Friday, September 26, 2014

Black Tip Reef Shark Breeding

We have been observing some very odd behaviour from our adult Black Tip Reef Sharks (Carcharhinus melanopterus) recently in the shallow water between the Spa and Jetty 2. Groups of up to 32 individuals have been observed within a small area being very active; chasing each other, almost beaching themselves, and making a huge commotion in the shallows! These groups are actually breeding aggregations, and we have been lucky enough to get some video footage of this very under studied event, which we have posted below! Credit goes to Sophon, our Spa Manager.

This species has black tips to all fins, most obviously the dorsal and caudal fin
It's not uncommon to spot large Black Tips from the jetty!
A small shark attaining lengths of around 1.8m with characteristic black tips to each fin which give them their name, these Black Tip Reef Sharks are usually seen on the reef flat and near the drop off in shallow water where they feed on small boney fishes, squid, and crustaceans. Despite a conservation status allocated by the IUCN as “Near Threatened”, it is not uncommon to spot Black Tips here at Gili, whether you’re snorkeling or just strolling along the jetties. With 37 different species of shark recorded in Maldives, and no recorded shark attacks since records began, we are lucky enough to be in one of the safest places in the world for snorkeling and diving with these beautiful creatures!

The life history of the Black Tip is a little bit of a mystery, with lots of conflicting data, which mostly reflects geographical ranges. Here at Gili, we observe mating behaviour around twice per year. This year, however, I was lucky enough to witness one such event from start to finish first hand! The sharks began to aggregate in water only 1m deep at about 10am, moving very slowly between each other at first, and building in numbers over a period of about 45 minutes. After approximately 1 hour, I could clearly see males following females very closely, attracted by chemicals she releases. All the sharks began to swarm quickly into a smaller area, where I could count ~32 within about 20 square meters!! After this courting behaviour, the male sharks bite the females’ pectoral fins and push her head against the shallow sand and mating begins. It lasts a few minutes, and once complete, all the sharks disperse and continue with their usual daily behaviour: Patrolling the reef.
Black Tip pups congregate in the shallow lagoon at 
Gili Lankanfushi

Studies suggest Black Tip gestation period is somewhere between 9 and 16 months, at which point our females will give birth to 2-5 live pups.  Black Tip Reef Sharks have high site fidelity, meaning these individuals will remain on Gili’s reef for many years. We will have to check back from next June and see if we can find any small pups hiding in the shallows! In the mean time- watch out for big pregnant females!!

Monday, September 15, 2014

Over 1000 corals in the nursery!

Coral Lines nursery has more than 1000 coral
fragments now.
Our nursery marker  
We have reached a huge milestone in our Coral Lines Project here at Gili Lankanfushi! We are delighted to share with you that we just planted our 1000th coral fragment in our mid water nursery! Line number 021 was planted on September 5th by Vaidas and myself following a donation the previous week, which left us with 1044 coral fragments! We were very excited and proud to be placing our 1000th coral in the first nursery which has a 24 line capacity. With 24 lines currently placed, our first nursery section is complete, and with 1132 fragments still alive out of 1195 total corals planted it is, so far, an extremely successful project!

Planting up a coral line with Acropora humilis
Guests who donate and guests who have come to speak to us firsthand at the resort about the Coral Lines Project will know exactly what Vaidas and myself are getting up to, however, we feel this milestone provides us with a great platform from which to share with our readers here at our Underwater World Blog who haven’t seen the project in the flesh just what kind of work does go into the project.

First we have our guest experience. Upon donation, you are invited to accompany myself or Vaidas to come and plant the corals yourself! We take you to our floating Castaway, with beautiful 360 degree views of the lagoon, and choose a coral species. We then fragment the colony into small pieces and place 50 fragments inside the 5m length of rope. Each fragment is measured, the rope is weighed, and we freedive down to insert your rope into the nursery. Whilst the guest experience is one of the most important aspects of the project (without your kind donations, it simply wouldn’t be possible to pull  this project off), we also do a lot of work behind the scenes to keep your corals healthy!

So what actually goes on?

