8^th to 11^th DECEMBER 2011

Lucrezia, Rene, Guido and Gianna who had completed the previous trip to the Similans on board MV Scuba Adventure were joined by Thomas from Switzerland and Richard from Holland for the Southern trip. With supplies loaded we headed to Maya Bay, Phi-Phi where we spent the night. With the briefings completed we had our first dive on Koh Bida Nai. Captain Pu dropped us on the wall area. Amongst the group were many photo enthusiasts, so we took our time looking for macro critters on the wall area. Visability was good, so the schools of fish slightly into the blue were seen.

After breakfast we dropped in 2 groups on Koh Bida Nok as we used the dinghy. Again, the wall area was the highlight of the dive again looking for the nudibranchs, shrimps, lobsters, morays and anything that was photogenic! The sloping reef area with the carpet of anemones was home for mantis shrimps, giant morays and a school of yellow stripped snappers. The dinghy picked up the divers and unfortunately Jack, a crew member, went for an unexpected swim when he tried to get Kath out of the water.

We then headed to Koh Haa for our third dive of the day at the Cathedral on Koh Ha Yai. We dropped in directly in front of the caves. We entered cave 2 and then swam through the connecting hole into cave 3. Looking through the hole is quite a sight as the remaining divers swam through.  The light was incredible. Once in cave 3 the fun started with the photographers trying to get the silhouette shot in the cave entrance. Lucrezia was using her new camera and had some successful shots. In the swim through there was a beautiful nudibranch , which was the first of many on that dive. Going across the plateau through the whip coral garden and on to the boulder area with the beautiful soft corals was a pleasure.  The night dive was on Koh Ha Yai with Robert and Kath. The other customers decided to relax with a beer. The night dive was very tranquil and many different types of crab were seen, but the highlight was an anemone crab that was sat on top of a coral formation. Lion fish were out hunting and a giant free swimming moray gave a performance for us.

Day 2 was the highlight of the trip. The first dive was on Hin Muang otherwise known as Purple Rock due to the abundance of purple soft coral. Here we were not looking primarily for macro as the bigger picture is magical. The atmosphere on this dive site is an experience. With hardly any current it was easy to navigate without too much effort. The hunters were out and you could feel the tension as they circled the smaller fish.

The second dive was on Hin Deang, otherwise known as “Red Rock” as there are many red soft corals. Thank you to Richard, who drew the dive site map. With the sloping reef area and the vertical walls this dive site has a variety of topography. Again, a great dive with trevellies, emperors, rainbow runners, tuna and barracuda. At the end of the dive a thermocline came in as Kath, Richard, Gianna and Guido were heading to the safety stop. Then through a wall of damsel fish and fusiliers came the big boy….A whale shark about 5m in length. Richard was off like a rocket and managed to get the magnificent creature on video. Needless to say that the third dive of the day was on Hin Deang. During the briefing “X” marked the spot on the map where the whale shark had been spotted. When we descended we swam over to the area and there it appeared. Whale sharks are directional and unlike manta’s do not swim in circles, so we only had a few moments with it, but when seeing something of this magnitude every second counts!!

The 4^th dive of the day was a sunset dive on Koh Ha Neau. The current was very strong, so we were only able to swim around the rocks as it would have been endurance to get to the reef. Again we were on a mission to find macro. The boulders are covered in soft corals of different colours. This area also has many anemones that start to close at this time of day revealing their different colours including white, green, shades of blue and purple. At the end of the dive we swam up the chimney, which starts at 16m and finishes at 5m, an ideal place to do a safety stop. While we were waiting on the surface to be picked up by Captain Pu and the crew we saw a gorgeous sunset that was worthy of a photograph.  Back on the boat we headed to Phi Phi and Tonsai Bay where we went ashore for a couple of hours to have a few drinks on the beach and watch a fire show.

Day 3 and we decided that we would dive the wall not far from Maya Bay. A relaxed, chilled dive with plenty of fish and corals. We had the pleasure of a turtle towards the end of the dive. He was quite happy having his photograph taken and even posed for us!!! The last dive of the trip was on Shark Point. Good visability and little current made this one to remember. There was a promise of a Sea Horse and thankfully, Kath found it. Again, the photographers were in their element as we were the only divers on the site. The whole dive was on pinnacle one as there was so much to see. This beautiful dive site has varied marine life, huge barrel sponges, gorgonion sea fans and lots of soft coral. The scenery it’s self is stunning.

