The Heat Is On: Sea Turtles Are Becoming Mostly Female Due To The Earth’s Warming Climate

Some of the more charismatic inhabitants of the reef here at Gili Lankanfushi are the Turtles, and we do our best to help them thrive.

In fact, our resident Hawksbill Turtle, the aptly named ‘Gili’, was initially found here in critical condition, but was rescued by our marine biology team who sent her straight to the Four Seasons Rehabilitation Centre for recovery. Of all the threats posed to these animals; poaching, entanglement in fishing gear, plastic and other marine debris, and ocean pollution – There is one issue you may not be aware of: Climate change is turning Sea Turtles female.

As reported by Sarah Kaplan for The Washington post, scientists in the 1980s accidently discovered that temperature can determine the sex of Turtles. The team were attempting to aid a population of sea Turtles by rescuing eggs from vulnerable beaches and keeping them warm in incubators until they were ready to hatch. To their surprise almost all the hatchlings were male. What these scientists observed was “Temperature-dependent sex determination (TSD)”, a phenomenon that occurs only in reptiles (and some fish).

At what biologists call the ‘pivot temperature’ (roughly 29oC for Green Turtles), nests will produce equal amounts of males and females. A little warmer and embryos develop as females, but keep the eggs just a few degrees cooler (like the scientists did with their incubators) and they’ll come out mostly male.

Turtles tend to target their breeding periods to times when the sand is slightly warmer than their pivot temperatures, resulting in populations moderately skewed towards female, but a recent study conducted around Australia’s Great Barrier Reef found that the populations are becoming more than moderately skewed. On the warmer nesting sites 99.1% of juvenile Green Turtles were female, as were 86.8% of adults, suggesting that there has been a shift in gender ratios over the last few decades.

Scientific evidence for warming of the climate system is unequivocal
-Intergovernmental Panel on Climate Change

Global warming is rapidly emerging as a universal threat to ecological integrity and function, say scientists studying coral reef assemblages. In species with temperature-dependent sex determination the impacts of rising temperature are particularly pertinent. At the key breeding grounds of many Sea Turtle populations the sand has warmed significantly since the 1990’s and researchers say that this almost certainly accounts for the dramatic decrease in the number of males. Since turtles will often return to the same beaches where they were born to lay their own eggs, this cycle will likely continue; and with global temperatures continuing to rise, many Sea Turtle populations are in danger of high egg mortality and female-only offspring production.

“Finding that there are next to no males among young Northern Green Turtles should ring alarm bells, but all is not lost for this important population.”
– WWF Australia CEO Dermot O’Gorman

The good news is that management strategies are possible. Options include shading beaches or using artificial rain to cool the beach. Protecting some of the big breeding males from threats such as poaching and entanglement is also going to be of particular importance.

Of the seven species of sea Turtles in the world, five species have been recorded in the Maldives and some species are known to nest here: The Green Turtle (Chelonia mydas), Hawksbill Turtle (Eretmochelys imbricata), Olive Ridley Turtle (Lepidochelys olivacea), Loggerhead Turtle (Caretta caretta) and Leatherback Turtle (Dermachelys coriacea). The Maldivian archipelago clearly serves as an important habitat for Sea Turtles, and here at Gili Lankanfushi we strive to help maintain that habitat by educating our guests about the negative effects of global warming; reducing the amount of harmful marine debris entering the ocean and growing our seagrass beds that act as a carbon sink and produce food for our sea turtle population.

So, what can you do to help mitigate climate change? Start by finding ways to reduce your carbon footprint; embrace a minimalist lifestyle, walk instead of drive, [a comprehensive list of ways to reduce your carbon footprint can be found here and here] and support only the large companies that are reducing theirs too.

Acknowledgements:

Guarino, Ben. 2018. Climate change is turning 99 percent of these baby sea turtles female’. Washington Post.

Hogge, Katie. 2018. Not Cool: Climate Change Turning 99% of These Sea Turtles Female. Ocean Conservancy.