Transport cage for corals of opportunity

Freshly cleaned up Acropora vermiculata fragment
Before we go to plant the lines, there are several important jobs that must be done. Dry work includes cutting the lines to size and prepping equipment, but we must also make sure to keep a constant supply of coral colonies under the floating Castaway, ready to be fragmented. These colonies are what we call ‘Corals of Opportunity’. This means that they are naturally occurring colonies which, if we didn’t remove them from the reef, would die of natural causes. For example, an overturned table coral, or a colony that has been detached from the substrate somehow has very low chances of natural survival. Vaidas and I scout our One Palm Island Reef for any such corals, and transport them using a floating cage to a small colony nursery on the seabed below the floating Castaway, ready for our guests to choose from.

Another A. vermiculata fragment, infested by what
we suspect is a type of sponge.
Once lines have been planted, other jobs start to fill our to-do lists. Each week we clean your coral lines. Using SCUBA equipment Vaidas and myself dive down to carefully clean the lines by brushing off any algal build up with a toothbrush, and removing any animals which might bore into the coral tissue such as small clams which have begun to grow on some of the lines. This process currently takes us about 2 hours per week, but is necessary to help increase the growth rate of your corals as it means they are not competing with much faster growing algal species!

Myself and Vaidas, updating our
 Coral Lines database
As well as cleaning, every 3 months your corals are measured. As the lines hit each 3 month anniversary, Vaidas and I juggle calipers, a slate and a pencil whilst carefully controlling our buoyancy using SCUBA to measure the widest point of each individual coral on the line. Not only do we record the size of the coral, but we also subjectively monitor partial and whole fragment bleaching and mortality along with anecdotal instances of disease and creatures boring into the tissue such as sponges!

This work being complete, we head back to the desk to update our ever growing database we call the ‘Reef Library’. All the measurements and qualitative notes are placed into the Reef Library, from which we can begin to calculate all kinds of statistics. We are currently working on a report using easy to read graphics which we will make available within the next month on our Coral Lines website ( so that our readers can see what your donations are going towards, the percentage of corals in the nursery still alive, and how much all of our corals are growing through time!

We are also working on planting a purely experimental nursery… 

So keep checking our blog for updates ! 

Article written by Deborah Burn, posted on her behalf. 

Friday, August 22, 2014

New Dolphin Watching Code of Conduct

Unknown to most, the Maldives is actually one of the best places in the world to come whale and dolphin watching, with 23 different species of Cetacean (the scientific Order containing dolphins, porpoises, and whales). That’s more than a quarter of the Worlds species! The deep channels between atolls are used as a ‘whale highway’ during migrations from breeding to feeding grounds for many oceanic whale species, and Maldives is even home to the largest animal on our planet, the Blue Whale (Balaenoptera musculus)! These deep channels are only really accessible to safari vessels, so here at the resort we focus in the smaller, but no less spectacular, shoreline associated species; the most common of which is our Spinner Dolphin (Stenella longirostris).

A small species of dolphin at only 2.2m,
Spinners have a long nose and a light grey racing stripe
Characterized by a long beak or rostrum (their name in Latin literally means "long nose") with a light grey stripe down the side of their body, Spinners are famous for their incredible acrobatic behaviour. The Spinners leap from the water and rotate on a longitudinal axis. The record number of spins is 7 in 1 jump, and it is this behaviour that leaves our guests in awe of the dolphins' aerobatic beauty and strength. Through years of observation, the Maldivian people have recognized patterns in the dolphins' daily behaviour and can predict where the dolphins will be, depending on the time of day, which is what has made dolphin watching cruises throughout Maldives so successful. We can almost guarantee Spinner Dolphin sightings on a daily basis. As scientists, we have studied these bahavioural cycles closely and though our careful observations we know exactly what the dolphins are doing and why. So what have we found out?

Let's take a look at a day in the life of a Maldivian Spinner Dolphin:

As the sun begins to set and darkness falls, one of the World's most impressive migrations begins: plankton begins to rise from the abyssal depths of 2000m to around 200m. This diurnal vertical migration brings with it mesopelagic fish and squid from the depths which feast on the plankton. It's at this time, when these riches come within reach, that the dolphins split into small groups called sub-units and begin to hunt. Spinners can dive to depths of around 300m and hold their breath for approximately 10 minutes, whilst communicating with the rest of the pod using high frequency whistles. Using echolocation, the dolphins can scan the darkness and create a mental image of their surroundings using sound. Dawn is a time for play as the dolphin sub-units reunite in the channels between the islands and head inside the shallow atoll to rest in safety. Breathing becomes synchronized and more frequent as the dolphins drift into a state of sleep. As conscious breathers, dolphins cannot go to sleep completely as they would drown, so they exhibit something called uni-hemispherical sleep, which is where one side of the brain is shut down whilst the other half is awake, watching for predators such as sharks and regulating breathing. During the day they alternate the sleeping side of their brain and wake up refreshed in the evening, ready for the nights hunt.