Once again, we had a fantastic trip.

Octopuses are the master of disguise on a reef. Many times someone may be pointing at apparently nothing and then as with a 3D photo and octopus appears!!!! This remarkable creature is compelling watching as it changes colour and texture. Camouflage is possible due to specialized skin cells that can change colour, opacity and reflectiveness of the epidermis. It is believed that the colour changing is a means of communicating with others and also to warn of danger. The muscles in the skin enables the octopus to alter the texture of it’s mantle so as to blend in with it’s surroundings, for example, the bumpy texture of a rock. There is also evidence to suggest that octopus living on a complex habitat such as a reef and are more active during the day have a more developed skin than the sand dwelling and nocturnal partners.

There are 300 recognised species of octopus worldwide. All are known to be venonmous, but only the blue ringed octopus is deadly to humans. Octopuses have 4 pairs of arms and 2 eyes and are bilaterally symmetric. There is no internal or external skeleton, which enables the creature to squeeze through small spaces if fleeing from predators. They are regarded as the most flexible and intelligent of all invertebrates having both having long and short term memory.  There is only one hard part of the body, this being the beak, or mouth that is found at the centre point of the arms.

Octopuses have very good eye sight and some species are able to distinguish colour. They are also able to distinguish the orientation of their body to the horizontal using two organs that are attached to the brain called statocysts. There is also an automatic reponse that keeps the eyes orientated, so that the pupil slit is always horizontal.

The sense of touch is excellent and the suction cups found on the arms have numerous chemoreceptors that enable the octopus to taste what it touches. The arms also show a variety of complex reflex actions. This is due to 2/3 of the neurons of the complex nervous system being located there. The arms also have tension receptors, so the octopus can determine if the arms are stretched out, but the receptors are not sufficient for the brain to determine the actual position of them.

This creature also has three hearts, two are branchial hearts that pump blood to each of the two gills and the third pumps blood through the body.  The blood contains a copper rich protein called hemocyanin, which is effective for transporting oxygen in cold conditions and environments where there is low oxygen pressure. The protein is dissolved in the plasma and gives the blood a bluish colour.

The life expectancy of the octopus is short from 6 months to 5 years. The death of the octopus is genetically programmed and results after reproduction. The male of the species may live for a few months after mating, but the female will die shortly after the eggs are hatched.  During reproduction the male will insert a specialised arm called a hectcotylus into the female’s mantle where it deposits spematophore (packets of sperm). Some species can keep the sperm alive inside the female for a few weeks until the eggs are mature. Once fertilization occurs the female will lay her eggs, which she hangs in strings from her lair or individually on the substrate. This varies depending on the species.  A female may lay upto 200,000 eggs. The incubation period is approximately a month. During this time she is the protector and will gently blows a current of water across the eggs providing them with enough oxygen. However, it is to her detriment as she will not hunt. It has been known for the female to ingest one or more of her arms for sustenance.  Once the eggs are hatched she will leave being very weak and defenseless thus dying.  The larval octopus will drift for a while in clouds of plankton where they feed. . Plankton eaters such as mantas and whale sharks are obviously a threat to the larvae. When they are ready they will descend to the ocean floor.

Octopuses move by crawling on their arms or by swimming. They swim in a horizontal position with the arms behind. Movement is by expelling a jet of water from a contractile mantle. This is one of the primary defense mechanisms as they are capable of fleeing at great speed. Another form of defense is the use of thick blackish ink, melanin, which is dispersed in a cloud. It is believed that the ink reduces the olfactory organs of some hunters that hunt by smell, for example, sharks. It is also known that an octopus is capable of detaching an arm as a distraction when under attack.  The mimic octopus is highly flexible and is able to change shape to look like other creatures. It has the capability of changing to look like a more dangerous creature than the one that is attacking.

These remarkable sea creatures are worthy of watching while on a dive. If you are lucky enough to see one then do not get too close as the octopus will hide in crevices and cracks in the substrate. It is better to observe from a distance away and slightly elevated. Be patient and wait motionless. The octopus will eventually gain confidence and gradually come out into the open for you to enjoy the moment!!!!

If you would like to know more about the identification of species why not sign up for on a  Underwater Naturalist Specialty Course, which will enhance your knowledge and highlight the key things to look for, or a cruise on board MV Scuba Adventure or MV Scuba Fun for a chance to see these for yourself.