Jensen, M.P., Allen, C.D., Eguchi, T., Bell, I.P., LaCasella, E.L., Hilton, W.A., Hof, C.A. and Dutton, P.H., 2018. Environmental warming and feminization of one of the largest sea turtle populations in the world. Current Biology, 28(1), pp.154-159.

Kaplan, Sarah. 2016. Some like it hot: Scientists figure out why female turtles are born at higher temperatures. Washington Post.

WWF. 2018. How climate change is turning Green Turtle populations female in the Northern Great Barrier Reef. WorldWildLife.org.

PADI guest blogger Jon Fry introduces himself:

After receiving my degree in Marine Biology & Coastal Ecology from Plymouth University I worked in Madagascar where I gained experience in reef restoration and tropical biology. I believe awareness is the most important tool we have in conservation, and I am pleased to be here at Gili Lankanfushi where I can educate the curious about marine life and sustainability.

Green Sea Turtle Nesting on Earth Day 2018

In the early hours of Earth Day, 22nd April 2018, a female green sea turtle was coming to an end of her journey as she finished laying the last of her 150 ping pong ball sized eggs in the sand close to the tree line at Gili Lankanfushi.

The adult turtle was around one meter in size with her carapace (shell) measuring around 80cm. After arriving on the beach just before high tide (at 4:30am) she searched for a safe spot to lay her eggs in an area where the sand was soft enough to dig a hole around 50 cm deep.

She succeeded on her second attempt and went into a trance to deliver her clutch. We did not want to disturb her but used this opportunity to assess her size and check the hole was deep enough for her eggs.

After a two-hour process, she began to make her way back to the ocean. Her energy levels were high and her timing impeccable as she re-entered the water at 6:15am, just before first light.

The nest is in an area that could be disturbed by hosts or guests walking, so we constructed a make shift boundary to protect the eggs from the pressure of human feet above.

After a 60 day incubation period we hope to witness the emergence of the hatchlings as they make their way down to the ocean. Turtle hatchlings follow the light of the moon to reach the ocean so we will be sure to turn off external lights during this time as any light pollution could cause the hatchlings to make a wrong turn and reduce their chance of survival.

Female green sea turtles nest three to five times per season and they lay their eggs on beaches within a 100kilometre radius of where they hatched. We hope she is planning to nest again on Gili’s shores in the next few months. We noticed a unique marking on her carapace and we will try to use this white mark to identify her in the future. However, we were not able to get clear photographic identification as we did not want to disturb her behaviour by shining a light on her.

As she entered the water, we became acutely aware of the responsibility we had been given – to keep these eggs safe from disturbance and predators for around two months until they emerge as hatchlings.

As only one in 1000 turtle hatchlings make it to adulthood we can safely say that Gili is carrying precious cargo into the months ahead.

PADI’s guest blogger Clare Baranowski introduces herself:

I am a marine zoologist from the UK who has worked throughout the tropics researching mega fauna and reef ecosystems in the Caribbean and Indian Ocean. I have experience monitoring and restoring coral and surveying manta, turtle and dolphin populations. I began my career as a science communicator before moving into research and management roles, this is why I incorporate outreach and education into every project I work on and I hope to continue this at Gili Lankanfushi

Earth Day – Sunday 22nd April

On Sunday 22nd April, the Prodivers team and guests of Hurawalhi joined the largest civic-focused day of action in the world – Earth Day! The campaign for Earth Day 2018 was ‘End Plastic Pollution’, a movement dedicated to providing information and inspiration needed to fundamentally change human attitude and behaviour towards plastics.


Plastics are a substance the earth cannot digest. The very qualities that made plastics such an attractive material initially; durable, flexible, versatile and inexpensive, have ultimately generated rubbish with staying power – a huge environmental issue. Our voracious appetite for plastic goods, coupled with our tendency to discard, litter and thus pollute, has led to an estimated 8 million tonnes of plastic entering our oceans every year. Plastics not only threaten our wildlife through entanglement, ingestion and habitat disruption, but their ability to absorb chemicals and accumulate in the human food chain has also led to plastics negatively affecting human health.


