The Magical World of Christmas Tree Worms
Want to enjoy a little bit of Christmas on your Thailand travels? Then try scuba diving on Koh Tao and we will show you a little creature that look just like a Christmas tree! They might live far away from Lapland, but these colourful worms are full of festive spirit.
These cool little creatures, worms to be precise, stand out amongst the corals due to their magnificent colours ranging from reds, oranges and yellows to greens and blues.
One Family – Spirobranchus Giganteus
Aptly named Christmas tree worms (Spirobranchus giganteus), they are commonly found in large groups that have embedded themselves into hard corals such as porties and brain corals. With Koh Tao having an abundance of hard corals you cannot fail to come across them when scuba diving or snorkelling here.
For many new divers on their first dive, whether a discover scuba dive or training dive from the PADI open water course Christmas tree worms contribute to the kaleidoscope of colours that makes up the lasting memory of our first underwater experience. On Koh Tao, we are fortunate to have dive sites such as Aow Leuk and White Rock which have amazing coral patches, all covered in Christmas tree worms.
Besides being a cool thing to see when beginning your scuba diving life, Christmas tree worms make great subjects for underwater photography for the more experienced diver.
Anyone who has been diving or snorkelling on Koh Tao will tell you that these small creatures are lots of fun to watch. Even though they are small, growing to around 1.5inch/3.8cm they are very easy to spot. They make the reefs so colourful and striking to view and provide divers with some interaction and fun.
Incredibly shy and nervous creatures, any sudden water movement close by will cause them to suddenly and quickly retract back into their little holes to hide. After around 30 seconds or so they will slowly re-emerge and stand proud again on the reef. This is easily demonstrated by slowly moving your hand above the Christmas tree worms.
Over 8,000 Species
The 2 spirals that give the worm its “tree” like appearance are specialised appendages used to catch food. The feather like tentacles called radioles which make up the spirals, trap prey and help to transport it down to the mouth of the worm. Other than using their radioles for filtering plankton for food they are also provide respiration for the worm – similar to gills on a fish.
The worms are both male and female, reproduction takes place by both sexes releasing their eggs and sperm accordingly into the sea. These are then taken by the currents and are fertilized by chance out in the open sea. The egg will then land on a piece of coral and then burrow down and secrete their tube.
The worms themselves are classed as Polychaeta worms which are amonst the oceans most common marine animals. There are more than 8,000 species in this class, populating every ocean and at all depth ranges although Christmas tree worms tend to be found in shallow waters. Polcheata worms have been spotted at the bottom of the challenge deep by robotic probes sent to the deepest known point on the Earth.
Although generally small worms, most less than 10 cm in length there are known to be some species, including the Bobbit worm that grow into 3m monsters!
One of the great things about these creatures is that they are flourishing. Their population is stable and listed as “least concern” on the conservation list. They have few predators to contend with but here on Koh Tao you may catch a triggerfish trying to suck on out of its hidey hole although this is quite a rare occurrence.
Unfortunately, as with most living creatures their main threat comes from human beings and specifically all the pollution we produce. Global warming causes sea temperatures to rise which in turn harms and kills the coral in which these colourful worms live.
Christmas All Year Round
So, if you’re looking for some festive spirit then head for Koh Tao and try scuba diving or go snorkelling. You will be sure to see these colourful creatures, with their natural beauty, that will fill you with Christmas cheer and happiness as you blow bubbles around Koh Tao’s dive sites.
Author: Neil Davidson (PADI MSDT #294100)