Marine Life

Manta Ray – Marine Life in Thailand

Manta Ray in ThailandManta Rays are one of the most popular fish that divers wish to see when they come to Thailand. Not only can they grow to huge proportions, they are also none aggressive and can be quite inquisitive too.

Manta Rays tend to like the nomadic lifestyle and are commonly found in warm tropical waters, they love to hover around deep water seamounts, which top out near the surface, feeding on the huge amounts of plankton that gather there.

The manta ray is not the solitary animal many believe it to be, they tend to gather in rather large groups at certain times of the year, especially when there is an abundance of food around -and females of course. There is a hierarchy in the order of things in Manta world.

Very often have I seen larger Mantas whether males or females, chase away and use what is threatening posture towards younger and smaller animals which are trying to move into their eatery.

In fact, with this posturing in mind, I strongly believe that I have also been victim to this rather bullying behavior, which by the way is consistent throughout the entire shark world (which incidentally Manta’s belonging too) – the largest animal in the area eats first.

During this dominant display, the Manta will approach the smaller animal very quickly flipping itself into a roll, which looks simply breathtaking and intimidating at the same time. They will also chase smaller mantas off the reef.

Manta Rays have a love for all things clean they love to frequent cleaning stations. These cleaning stations are manned usually by a crack team of cleaner wrasse and small angel fishes. These fishes swim directly up to the manta and pick away any small parasites and other growths that the manta has picked up on its travels across the oceans.

These little cleaning fish are in no danger from the manta or any other fish for that matter which use the cleaning stations, as they provide one of the most important roles on the reef. Their role is to rid these and other fishes on the reef of parasites and dead tissue.

Mantas are part of the Ray family, which is also part of the cartilaginous family of fishes; unlike many sharks they have no teeth. So to eat they must sieve the food particles out of the water using rows of tiny plates in their mouths.

This food is called plankton and is the most abundant food source in the oceans which includes microscopic plankton, small fish and crustaceans.
Even though the Manta can grow to huge sizes, it does not make them in invulnerable to predators, quite often, have we seen where mantas have lost their tails in part or even completely.

Also I have seen many Mantas that have had bite marks on them and on some occasions they actually have large portions of their wings bitten off. Presumably by large sharks such as Tigers and Bull sharks, Oceanic White Tip and other large aggressive sharks.

Female Manta Rays carry their eggs till they hatch inside their womb. A process known as aplacental viviparity, this process is quite common in rays and sharks throughout their world. After hatching, the Female Manta Ray will finally give birth to one or two young about six months later, they grow very quickly.

Manta Ray numbers like most big marine creatures are on the decline, as they are susceptible to over fishing, pollution and of course man. Manta Rays are an absolute wonder to observe, there grace and inquisitive eye are there for everyone to see – well if you are lucky enough that is to see one up close.

Manta Ray Facts

Family: Mobulidae
Genus: Manta
Common Name: Manta Ray
Scientific Name: Manta Birostris
Origin: Worldwide
Diet: Carnivore
Life Span:15 – 20 years
Conservation Status: Near Threatened
Colour: black white or grey
Habitat: Warmer tropical waters
Main Prey: Fish, Plankton, Shrimp
Predators: Sharks, Humans, Killer Whales
Distinctive Features: Plate-like teeth and enormous body

Manta Image Gallery

Marine Life

Leopard Shark – Marine Life in Thailand

Leopard Shark at Anemone Reef
Leopard Shark at Anemone Reef

Leopard sharks are also referred to as Zebra sharks, this name comes from the younger species as they are striped like a zebra, and not until they grow do they start to form the stripes on their bodies that look more like a leopards’.

Leopards Sharks here in Thailand are quite frequent visitors to our reefs, although in recent years their number have dwindled somewhat, maybe due to warmer waters, who knows. Like most sharks, very little is known about what they get up to after dark.

Leopard sharks can be found sleeping through the daytime on sandy areas around the hard coral reefs. They are found throughout the whole of Thailand, all down the Indian Ocean coast and all-round the pacific region of the country too.

These most graceful swimmers can grow to almost three metres in length; the biggest I have seen is over two metres. They can live up to thirty yrs. old, however when kept in captivity they never live much longer than 15 yrs.

These sharks are bottom dwellers and spend most of the day resting on sandy areas; they are one of the few sharks worldwide which can lie on the bottom and still breathe efficiently. They will point their nose into the oncoming current directing oxygen rich water through its highly evolved gills.

The way the Leopard shark swims is a wonderful sight to see, they have a very long tail fin (caudal fin) which they swish from side to side so elegantly making them very agile in the water.

They love nothing more than to eat small shellfish, such as crabs, shrimps, smaller fishes, they will also eat mollusks like cuttlefish and octopus as well as squid, and they also love to eat sea snakes, now this would be very interesting to watch.