So, instead of diving with sharks or snorkelling with manta rays, the 48th Earth Day saw Hurawalhi staff and guests dive and snorkel for debris instead! They were let loose to clean up as much plastic and rubbish they could find off a nearby reef. Whilst they may have made only the tiniest dent in removing some of the debris currently be in our oceans, every action counts. There are so many simple ways to reduce plastic consumption in our day-to-day lives, here are some of the tips our Marine Biologist, Kirsty, shared with all of our volunteers this Earth Day:

1. Refrain from using plastic straws, even in restaurants. If a straw is a must, purchase a reusable one.

2. Forget the plastic bag. Purchase a reusable produce bag and be sure to wash them often.

3. Give up gum. Chewing gum is made of a synthetic rubber, i.e. plastic.

4. Ditch bottles for boxes. Often, products like laundry detergent come in cardboard which is more easily recycled than plastic.

5. Leave the single-use plastic bottles on the shelf. Use a reusable bottle or mug for your beverages, even when ordering from a to-go shop.

6. Don’t buy foods in plastic containers e.g. berries, tomatoes etc. Ask your local grocer to take your plastic containers back.

7. Disregard the disposable nappy. Use cloth nappies to reduce your baby’s carbon footprint and save money.

8. Stop purchasing single serving products. Buy bulk items instead and pack your lunch in reusable containers and bags.

9. Refuse to buy disposable razors and toothbrushes. Purchase replaceable blades instead.

Abstain from buying frozen foods. Even though those that appear to be packaged in cardboard are coated in a thin layer of plastic, plus you’ll be eating fewer processed foods.

A great quote from Marine Biologist, Sylvia Earle, sums up perfectly the importance of looking after the ocean: ‘No water, no life. No blue, no green’

PADI’s guest blogger Kirsty introduces herself:

Growing up in Mallorca, surrounded by the riches of the Mediterranean Sea, Kirsty’s ambition to pursue a career in marine biology was ignited from a young age. Kirsty completed both her undergraduate and postgraduate degrees at Newcastle University in England. During her studies she had the opportunity to conduct fieldwork in the Bahamas, Bermuda and the Maldives. It is not surprising then that her research interests to date have focused on tropical reef ecology. More specifically, Kirsty is interested in studying the movement patterns and habitat use of sharks and rays. Kirsty is currently part of the Maldivian Manta Trust research team, collecting data around the country’s manta population, its movements, and how the environment and tourism / human interactions affect them.

 

 

Dive site topography in Lhaviyani Atoll – Part 1

The underwater topography of the Maldives is dramatic, varied and perfect for exploring. Scuba divers visiting the Lhaviyani Atoll in particular have a huge variety of reef formations awaiting them on the dive sites – the first glimpses of which can even be spotted from the seaplane window. In this, the first of a three part series, the underwater islands of giris and thilas are explored.

What is a giri?

Giris are shallow underwater islands with a top reefs lying at around 5 meters and appearing as blueish-green spots when viewed from the seaplane window. Typically found inside the atoll, they are perfect for beginner divers and macro lovers.

One of Hurawalhi’s favourite giris is Maa Giri. It means Flower Island and it is usually described as ‘fish soup’. On the front of the giri are thousands of lunar fusiliers catching food in the gentle currents that flow around the dive site. Once the divers descend a little deeper they can explore small overhangs and crevices where nurse sharks are sleeping or moray eels are getting cleaned. All around the giri are schools of yellow snappers, humpback snappers, and sweetlips. Occasionally, at the right time of the year, there is a glittering swarm of glass fish that divers can swim into the middle of – this is an enchanting experience that will be remembered for a very long time. Along the walls there are macro creatures like the mantis shrimp, whip coral shrimp and nudibranchs.

Picture by Ray van Eeden

On Tinga Giri, close to Hurawalhi, there is currently a large red frogfish that can often be seen fishing with the lure, which comes out from the top of its head.

What is a thila?

A thila is a deeper underwater island usually starting around 12-14 meters. Two of the Hurawalhi team’s favourite and most fascinating thilas are Anemone Thila and Fushivaru Thila.