I was very excited to take this trip out during the “summer season” as tour leader on MV Scuba Adventure. All season the local sites from Phuket had been performing so well, with lots of great visibility dives and an abundance of marine life both (very) big and small. I also knew that during the high season the dive sites of Hin Deang and Hin Maung are awesome, but I didn’t know what to expect from a trip this time of year?

Scuba Adventure

… It was not a disappointment!

So here we go:

Day 1:

Shark Point – Great visibility to enjoy all the lovely soft corals, fans, sponges and tons of marine life including the odd leopard shark. Hi-light of the dive: a large marble patterned tiger tail seahorse.

Shark Point

Koh Bida Nok – Again tons of marine life, especially the trevally and schools of fusiliers, and a nice big hawksbill turtle at the start. Hi-light of the dive: absolutely the 10-20 black-tip sharks seen during the dive, especially getting up real close to 5-10 of them in the bay, before they finally torpedoed passed us.

Koh Bida Nok

Koh Ha Yai – A beautiful late afternoon dive to enjoy the caverns (known as the Cathedral) and swim-through’s. Hi-light of the dive: the view looking out at the silhouetted divers the from the back of the Cathedral.

"The Cathedral"

Koh Ha Lagoon – A comfortable night dive in the protected lagoon between islands 2 and 4. Our group explored the east side wall of island 2 and the sloping reef between. Hi-light: For me the macro life amongst the vivid soft corals on the wall, for others the giant barracuda following us!

Day 2:

Hin Muang – Oh my God! The visibility! We could see the bottom… and which ever side you are on, it goes down a very long way! Lot’s of life; and the soft corals looking bigger and more colourful than ever. Hi-light of the dive: All of it, in stunning visability. It was like a scene from the movie The Abyss but with the lights on! Diving – the best reason in the world to get up with the sun.

"Stunning Visibility"

Hin Deang – Awesome vis continued, we could even see the outer pinnacle from the main rock! Whichever way you looked there was marine activity and mild currents meant an easy swim to appreciate it all. Hi-light of the dive: Did I mention the large manta ray that made it’s way around the rock to the outer pinnacle!

"Manta Ray"

Koh Ha Neua – An early afternoon dive made the best of the huge purple soft corals on the southern side of this site. The shallow hard coral reef at the end of the dive was full of fish, whilst weaving in and out of the soft-coral coated rock channels rewarded us with nice nudi’s and a brilliant yellow tigertail seahorse. Hi-Light of the dive: A spotted eagle ray hovering over the purple soft coral field.

"Sea Horse"

Koh Bida Nok – With the currents reversed and an exciting dive the day before, we chose to go again from the other side of the island. This dusk dive showed us some more big fish (black-tip sharks), kuhl’s rays, mantis shrimps, morays, nudibranchs. Hi-light of the dive: I guess taking the time to see all the things we hadn’t noticed on the other dives – Bida Nok is one of the richest and most varied dive sites. Oh, and it being a dusk dive so some of us could visit Phi Phi Don and enjoy an evening on land.

Day 3:

Koh Bida Nai – Yet another sunny day, this early morning dive provided more sharks and a small school of big pick-handled barracuda. Hi-light of the dive: Swimming through the hundreds of fusiliers and trevally that hang out in the sunshine over the beds of stag horn coral, then back up the reef to the glittering chevron barracudas.

Koh Bida Nai

Anemone Reef – Of course anemones but also lots of colorful soft corals make this a beautiful pinnacle in good visibility… and it was! A turtle, lot’s of fish, little current, nudi’s and a few bamboo shark made it even better. Hi-light: A pale-yellow seahorse out in the sand (I like seahorses!)

Anemone Reef

Koh Doc Mai – A nice surprise… an extra dive thrown on to the end of the trip! This wall dive is awesome for macro – wonderful nudibranchs, ornate ghost pipefish, more bamboo sharks, all sorts of morays, this site can have it all. Hi-light: We got to dive again, ha!

Koh Doc Mai

Apart from the great visibility and relaxed diving (with it’s heart racing moments – sharks, manta, eagle ray), for me it was the wonderful variety of dive sites and marine life that made the trip one of the best. Also helping to make the diving awesome was that, during most of the trip, we were the only boat diving the sites… well, we were on the Scuba Adventure!