Fiji Travel Guide and Tips: Volunteering in Fiji Marine Conservation and Research!

The news sites are constantly talking about it: Sustainability!

As a tour company, we understand the urgency and importance of this topic, that is why we created an amazing tour to Fiji combined with sustainable activities for the coral reefs. Coral reefs are crucial for our marine life and our own survival, thus it is of high importance to maintain these gorgeous reefs.

One of the biggest threats for coral reefs is Climate Change. Already 75% of the Earth’s tropical reefs experienced bleaching between 2014-2017, and almost 30% of the reefs reached mortality level. Scientist conclude that bleaching happens 5 times more often than 40 years ago.

Not only does climate change have an impact on these reefs, but the Crown of Thorns Sea Star (COTS) can cause quite some damage.

This type of starfish causes serious harm if it is left to breed out of control. A fully-grown COTS can destroy 10 square meters of coral each year, and it can lay 50 million eggs in a single breeding season.

On our Fiji tour,  you and a professional Marine Biologist will identify and count the COTS in one area to be removed. This is a truly unique experience to explore the beauty of Fiji and help out an important ecosystem.

What is the Crown of Thorns starfish (COTS)?

Crown of Thorns starfish (COTS) is a spiky and spineless marine creature that normally occur in the Indo-Pacific region. They feed on coral, and if not controlled they can have devastating effects on the hard coral communities. When COTS occur in normal numbers and on healthy coral, they play an important role in the ecosystem. They tend to eat the fast-growing coral, and this gives the slower-growing species also a chance to develop and catch up. This boost diversity in the reefs. However, COTS can reach plague numbers. With the right conditions, they can lay 50 million eggs in a single breeding season. The survival chance of this larvae increases dramatically when early-season monsoonal and cyclones occur, also overfishing stimulates outbreaks.

What is the problem with Crown of Thorns starfish?

The Crown of Thorns starfish are feeding themselves on large swaths of coral reef. In the past, people were afraid these starfish would cause permanent damage to the reefs. So they combined forces to control the population size. However, this worked backward because COTS has the ability to regenerate arms and even regenerate from half an animal in extreme cases. These starfish reproduce itself through behavior which is also known as broadcast spawning. The males are releasing sperm at the same time the female releases her eggs into the water column above the reef. This increases the likelihood that the eggs will become fertilized. Not only do they cause damage and increase their fertility rate, but COTS can also threaten other species when their locally high numbers of these starfish.

How does the Crown of Thornes starfish adapt to its environment?

The most important feature for the starfish to adapt itself to the dangerous marine environment is the fact that they can regrow almost their entire body. This adaption is possible because their vital organs and nerve systems are located in their arms. Starfish don’t have a brain that can be injured. The bodies of the COTS are though and bony, this enables them to protect them against their predicator. The bright colors on the starfish help him to scare or confuse attackers and they are covered with venomous spikes to protect their bodies from enemies. They are able to move in their surroundings by their seawater vascular system that powers their tube feet by circulating nutrition. And they are able to produce a huge amount of eggs, which helps them with a better chance of survival.

Do Crown of Thornes starfish cause coral bleaching?

No, the Crown of Thornes starfish does not cause coral bleaching. During an outbreak COTS is able to strip up to 90% of the living tissues of the reef, this does cause a lot of damage to the reef but no bleaching. COTS feeds on coral polyps which is the structure of the coral reefs, but these organisms are translucent. Zooxanthellae are the ones responsible for the color of the reefs. Bleaching is being caused if these zooxanthellae are expanding due to stressing conditions for the coral. Some examples of stressing conditions are an increase and a decrease in water temperature.

What does the Crown of Thorns starfish do to the coral reef?

The COTS pray on all sorts of different corals. They eat the coral pray by wrapping themselves around the coral while extruding their stomachs out of their bodies. This enables them to release enzymes to digest the coral polyps. These are tiny soft-bodied organisms who form the structure of the coral reefs. When a polyp attaches itself to a rock on the ocean floor it divides or buds itself into thousands of colonies, and reefs start to appear. These colonies grow over hundreds and thousands of years and connect with other colonies to create big reefs, thus they act as a single organism. The removal of these organisms does damage the coral, but they are able to recover and grow back.

Are Crown of Thorns starfish poisonous to humans?

Yes, COTS are poisonous to both marine life and humans. They can have between 7-23 arms and can reach a length of a meter. These venomous spikes can be found all over their bodies and can grow up to 5 centimeters long. Their spikes contain toxins and they are quite sharp as they manage to pierce through a wetsuit. The toxics leaves a puncture wound that is laced with venom, this can cause vomiting, nausea and severe pain.

How do you remove COTS?

In order to control the outbreaks and the damages the COTS are causing to the reefs, several ways have been tested to find the best removal procedure.

- physical Removal:

Out of the 3 removal procedures, physical removal is the one recommended. Experienced divers can use several different rods to remove the starfish of the rock, think of a PVC pipeline, metal spear, wooden stick or a boat hook. The starfish who have been removed can be placed in a large canvas bag and brought on shore. However, the spikes of the starfish can penetrate through the bag, so do this carefully. May there be shallow water, they can also be removed by snorkeling. Once the starfish are on land they can be disposed  by the means of burial or burning. The advantage of this method is the low cost and that the COTS can be used as compost or fertilizer. The disadvantages are that it requires a lot of physical effort, and this can be potentially dangerous.

-        Chemical Injection

Another removal procedure is chemical Injection. The most common and environmental safe poison to use at the moment is oxgall, bile salts No.3, and vinegar. The poison is injected with a needle at the base of the starfish arms. This method is more effective than Physical Removal but some chemicals can be toxic for the environment and its animals. This process has a much higher cost and getting the necessary equipment for it might be difficult. Next to that, if the injection is given at the wrong place the starfish will regenerate its arms or even spawn and this is not ideal.


-        Mutilation

The last removal process is Mutilation. This is the direct killing of the starfish by ripping them into pieces. But this method is not recommended as the starfish can regenerate itself, added that the starfish can spawn when it feels stress or agitated. You can put the starfish into a mesh bag and leave them underwater. At high densities, the starfish will use up all the oxygen and they will die in 2-3 days.  

What will you do on your Fiji tour?

On this Fiji tour, you will start with a talk from the marine biologist on the impact climate change is having on the Fijian underwater environment. After that, you will enter the water, and assist him during the snorkel trip to help with the COTS Survey. This exists out of identifying and counting the amounts of COTS which can be removed from the coral reef. All proceeds which are contributed by you in your Real Fijian Adventures tour price for this activity will directly go to further conservation projects on the reefs of Fiji.

This tour in Fiji is specially designed to help out the environment with an environment-friendly activity to keep this natural paradise clean and healthy for the next generations to come. Are you excited to explore Fiji and do something back for our important marine life? Then this is the perfect tour for you.





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