Picture by Ray van Eeden

Anemone Thila gets its name from the incredible amount of anemones that have made themselves at home there. It is a very small thila and can be dived all they way round its circumference 2-3 times in one dive. This site is great for underwater photography and experimenting with macro photography. The most spectacular part of the dive is towards the end when divers arrive at the shallowest part of the thila and see the clownfish swimming above all the anemones along with bright blue and pink damselfish. For a good part of the year this site is also completely covered in ‘baitfish’ – so many that visibility can be reduced to 1-2 m with the fish parting to make way for the passing divers.

Picture by Ray van Eeden

Fushivaru Thila is a manta cleaning station and from November to January divers can witness the spectacular sight of the majestic mantas as they cruise in and hover over the station as small cleaner wrasse come and cleanse them of parasites. When the mantas are elsewhere, Fushivaru Thila is just as beautiful with huge schools of snappers and hunting grey reef sharks, nurse sharks sleeping under coral blocks, and large stingrays on the sand.

Picture by Ray van Eeden

There are many underwater island dive sites in Lhaviyani Atoll waiting to be explored. In Part 2 of the Dive Site Topography series all will be revealed about the differences between East and West sides of the Atoll.

 

PADI’s guest blogger Paige Bennett introduces herself:

I am an American Scuba diving instructor who has been living in the Maldives for the past 2 ½ years. I have been travelling and working for the past 6 years and have been to Koh Tao Thailand, Playa del Carmen Mexico, Marsa Alam Egypt and have now settled in the Lhaviyani Atoll working with Prodivers Diving center. I love the abundance of textures and patterns in the ocean and am very interested in underwater macro photography. I also have been involved with several conservation/restoration projects such as ReefCI in Belize, Eco Koh Tao in Thailand, and the coral transplantation project for the 5.8 undersea Restaurant on Hurawalhi Island Resort.

 

Paddle against Plastic

On Global Recycling Day, Sunday 18th March 2018, a team of our best watermen and women from Gili Lankanfushi completed a 14km Stand Up Paddle to raise awareness about the overuse of single-use plastic. During the endurance event, the team collected all floating litter they encountered along the three-hour paddle. The majority of the haul was plastic, so our message is clear: If we can SUP 14km around our island; you can give up using single-use plastic in 2018.

At Gili Lankanfushi, we encounter a large amount of ocean plastic arriving with the tide every day. Some arrives with the current from distant countries, but a lot appears from neighboring islands and the capital Male. Despite Gili’s No Plastic Policy and the plastic recycling program we have in place with Parley, we still face a tidal wave of plastic over the year. Our team wanted to tackle this problem head on.

The event began at day break as we hit the water at 7:15am stocked up with high energy food, water and cameras. The conditions were extremely favourable with low wind, little swell and high cloud cover. The first quarter of our paddle took us against the current, so it was slow going but this allowed us to collect as much floating plastic as possible. We found the majority of marine litter in the corners of Himmafushi Harbour so we set about collecting as much as we could carry. Those working at the harbor watched us approach and a few men jumped into action and helped us collect plastic from the water. They gave us a few extra bags when we ran low. These positive reactions made our hard work feel extremely valuable.

As we turned the corner behind Himmafushi Island, we had the wind and current with us, so we completed almost six kilometres in just over an hour. Being out on the open ocean and looking down to see the fish and coral beneath our feet was a real highlight. The final paddle back to Gili was the hardest, but we were met with the smiling faces of the rest of our team.


The entire experience was a great example of perseverance and team work. It was a great success and we were able to recycle a lot of litter, yet the overwhelming feeling was that we need to do even more next time. In just three hours we collected 200 items which included 90 plastic bottles, 20 bottle tops and 5 plastic bags and this was just the plastic we happened to paddle close to; a lot has been waterlogged or broken down and is found just below the surface or on the ocean floor.
The seven-man paddling crew was made up of Beau, Tropicsurf Manager and SUP surf champion; Naseef, Ocean Paradise Dive Instructor and marine mammal magnet; Emma, Assistant Marine Biologist and official team photographer; Tula, Head of Security and pretty much the toughest guy I know; Ibrahim, Ocean Paradise Boat Captain and life saver; Clare, Marine Biologist and event organiser and Jinah, Hotelier journalist and newly inspired sustainability supporter.