Their mouths have no teeth as such, but very powerful boney plates, which have a serious shell crunching action going on. They are not at all dangerous to man, well as long as you don’t pull their tails or poke them in the eye or anywhere else for that matter. They will usually just swim away when divers get to close for comfort.

I once observed a breeding pair on the Bida Nai Dive Site of Phi Phi Island, we were quite large group of divers about seven in all, and as we approached, something (we could not see perfectly due to the visibility of the surrounding water) at around twenty metres deep, from a distance looked like a very large fish resting on the bottom. As we got nearer and nearer it became obvious what was going down.

The male had grab the female by her pectoral fin in his mouth, and had flipped her over onto her back, both of these fish were completely motionless, that was until we came into view, then I noticed them getting a little restless. I figured that we should leave them to it; nobody likes a peeping Tom, right?

The female of the species lays around ten large eggs which hatch after five months incubation. The baby Zebra sharks are round 50 cm when they are first born and have the very distinct coloured stripy pattern which I mentioned previously.

Being quite a large shark they really have few predators, although Tiger sharks and Bull sharks have been known to attack them from time to time. Generally around Thai waters anyhow, the only real threat to their existence is… You guessed it, man.

Zebra Shark Facts

Family: Stegostomatidae
Scientific Name: Stegostoma Fasciatum
Origin: Indian and Pacific Oceans
Diet: Omnivore
Size: up to 3 metres
Weight: can be up to 16-20kg
Conservation Status: Threatened
Favourite Food: Sea Snakes, Mollusks, Shellfish Fish
Habitat: Tropical waters
Special Features: Leopard spots and long tail fin

Leopard Shark Image Gallery

Marine Life

Cuttlefish – Marine Life in Thailand

Cuttlefish are one of the most intelligent, interesting and intriguing creatures on the reef is the Cuttlefish. The Cuttlefish is not a fish at all really; it is classed as cephalopod, other members of the Mollusk family are the Octopus, Squid and the elusive Nautilus.

Cuttlefish are found in most of the world’s oceans and seas, although saying that they are not found anywhere around the Americas. We know of 120 species of cuttlefish, and that they vary in size from a small 15 cm to the very largest of the large cuttlefish over a half metre in length (not including tentacles) and can weigh up to ten kilos.

Cuttlefish at Richelieu Rock, Thailand
Cuttle Fish mating

Cuttlefish are carnivorous and love nothing more than munching down on small Crabs, Shrimps, fish; they even have cannibal instincts too. It is a highly evolved predator often referred to as the Chameleon of the sea. Which is due to the way it can dramatically change its skin colour and appearance, in order, not only to defend itself but, also to hunt and confuse its prey.

This amazing little Mollusk changes colour by pigmented chromatophores, through this process the cuttlefish can use the colours, red, blue, yellow black and brown, these colours sit above a layer of reflective skin cells. The pigmented chromatophores have a sack of pigment and a large membrane that is folded when retracted.

They use this skill to fantastic effect, not only to mesmerize prey before consuming it, but to camouflage it against predators too. This wonderful light show that the cuttlefish produces also depends upon its temperament. The creature can change colour at will and does so constantly throughout the day, with different colours being produced depending on its mood at that particular moment.

They have eight arms and two longer tentacles that they use to feel and search for prey. These tentacles have highly efficient suckers which they use to secure prey before consumption. Cuttlefish have a valuable ink sack which inside contains their ink, which they can fire at will to confuse and avoid predators that may have mollusk supper on the mind.

Sepia Eye
Cuttle Fish Eye

Here in Thailand we see these amazing creatures quite frequently, such like in Similan Islands & Surin Islands. In fact it is not uncommon to see two or three of them very close together, especially if it mating time.

It is possible to get very close to them, as they are a very curious, as long as you approach slowly and never from above, you may be able to get within a few metres. If you are really lucky, like I have been on several occasions, you may witness the female laying eggs inside rock crevices.
Prior to the egg laying process by the female, she may have already mated with several other cuttlefish, each time storing the sperm until she is ready to allow the sperm to fertilize her eggs. After mating, the male will guard the female until she lays the eggs, guarding her against any other males in the area that will try and mate with her too.

When this happens it can lead to a fight between the two males, rarely is the fight won by actually scrapping, but usually after the standoff the bigger of the two males will usually posture enough for the smaller one to back down and retreat.

It is all action on the reef and in the cuttlefish world it is no different, you really need to only look them in the eye to see that there really is something going on in there looking back at you. The next time you dive and if you are fortunate to see one of them or maybe more, get as close as you can to it and just observe its action and you too will be amazed at its colorization. They truly are a fascination from the deep.


Cuttlefish Facts

Phylum: Mollusca.
Class: Cephalopod.
Scientific Name: Sepiida.
Found: Worldwide.
Diet: Carnivore.
Average Lifespan: up to 3 years.
Conservation Status: Threatened.
Favourite Food: Shellfish.
Habitat: Coral reefs and deeper waters.
Litter Size: 200.
Predators: Fish, Sharks, Cuttlefish.