Weird creature of the month – December

Manta Ray

The word ‘Manta’ comes from Spain and means cloak or shawl. 20 years ago we almost did not know anything about the world’s largest Ray. There are two kinds of Mantas and that is Manta Birostris (the giant ocean manta) and Manta Alfred (the resident reef manta). Mantas are close relatives to all kind of sharks and rays but do not be afraid! They only feed on the smallest organisms in the sea, like small fishes, shrimps and plankton. They are also very intelligent, curious and playful. They actually have the largest brain of all the world’s fishes!

A Manta can never stop swimming. If they do the water will stop flowing over their gills which is the way they breathe. So if they do stop, even if it is only for resting they will die. After a lot of research we now know that Mantas can travels long distance in a very short time thanks to their huge wings. They also go very deep down in the ocean, research found one 1372 meter under the surface.
The Manta Birostris is the largest one and can be up to 7 meters from wing-tip to wing-tip and can weigh up to 2000 kilos. Mantas can probably live up to 50 years and possibly for 100 years, we do not know for sure.

Weird creature of the month – November

The epaulette shark (Hemiscyllium ocellatum) is a species of long tailed carpet shark, found in the shallow, tropical waters of Australia and New Guinea (and possibly elsewhere).
The most fascinating thing about this shark is that it doesn’t swim! It actually walks on the bottom by the help of their fins. Only if it feels really threatened it swims just to get away. The name of this shark comes from the very large, white-margined black spot behind each pectoral fin, which are significant of military epaulettes.

It’s a small shark, typically less than 1 m long and has a small body with a short head and broad, paddle-shaped fins, two on each side. This little guy feeds on small shrimps, crabs, small fish and snails. The epaulette shark has evolved to cope with the severe nighttime oxygen depletion (hypoxia) in isolated tidal pools by increasing the blood supply to its brain and selectively shutting down non-essential neural functions. It is capable of surviving complete anoxia for an hour without ill effects, and at a much higher temperature than most other hypoxia-tolerant animals.

Sadly this shark is very common for people to have in their aquariums at home due to its size, and the worst natural enemies in the ocean are bigger fishes such as larger sharks. Hopefully there are enough sharks left in the oceans so that me and you can have the opportunity to swim with one someday.

 

Matilda Friberg
Kon-Tiki Krabi

Weird creature of the month – October

Dugong is a large marine mammal, together with manatees, they belong to order of Sirenia, which  today has only four living species.

Dugongs can weigh as much as 380 kg and reach up to 3 m in length. They can live long, oldest recorded specimen reached age of 73. They have several nick names like Sea Cow, Sea Pig, Lady of the Sea, the last one comes from the Malay word duyung. Dugongs have been on the hunters list for thousands of years due their meat and oil. Closest relative to dugong, the Steller’s sea cow was hunted down in the 18^th century. Today authorities are trying to save dugongs with different conservation and protection projects.

In some cultures they are legendary for their medicinal purposes. In Southern China catching dugong was thought to bring bad luck.

Did you know that actually dugongs are considered to be the inspiration for Mermaids?

Dugong populates more than 37 countries throughout Indo-Pacific. Biggest population you can find is from coast of Northern Australia. The sea of Trang province in the Andaman Sea is home to dugong as the area is rich with sea grass.

Dugongs have few natural predators, although animals such as crocodiles, orcas, and sharks pose a threat to the young.

Dugongs are called as “sea cows” because their diet consists mainly of sea-grass. Occasionally they eat jellyfish, sea squirts, and shellfish. Dugong can spend all their life in sea water, without having need for fresh water.

Due to their poor eyesight, dugongs often use smell to locate edible plants. They dig up an entire plant and then shake it to remove the sand before eating it. Sometimes they collect first a pile of plants before eating it. The muscular upper lip is used to dig the plants out, witch leaves furrows in the sand in their path. They may travel long distances to find food. As they need a lot of sea grass then usually we can’t find many dugongs in the same area. They spend most of their lives solitary or in pairs.

Dugongs may stay under water up to six minutes, dive down to 39 meters, but most probably you can meet dugong at depth of around 10 meters. Most of the dugongs in Thailand we can find in Trang province (2013 about 110-125 individuals), where a much smaller population lives in Gulf of Thailand.

Weird creature of the month – September

The name “Bobbit worm” was puplished in the 1996 book “Coral Reef Animals of the Indo-Pacific”, in reference to Lorena Bobbit, who was charged for cutting of her husbands private parts. The name is inspired only by the scissor like jaws of the worm.

The Bobbit worm is an aquatic predator with a lot of bristles. It lies at the floor of the warm tropical oceans of the Indo – Pacific and warmer regions of the Atlantic. This organism buries its long body into an ocean bed composed of gravel, mud or corals in shallow water. Here it waits patiently for a response to one of its five antennae, attacking when it senses a prey. Armed with sharp teeth, it is known to attack with such speeds that there is no escape and the prey is sometimes sliced in half. The worm hunts for food at night and eats everything from small fish, corals or seaweed up to larger aquatic predators.

The Bobbit Worm injects a narcotizing or killing toxin in their prey animal, so it can be safely ingested — especially if they are larger than the worm, like a Pacific lionfish http://www.youtube.com/watch?v=3H4J5QDQeA4.

The worm can even harm humans, since the toxin can cause permanent numbness.

Unlike a different family of worms, the fire worms, which have harpoon-shaped bristles that release a toxin that can cause severe skin irritation, the Bobbit Worms specimens bristles are not used for defensive purposes. They simply use their bristles for improving traction for crawling over the sediment or inside their galleries or tubes.

Little is known about the sexual habits and lifespan of this worm, but researchers hypothesize that sexual reproduction occurs at an early stage, maybe even when the worm is about 100 mm.

100 mm is very small, considering these worms can grow to sizes of nearly 3 meters, although the average length is 1 m and 25 mm in diameter.

Bobbit worms may accidentally be introduced into artificial environments. In March 2009, the Blue Reef Aquarium in Newquay, England, discovered a Bobbit worm in one of their tanks. The workers had seen the devastation caused by the worm, such as fish being injured or disappearing and coral being sliced in half, but did not find it until they started taking the display apart in the tank. The worm was nicknamed “Barry”.

Weird creature of the month – August

Gobies is by far the largest family of fish with approximately 1,500 known species over the whole world. Just like its near relative the blenny, the goby usually lives in burrows and holes and are territorial, were most species are around 10cm in size.

The goby is a relatively social animal that lives with its partner for a longer period. The male goby attracts the female by making noises, and it is proven that these sounds are crucial for the choice of partner. The sound is made by the male gathering an amount of water in the mouth and quickly spurting it out with a massive force.

Another very interesting feature many of the gobies have around our dive sites is their partnership with shrimps. They live in a symbiotic relationship and depend on each other for survival. The shrimp is very skilful in digging, finding food and making a burrow. However, since it is blind, it makes the shrimp a very easy snack for predators.

The goby on the other hand, has very good eyesight but lacks the skill of digging, hence also making it an easy target. To survive they work together with the shrimp where the fish sit outside the excavation site as a lookout.

If you look carefully at the shrimp you can see the tentacles in close contact with the goby. If a predator would close in the shrimp can wiggle the tail, alarming the shrimp. The shrimp will then move to the side so the fish can swim in and hide.

If you avoid exaggerated movement and breathe carefully, you can see the shrimp and the goby on the sea floor all over Phi Phi Islands and Koh Haa.