return to the reef to open the bags and release the decomposed crown-of-thorns.
This is a delicious and much less dangerous meal for reef fish.
Yum.
The second method is by way of injections.
- The new technique now is to use injection using ox bile, the gallbladder fluid from the oxen, or we're using citric acid or vinegar.
So those three injection fluids, are probably be the preferred way for a big aggregation of crown-of-thorns.
(bright upbeat music) - [Alize] The key to this method is, making sure you inject enough of the solution into the crown-of-thorns so that it floods their system.
If you don't inject enough, or if you only inject one area, it might not be effective.
This method is a bit less labor intensive, than the hook and bag process, but still time consuming.
And it requires specialized gear that not all communities have access to.
The third method is something they're experimenting with, rather than leaving the crown-of-thorns in bags on the bottom of the reef to decompose, the idea here is to try using them as compost on land.
Willie and Tatu have set up a system to test this out.
- Now, we're gonna get them out of the bag and then let them out on the sand.
Probably a week or two, so it can be dry.
- [Alize] Wow, yeah.
- I wanna show you a later stage in the composting process.
Yeah, so this one was dried about two weeks ago.
So now, it's ready to chop them into pieces and then take them to the nursery site to be used as compost.
- [Alize] After chopping up the dried starfish, either with a machete or a starfish grinder, Willie brings the organic material to a nearby plot of land where food crops are being grown.
This small protected area is what Tatu calls the food security garden.
Tatu has been working on integrating decomposed crown-of-thorns with soil to make an organic compost for tree saplings.
- We put a crown-of-thorns spread out here to remove again salt from the ocean.
And it takes another week, one week.
- [Alize] Tatu does this so that rain will help wash away the salt from the starfish.
Salty soils aren't good for growing crops.
Trying to desalt the starfish is actually pretty hard and partly why this compost idea has been less successful than it.
Okay, so you're putting the crown-of-thorns in with the soil- - [Tatu] The soil.
And then you mixed up the soil and the crown-of-thorns.
After mix them up.
We transplant, now we plant.
So we're gonna plant this nut tree.
- Okay.
- We mix.
So- - All right, so there it is.
- There you are.
- [Alize] When they're mature enough, Tatu brings them to the garden for their final transplant.
- So that's a nut tree composted with crowd-of-thorns sea stars.
- Yeah.
- [Alize] The compost method is still being tested and there's a good chance it won't be the best solution in the long run, but that's what adaptation is all about, a willingness to try even if there's no guarantee it will succeed.
But food gardens aren't the only type of gardens you'll find around here.
Willie and Ronneth have created incredible coral gardens to help restore and rebuild damaged reefs, around Nguna and Pele Islands where they live.
- If you see the people from Nguna and Pele, they just live along the coast.
Most communities are living on the coastline, so we depend entirely on protein on the reefs, rather than going looking for wildlife, yeah.
- And so the project that you're working on right now with your community, doing the coral gardening, that's an attempt to re-establish some of the coral reefs around here, right?
- Yeah, the main idea behind helping young people working with me to re-growing the coral is just to take back the health of the coral reef.
Because of all these destruction, we feel like we have to do something to help the coral reef to get back its status.
- I'm really passionate about coral gardening for the last five years.
And it's one of my favorite thing to do in terms of marine conservation.
I wanna show you what I've got.
- I can't wait to see it.
- [Alize] Willie is the first person in his community to introduce coral gardening.
He started in 2013 after learning about the process from friends and colleagues.
And he's now working to transfer his knowledge to other islands in the area.
His coral garden beds are beautiful.
They also provide an important habitat for reef fish.
The coral garden process doesn't happen overnight.
It took five years for Willie's coral bed to grow to this point.
If it weren't here, the area would be pretty devoid of any life at all.
Ronneth has also been working on coral gardening.
The approach he's been developing is by way of a rope nursery.
He makes coral cuttings and attaches them to ropes so they can regenerate.
- [Ronneth] Make sure you take about this size.
You know, about this length.
And then, make sure about, maybe 20 centimeter and you flip the rope open.
And you push this inside and then you twist back.
And that's it.
- Great.
- [Ronneth] Then you go to the other one.
- [Alize] When the corals on Ronneth's ropes reach a good size, he brings them to a degraded area of the reef, using nails, wire, a hammer and zip ties.
He tightly secures the ropes to the existing coral nuts.
The goal is to keep the coral fragments as close to the coral bedrock as possible, so they fuse together and regenerate over time.
This is definitely tricky because any little movement to the ropes will disrupt the coral's attachment process.
And the currents here were strong.
Willie is integrating this coral rope nursery approach to his garden too.
When we were checking out his site, they dropped down another frame that would be placed a few feet away from his original bed.
We connected the two beds with the ropes.
Willie cut off fragments from healthy corals, which we inserted a few inches apart on the ropes like Ronneth was doing.
These will take some time to grow before they can be transplanted to the reefs.
(upbeat music) In Vanuatu, there's no dividing line between life on land and life on the ocean.
The coral reefs connect the two, supporting productive habitats and rich biodiversity.
Willie, Ronneth and Tatu know this better than anyone.
Through their projects, they also teach the next generation the value of a healthy reef, whether for food, surfing tourism or protection from storms.
Ensuring the reef's protection means ensuring life itself, but as the ocean surrounding Vanuatu continues to warm, acidify and rise, adaptation will become an evermore urgent and complicated process.
Collecting sea stars won't be enough.
The future of many Pacific Island nations depends on how quickly the rest of the world will take collective action to address these issues at their source.
That might seem impossible, but what I encountered on this trip was an optimism that was contagious.
A fierce commitment to protect our home, can unleash a creativity and passion that has the power to rewrite the future we all inhabit.
The people of Vanuatu will teach you that.
(birds squeaking) (waves crushing) (upbeat music)
Adaptation.
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