Despite the obvious challenges of reducing ocean plastic, we have seen such positive reactions to our war on plastic at Gili Lankanfushi. After visiting in November 2017, the inspirational Merle Campbell kindly shared:

“For many years now, I have daily walked the beach and never picked up any litter. Since visiting Gili Lankanfushi Maldives and listening about the importance of keeping plastics out of the waterways, I now walk the beach solely for the purpose of collecting rubbish to contribute to saving our sea life.”
We hope our Paddle against Plastic will inspire others to reduce their plastic dependence by taking small steps to reduce plastic use at home or at work. If we all participate, there will be a huge reduction in the amount of plastic that enters our oceans. Well done to Gili’s Paddle Against Plastic Team and Happy Global Recycling Day to Everyone.


A special thank you to everyone who assisted us in the Paddle Against Plastic! Thanks to Ocean Paradise for the boat, equipment and crew, the culinary department for the amazing food, the Sales and Marketing department for sharing our work and getting up early to see us off, the gardening team for recycling our plastic, Shifzan for the awesome photos, and the Gili Lankanfushi Management team for their amazing support!

 

PADI’s guest blogger Clare Baranowski introduces herself:

I am a marine zoologist from the UK who has worked throughout the tropics researching mega fauna and reef ecosystems in the Caribbean and Indian Ocean. I have experience monitoring and restoring coral and surveying manta, turtle and dolphin populations. I began my career as a science communicator before moving into research and management roles, this is why I incorporate outreach and education into every project I work on and I hope to continue this at Gili Lankanfushi

Earth Hour

Earth Hour is an annual worldwide movement to encourage individuals, communities, and businesses to conserve our resources. Celebrating it is a symbol of our commitment to our planet.

At Gili we celebrated Earth Hour on March 24th with the rest of the world, we hosted a Coral Conservation themed day with multiple events leading into each other. For each event, all guests and hosts were invited to attend and take part.

Our first event was a coral workshop hosted for Marine Biologists and enthusiasts. In attendance were three participants from our local island Himmafushi who have a keen interest in protecting their reef and inspiring locals. Additionally, Marine Biologists from Four Seasons Resort, Bandos Resort, Atoll Marine Centre and Hurawalhi Resort attended. Jinah, a journalist from Hotelier Maldives covered our event celebrations.

Our coral lines project launched in 2014 and currently has 190+ lines, each containing around 50 coral fragments. The aim of the project is to rehabilitate our degraded house reef through direct transplantation of mature corals and through indirect coral spawning from the nursery. The project was the first low-tech and high efficiency coral recovery project that involves rope in the Maldives.
Due to the optimal location and care that goes into the project we had 68% survival after the El Nino event and the crown of thorn starfish outbreak. Due to the success of our project, many Marine Biologists are interested in learning more as they want to launch their own projects or further their current projects in other locations. This is why we invited them to join us in celebration of Earth Hour.

 

We felt that hosting a coral conservation themed day would create a platform for a discussion on possible project improvements and new project ideas. Overtime the coral line nursery will contain heat tolerant coral species, fragmenting these species and planting lines could lead to natural spawning of more heat tolerant species which will increase survival rate in future warming events. This will lead to the creation of more healthy reefs decreasing the pressure of predation, providing a healthier habitat, refuge and nurseries for marine organisms like turtles, juvenile fish and other fish species as well as conserving a key ecological ecosystem.
On the day the visiting Marine Biologists arrived at 14:00pm and a land based presentation was carried out, topics included an in depth overview of the project, project creation, management, challenges and future plans. This was followed by a practical demonstration of making a coral line, monitoring the lines and general maintenance including cleaning and removal of invasive species. To view the coral line made by the Marine Biologists click here. To conclude there was a group discussion on possible project improvements and a question and answer session.

