One of the philosophies that is central to our work here at the NHRCP, is the preservation of the genetic diversity of our coral reefs. Koh Tao’s reefs are beautiful and diverse ecosystems. containing a wide variety of different coral species and growth forms. The emphasis that we place on the understanding of coral taxonomy helps our team of conservationists gain an appreciation for the genera of coral that are less abundant on our reefs, encouraging the protection of these marginalized species.
For many years we have been visiting and monitoring the Blacktip Reef Shark Populations in Shark Bay, starting with the work of Shin Arunrugstichai during his time on our team. In February of 2015, we restarted that program, and have been monitoring the abundance and population dynamics of the sharks with improved techniques. During each survey, we record the position of the shark with a GPS, and also take data on the size, sex, and behavior. The idea was to look at the movement of the sharks pre- and post-spawning, with particular emphasis on the neonates or new born shark pups. What started as a weekly survey quickly turned into a few times a week, and then everyday once the spawning started. The high level of surveys meant that we were able to involve all of the interns and students within the program, and show them how to monitor these shark numbers. These surveys also gave the students an opportunity to learn how to survey and observe sharks in their natural environment, and how to identify the age and sex of the shark.
Within the realms of biology lies an underlying skeleton that allows the very heart of the science to thrive, this being the concept of classification. The organisation and categorisation of different organisms can be based on type, size, and any number of variables and characteristics, each with its own crucial importance to research to the most detailed level, and to the largest biological questions of all. This skeleton is comprised of many parts, and at its very backbone, lies the concept of taxonomy, used as the most common form of classification. Taxonomy is the classification system by which organisms are divided into phyla, families, species, etc, and rely strongly on the variation in the internal anatomy of organisms and in modern analysis, differences in the genetic makeup between organisms, i.e, DNA. You can learn more about a taxonomic approach to classification in our introduction to key invertebrate species of Koh Tao and the Gulf, in our learning resources section here.
The 2015 season continued to drive the NHRCP as an institute of research as well as conservation. During the season, eight manuscripts in particular were completed that are highlighted below. The research topics range from new discoveries in feeding of corals, to assessment of health and threats to the coral reefs of Koh Tao, and even an analysis of isotope prevalence that provided some very interesting results. Below you can see a summary of those papers, and also click on the links for more information or to download the PDF of the paper.
Giant clams, Tridacna Sp., are not widely known by the every-day tourists. Three different species occur at Koh Tao; Tridacna maxima, Tridacna squamosa and Tridacna crocea. Although giant clams are not widely known, they can easily compete with the rest of the coral reef in a beauty competition due to their stunning camouflaging coloration. Moreover giant clams live up to their name and can reach impressive sizes, the largest species in this genus reaching up to 1.4 meters! At Koh Tao however the largest individuals grow up to a more conventional 40 cm.
Giant Clams get hold of food in two different ways. The first source of food for giant clams is zooplankton, which are obtained through filter-feeding, this is the main food source for giant clams in their early stages of life. Giant clams also have a symbiotic relationship with a unicellular algae (called zooxanthallae), which live in the tissues of the clams. These algae share some of the sugars and carbohydrates they produce, through photosynthesis, with the clam. Not only does the zooxanthallae provide about 90% of the clams daily energy budget, they are also responsible for the clams unique and ornate coloration.
In normal, human, terrestrial, domestic urban or rural life, the concept of a chimney is nothing special to people. To some, the romanticised idea of a warm fireplace, to some bringing about thoughts of Christmas, and others simply curiously wondering at such ancient forms of energy acquisition. On a larger scale, like in industry, chimneys are seen as a symbol of pollution and chemical toxicity, with factories pumping clouds of black smoke into the atmosphere to produce whatever they produce. Or even larger icons of destruction, are the monstrous chimneys of Nuclear Powerplants, massive funnels billowing steam reminding us of scale of energy contained and being produced within the facility.
This design, to eject masses of by-products into surrounding environment, long pre-dates human thinking. Coral reefs around the world are filled with its own chimneys, often well over the height of the tallest ape and sometimes several meters in circumference, Barrel Sponges are the towering columns of the marine world. These structures are some of the simplest, and are descendants of some of the oldest forms of life on our planet, and they serve an often overlooked role in saving coral reefs. Above the waves, chimneys direct waste gasses into the air above to dissipate over a wider area and the same mechanism is utilised by the barrel sponge on coral reefs. The reefs of Koh Tao have a diverse range of sponges but none are more impressive and dominating the reefscape than the Barrel Sponge (in this case, Xestospongia testudinaria).
Throughout the past several years, the program has been conducting ever increasing amounts of research on the invertebrate organisms of the island. In 2012, our research expanded into the complex and charismatic world of the nudibranchs, and shortly after, the remaining sea slugs. In December 2015, the program published the findings of the research in the journal Marine Biodiversity.
Sea slugs are an incredibly diverse and fascinating type of organism that are found in marine environments worldwide. You can read more about sea slugs and the roles they play in our learning resources segment here. At the program, sea slugs play important roles in two of our key activities, beyond the incidental observations doing restoration work. The first of these is the inclusion of nudibranchs (and by extension the rest of the sea slugs) in our Ecological Monitoring Program (EMP) surveys which you can read about here. The second is the significance of sea slugs in our muck exploration efforts which have led to a number of interesting findings. In 2012 the research started out mapping the inventory of all known species of sea slugs found on Koh Tao, almost 3 years later the findings of the research came to a number of interesting and regionally significant conclusions.
It was a momentous week for us here at the NHRCP, as we sunk 3 of our newest sculptures in Chalok Baan Kao on the subject of ‘Despair’. This was, in no small part, due to the efforts of our incredible team of volunteers, interns and staff. Without them, none of these concepts would ever come to fruition and I can’t thank them enough for their continued support.
Restoration work has already begun on the sculptures, as fragments were transplanted to their surfaces using epoxy. Acropora corals were chosen for the bases of the structures while slower growing sub-massive species (Porites, Favites, Goniastrea, etc.) were planted onto the topmost surfaces. The faster growing branching species of Acropora will create a wealth of structurally complex habitat around the bases of the structures, while allowing the sub-massive corals time to mature without the risk of being shaded.
The Crown of Thorns Starfish, Acanthaster Sp., is a large sea star whose diet consists almost entirely of hard corals. This sea star has been known to cause devastating losses to coral reefs in areas where their populations rise, or where corals are particularly stressed by other threats such as development, over-fishing, physical damage, or bleaching. For years, we at the NHRCP have been monitoring Acanthaster populations around our island, and performing removals in areas where populations are relatively high, or coral levels are low. In 2014 we removed 138 individuals from reefs around our island, and in 2015 we removed over 277. After so many removals we started to wonder where the new sea stars are coming from, what depths are they living at, what are the population dynamics, and what corals do they prefer to eat. All of these points where investigated in detail by one of our interns, Leon Haines.
Each year, we are blessed to receive many people coming to Koh Tao to assist on our marine conservation program from all ages, countries, and demographics. Yet, we are always surprised at how little those involved in the rest of the diving industry actually do to protect the environment, and the same goes for society as a whole. Is there something unique about these people who come to dedicate weeks or months of their lives to helping the sea? What could it be about their personalities, life history, or character that makes them put the wellbeing of others, or the environment, over their pursuit of other things. Or, more importantly in terms of changing the future; why do so many people not get involved in humanitarian or environmental projects. How is it that they can overlook the suffering of other humans, animals, or entire ecosystems and do nothing?
For the most part, it is not because they lack empathy or don’t care. Indeed most people can see problems, and often complain about them. But why does that not lead to action?