The resorts have harnessed this in-depth knowledge of dolphin behavioural ecology to combine our dolphin cruise with the sunset, as the dolphins are most active at this time and we can predict their presence just outside the atoll. Many dolphin criuses will operate at the same time of day due to these reasons, and therefore create a disturbance to the dolphin populations. Boat disturbance is now thought to be the biggest threat to dolphin populations in Maldives. Too much boat interference can cause disruption of natural breathing and feeding cycles, whilst irresponsible and reckless boat movement can cause panic induced stress, separation of mothers and calves, and even death by collisions.

Code Of Conduct
Due to these threats and our intricate knowledge of their immense intelligence and complex ecology, a code of conduct was developed. This set of rules was developed by the resident marine biologist at Six Senses Laamu Resort, and we at Gili have also put it in place for our boat crews to follow so that we can minimize our disturbance to the local Spinner population. All of our boat captains and crew have under gone training so they not only know the code of conduct and how to effectively implement it, but they also have an in-depth knowledge of dolphin biology and behavioural ecology which helps in understanding why we implement these rules. The code includes not going too fast when in the dolphins vicinity, and not rapidly changing speed and direction so as to reduce chance of collision and reduce engine noise and vibration. Not approaching directly from in front or behind the pod and converging onto prevents the feeling of being chased, gives dolphins the choice of coming to  bow-ride, but instead converging onto their direction of travel, allowing the dolphins the choice of whether or not to come to us, avoiding chasing and splitting the pod. The more resorts who take this code of conduct on board, the more effective our efforts will be to safeguard the dolphin watching industry for future generations!

A juvenile Spinner Dolphin entertains guests whilst a pod of 50 surrounds the boat!
Alongside this eco-friendly initiative, one of our resident marine biologists is present on the cruise 4 times per week, offering a short presentation explaining a little about the life of the dolphins and why we input our code of conduct. So far, this has been received extremely well by the guests who relish the opportunity to ask the marine biologist questions about these beautiful animals whilst they sip champagne and observe incredible acrobatics on an eco-friendly cruise.

Monday, July 7, 2014

World Oceans Day 2014!

World Oceans Day on June 8th is an annual event to celebrate the World's oceans, and to show our appreciation for the goods and services the ocean provides such as seafood, medicines, trade routes, and economic revenue. It’s also a day for education; to spread awareness of conservation issues and protect these goods and services we often take for granted. At Gili Lankanfushi, I put together a program for the day, which all guests were invited to join in on. 

 All day, from 8am until 5pm guests were encouraged to come down and try out some of our exciting water sports! Kayaks, windsurfers, and paddle boards criss-crossed our lagoon throughout the day. 

The morning was filled by Marine Biologist guided snorkeling of our One Palm Island reef which included a short presentation about the fishes we were likely to see! On these reef tours, I am usually able to point out lots of cryptic reef critters our guests have never seen before, and today was no exception! We were even lucky enough to spot two green turtles during our snorkel!

Our Ocean Paradise Dive School held a Discover SCUBA Dive session in our pool for any guests interested, which was followed by a special presentation "Rainforests of the sea" delivered by myself at our Over Water Bar. The presentation covered biodiversity of reef systems, including a short snorkelers guide on the animals on our reef! We also discussed climate change and the impacts it could have on reef ecology, and how we might be able to mitigate these effects.

Our guests were given the opportunity to taste the goods of the ocean with our ocean inspired dinner menu developed by Executive Chef John Bakker at our By The Sea restaurant, which was comprised of sustainably caught seafood bought from local fishermen who use hand lining techniques which allows for very selective fishing and no by-catch! 

Finally, to round off our action packed day of ocean appreciation, underwater themed movie 'The Big Blue' was screened at Horizon Beach under the stars!

This World Oceans Day was a great success. But here at Gili, our many eco initiatives help us to conserve and protect the ocean all year round, improving our surrounding environment and allowing for incredible natural experiences! We try to make each and every day as exciting as the next when it comes to celebrating our Indian Ocean!