 

Following the success of the coral workshop together with guests, Marine Biologists and hosts we designed and created a coral shape in the sand on Library Beach. In celebration of the official Earth Hour which is between 20:30 – 21:30 we turned off none essential lights and filled the coral shape with sustainably sourced candles – coconuts and used cooking oil. During the official event our coral shape was beautifully illuminated by flickering candle lights and guests, Marine Biologists and hosts were able to enjoy this display whilst attending our Earth Hour cocktail evening.

 

To conclude our Earth Hour celebrations we hosted the documentary Chasing Coral in our Jungle cinema and Host Village. Chasing coral is a fantastic documentary about a group of divers, photographers and scientists who set out on an ocean adventure to discover why the reefs are disappearing and to reveal the underwater mystery to the world. They found that coral reefs around the world are vanishing at an unprecedented rate and documented their discoveries and explained them in a way that is accessible to everyone.
Overall the event was a huge success with all participants learning something new and being inspired to help conserve our resources. We hope that you will join us in celebrating Earth Hour next year!

PADI’s guest blogger Emma Bell introduces herself:

I am a marine biologist and scuba diver from England. I have had the privilege of working in Greece, Seychelles and Maldives. I have worked in an aquaculture research centre where I focused on hormonal manipulation of a pelagic fish species. In addition, I have experience with coral restoration projects including frames and ropes; habitat restoration – crown of thorns, drupella and invasive plant species removal; educational activities and social media updates including blogs. I have also monitored population dynamics of bird, turtle, shark and cetacean species to aid in their conservation. I started my career working in the Maldives and I have done a round trip via Greece, England and Seychelles, I hope to increase my skills set and knowledge further whilst I am at Gili Lankanfushi, Maldives.

Green Sea Turtles hatchlings on Kuredu

Guests at Kuredu Resort recently had a very cute surprise in the sand: a green sea turtle nest hatched! Late in the evening, while walking back to their villa, the guests spotted the tiny turtles making their way quickly across the beach into the ocean. A few hatchlings wandered astray and were collected by resort staff, soon to be released under the supervision of resident Sea Turtle Biologist, Stephanie, along with volunteers from the Prodivers Team.

According to previous reports, it takes green turtle nests 49 to 62 days to hatch here in the Maldives, but the baby turtles on Kuredu were a little slower – it took them 64 days to make their way out of the nest.

To evaluate the hatching success of the nest, Stephanie and a volunteer digging team from Prodivers went to exhume the nest 48 hours after the hatching event. After quite some digging, they successfully discovered the nest and out of 105 eggs laid, only three had failed to develop – that’s 102 more baby green turtles in the ocean! Such a successful nest is great news for the sea turtle population and we hope to see some of the hatchlings back on Kuredu to nest in about 10 to 15 years’ time.

Snorkelling or scuba diving at Kuredu Island Resort Maldives gives a very good chance of seeing turtles – the island is blessed with a large community of green sea turtles that can be seen at Caves, either on a Prodivers snorkelling excursion or dive trip. Turtles can also be spotted grazing in the lagoon.

Want to learn more about turtles? Visit Stephanie at Kuredu’s Marine Center and join her snorkelling on the reef for a turtle tour while she collects valuable data for the Olive Ridley Project.

Common crabs encountered in the Maldives: Part 2

Crabs are an underappreciated species. Whilst living in a harsh and arid environment they dedicate their lives to keeping the beach pristine.

Swift-Footed rock crab Laura Pola

Swift-Footed Rock Crab

The swift-footed rock crab can easily go unnoticed due to its elusive behaviour. It inhabits rocky shores at mid to high tide level and so can be found around beach rocks, boat ramps, rock walls and jetties. These crabs are fast moving and are generally only seen at night, unless disturbed. Then you may observe them jumping from rock to rock trying to find a new refuge.

Their colouration can be mesmerising with a multitude of blue, green, purple, orange, white and black. The crabs encountered on Gili are more blue, green and purple with white stripes. The shell (carapace) can be up to eight centimeters wide and is flattened, compared to other crabs which have shells that are more rounded.

Swift-Footed Rock Crab. Picture by Laura Pola

The crab feeds on algae, detritus, small vertebrates, barnacles, limpets and snails. They use their claws to break into the shells of other animals and to tear off pieces of their prey to be transferred into their mouth. This species is predated upon by a variety of animals including birds, octopus and fish, so it isn’t safe for them in the ocean or out of it!

Fiddler Crab. Picture by Carly Brooke

Fiddler crabs

Fiddler crabs are a small and short lived species of crab (up to two years) and are closely related to ghost crabs. They are found in mangroves, brackish water, mud flats, lagoons and swamps. The colouration of the crabs change in correlation with circadian rhythm – during the day they are dark and at night they are light.

Fiddler crabs are well known for their sexual dimorphism – the male’s major claw is much larger than the females. If the large claw has been lost the male will develop a new large claw on the opposite side, which will appear after molting. The female’s claws are the same size. The crabs use their claws in communication, courtship and combat. The male claw is used in waving displays which signals to the female that they are ready to mate. A more vigorous waving display indicates a healthier male and a larger claw indicates a wider burrow which will provide better temperatures for egg incubation. Females chose their partners based on claw size and the quality of waving. Once a female has been attracted she will reside in the male’s burrow whilst the eggs are being laid. The female will carry her eggs on the underside of her body for a two week gestation period. After this period the female will venture out of the burrow and release the larvae into a receding tide.

During feeding the crabs move their smaller claw from the ground to their mouth. This movement looks like the crab is playing the smaller claw like a fiddle – hence the name, fiddler crab. The smaller claw is used to pick up the sediment which is then sifted through in the crab’s mouth. Algae, microbes and fungus are the preferred diet of the crab. After the nutrients are extracted the sediment is placed back onto the ground in a ball. The feeding habits may play a vital role in preserving the ecosystem as they aerate the soil. The fiddler crab can be seen when visiting local islands, especially in the mangrove area at low tide

PADI’s guest blogger Emma Bell introduces herself:

I am a marine biologist and scuba diver from England. I have had the privilege of working in Greece, Seychelles and Maldives. I have worked in an aquaculture research centre where I focused on hormonal manipulation of a pelagic fish species. In addition, I have experience with coral restoration projects including frames and ropes; habitat restoration – crown of thorns, drupella and invasive plant species removal; educational activities and social media updates including blogs. I have also monitored population dynamics of bird, turtle, shark and cetacean species to aid in their conservation. I started my career working in the Maldives and I have done a round trip via Greece, England and Seychelles, I hope to increase my skills set and knowledge further whilst I am at Gili Lankanfushi, Maldives.

Common crabs encountered in the Maldives: Part 1

Crabs are an underappreciated species. Whilst living in a harsh and arid environment they dedicate their lives to keeping the beach pristine.

The Maldives is rich in life and biodiversity, but the majority of this diversity is marine based. Due to the great distance of the Maldives from large land masses there are relatively few land based species. Crabs, are one of the most common. These shy little critters are abundant, entertaining to observe and vital to the island’s survival.

Hermit Crab. Picture by Laura Pola
Hermit Crab. Picture by Laura Pola

Land Hermit Crabs

Land hermit crabs are completely adapted to life on land, living under leaf litter or in other sheltered areas. A common error made by people is completely submerging these crabs in water, mistaking them for marine animals. Unfortunately hermit crabs can only survive for a few minutes when completely submerged. They are not true crabs because they do not have their own shell. Instead they use shells from dead gastropods in order to protect their soft abdomens. They are a long lived species – sometimes reaching the age of 40 years and older – so they go through a lot of shells!

Hermit crabs start their lives moving through a variety of larval stages whilst floating in the ocean. The larvae spend the first 40 – 60 days of their life alongside plankton until they change into a hermit crab/lobster shape. In this final larval stage they find a small shell and over the period of a month will spend more time on land until they finally molt and leave the ocean for good. By feeding on vegetation, insects, detritus, other smaller hermit crabs and microbes in the sand the crab grows in size. To accommodate this growth their hard exoskeleton must be shed periodically during the year and this process will carry on through-out the hermit crab’s life. As they grow in size the hermit crab molts less frequently and the molt process takes longer, during which time the crab will stay completely submerged in the sand.

When sexually mature the male will knock on the female’s shell to signal mating. Both genders will then extend out of their shells and the male will fertilise the female. After fertilisation the female will carry her eggs around on her abdomen where they are protected from predation. The bigger the female the larger the quantity of eggs. After one month the eggs are fully developed and the colour of the egg will have changed from brick red to grey. To hatch the eggs the female will enter the water at low tide. Upon contact with water the eggs burst open and the larvae are released.

Ghost Crab. Picture by Hans Hillewaert
Ghost Crab. Picture by Hans Hillewaert

Ghost Crab

Another common crab species is the ghost crab which is aptly named due to its nocturnal activity and sandy colouration, making the crab perfectly camouflaged into the beach backdrop. These crabs are found on sandy beaches and live in burrows. The narrower and shorter the burrow the smaller the crab. Their burrows serve a number of purposes: protection from predation, storage of their food, protection from drying out and other extreme weather conditions as well as a place to mate (although not all ghost crabs mate in burrows).

Young crabs and female crabs create burrows with sand scattered everywhere, with young crabs preferring to create burrows nearer to the water, whilst male crabs have burrows with a neat mound of sand outside – the larger the crab the larger the mound. Males produce mating sounds, squeaking noises, in a variety of ways; by rubbing their right claw on their leg, by rubbing their legs together, or by using their gill chambers, which they keep moist with saltwater.

After mating the females store thousands of eggs inside an abdominal flap. She will then venture into the sea when the eggs are ready to hatch. Since ghost crabs cannot swim the female will float upside down in the water allowing the eggs in her abdomen to breathe. Upon contact with saltwater the larvae are released and after two months return to land.

Swift-Footed Rock Crab. Picture by Laura Pola

The exoskeleton of a ghost crab is water tight, which prevents the crab from drying out in the arid and salty conditions on the beach. All ghost crabs have eye stalks with the males additionally having horns. These eyestalks enable the crab to see in any direction and can be stored in groves on their shells. The ghost crab’s eye sight is so good that they are able to catch insects’ mid-flight. They also have a well-developed sense of smell. They are very agile, capable of moving at 10mph, which makes them the fastest of all crustaceans.

Due to the erratic nature of their food supply ghost crabs are very protective of their food and will use their claws in combat displays. Male ghost crabs have one claw that is slightly larger than the other and combat is normally non-contact and ritualistic. Ghost crabs spend the majority of their day looking for food and particularly like to eat fish, seaweed, microbes in the sand, jellyfish, other crabs, snails, turtle hatchings and really anything they can get their claws on.

PADI’s guest blogger Emma Bell introduces herself:

I am a marine biologist and scuba diver from England. I have had the privilege of working in Greece, Seychelles and Maldives. I have worked in an aquaculture research centre where I focused on hormonal manipulation of a pelagic fish species. In addition, I have experience with coral restoration projects including frames and ropes; habitat restoration – crown of thorns, drupella and invasive plant species removal; educational activities and social media updates including blogs. I have also monitored population dynamics of bird, turtle, shark and cetacean species to aid in their conservation. I started my career working in the Maldives and I have done a round trip via Greece, England and Seychelles, I hope to increase my skills set and knowledge further whilst I am at Gili Lankanfushi, Maldives.

2018 World ShootOut Winner Announced at Boot Show

World ShootOut was born in 2005 with the Eilat Red Sea ShootOut. In 2011 Producer David Pilosof initiated the first online World ShootOut competition. Each year hundreds of photographers from countries around the world take part in an annual World ShootOut competition, submitting thousands of stunning images and videos, ranging from the calm lakes of the Nordic to dramatic footage of white sharks in the Gulf of Mexico. Photographers are awarded prizes valued up to $1,000,000.

World ShootOut competition winners are announced during the Boot Show, Düsseldorf, each year and in 2018 PADI, one of the proud sponsors the competition, presented Florian Fischer from Germany, with the 1st Place Prize of $1,000.

Here is Florian’s breath taking video of the Angle of the Deep.