Higher Trophic Predatory Fish Research

Higher trophic predatory fish are often found in deeper waters, offshore from shallow reefs. Aggregations of these predatory fish are common around deep isolated pinnacles, where predation, cleaning, and mate acquisition are often most successful. The resulting biodiversity and sheer abundance of marine life that therefore exists around these pinnacles, naturally creates diving 'hotspots'.

Occupying a higher position in the food web, the predatory roles of these fish are essential for maintaining biodiversity amongst communities of organisms lower down the web, allowing co-existence of competing organisms. Predation is also key to ensure that no single species dominates the reef by outcompeting other species, which would have significant knock-on effects to overall biodiversity and ecosystem resilience.

Global Reef has established a long term monitoring program, identifying population trends amongst a number of data deficient predatory species. This information may be of significant importance in defining sustainable fishing practices. During COVID 19, Koh Tao saw a rapid and significant decline in the volume and frequency of divers visiting offshore isolated pinnacles – the first time anything of this nature had occurred since dive tourism began to thrive, more than 20 years ago.

Global Reef has combined data collected pre-, during-, and post pandemic, which has provided a unique insight into the relative impact that various different resource users and stakeholders may have on isolated pinnacles and higher trophic predatory fish. Findings from such a rare and unique research opportunity may be of significant importance when making policy changes in relation to resources users.


Artificial Reef & Wreck Research

Wrecks and other types of artificial reefs create habitable spaces for marine organisms, as well as offering a place for coral settlement and attachment. As life begins to inhabit and aggregate around artificial reefs, this attracts divers - often relieving pressure on nearby natural reefs.

As natural reefs become increasingly threatened by global stressors, artificial reefs may play a key role in providing refuge sites for a diverse range of reef-associated organisms, spanning the entire food-web. Wrecks are common aggregation sites for predatory fish species, many of which are commercially valuable. The habitats that wrecks and artificial reefs provide to marine life could be of significant importance, as the world continues to tackle the global issues threatening natural reefs.

Global Reef is working to identify the relative importance and impact of artificial reefs located close to natural reefs, as well as modelling what makes them successful. This research could be of significant value in the design and development of future artificial reefs that aim to provide habitats or refuge sites to threatened marine organisms.

The research team are currently writing a research paper on comparing fish assemblages on artificial reefs, as an assessment of their performance as a fisheries management tool in the Gulf of Thailand.


Crown of Thorns Population Studies

During their adult life stage, Crown of Thorns Starfish (Acanthaster planci) feed on the live polyps of corals. Providing there is a healthy population of Crown of Thorns (COTs) on the reef, they play an important role in maintaining diversity amongst different types of hard corals, ultimately having a significant effect on the entire reef's biodiversity. Through predation of hard coral colonies, space subsequently becomes available for settlement of coral larvae, hence promoting genetic diversity amongst corals, and ultimately increasing reef resilience.

When population densities exceed a certain threshold, these corallivores (coral eating predators) impose a significant threat to coral reefs. This has often been associated with overfishing and high nutrient loads in the water. COTs 'outbreaks' of significantly high population densities often lead to mass mortality of corals through predation, resulting in large scale reef degradation and habitat loss for other marine organisms.

Global Reef works to further define the specific local population densities in which COTs may pose a significant threat to the reefs of Koh Tao. Research has been aimed at quantifying the relative impact of varied densities on reef health, as well as identifying areas where Crown of Thorns populations are highest around the island.

The research team are currently writing a research paper which includes a preliminary assessment of the effects of COT outbreaks in the Gulf of Thailand, as a means of improving the management of outbreaks in the region.


Monitoring of Marine Functional Groups

Each organism within any ecosystem has a specific ecological niche (role, job or function) which they occupy. As multiple niches are occupied by a diverse range of organisms, this ensures the entire ecosystem remains balanced and healthy.

By identifying the roles of marine organisms living on the reef, organisms with similar roles can be grouped together, forming 'functional groups' (e.g. herbivores, detritivores, mid-trophic predators, apex predators etc.).

Global Reef has established ongoing monitoring programs for reef-associated functional groups. This allows identification of relative changes to these groups, as well as the potential effects these changes have had on other elements of the reef-ecosystem. In doing so, Global Reef is modeling the interactions between functional groups, assessing the relative impacts of different functional groups on reef health, and identifying key changes that may pose threats to local reefs.


Coral Restoration

Coral reefs occupy less than 0.1% of the ocean, yet provide habitats to over a quarter of all marine organisms. Corals are one of the most important organisms in supporting the high level of biodiversity found on reefs. Hard corals play an unparalleled role in providing habitats to a number of reef associated organisms, and in doing so, structure entire ecosystems.

Global Reef is actively involved in the restoration of coral reefs around Koh Tao. Artificial reefs constructed using concrete, metal or limestone may be deployed in areas that lack stable reef substrates. These artificial structures provide a stable substrate for corals to be transplanted onto, allowing them to develop into new colonies.

Working in collaboration with the Thai Department of Marine & Coastal Resources, these projects contribute to the large scale, island-wide restoration and protection of Koh Tao's reef ecosystems.


Digital 3D Modelling of Coral Reefs

Through the application of advanced photogrammetry methods, Global Reef are producing 3D models of coral reefs, reef structures, and artificial reefs.


By creating these 3D models on arecurring basis, historical records are created, allowing for long term research and monitoring of coral reefs. Future research questions will have the ability to incorporate historical data from coral reefs, allowing trends, processes and developments to be identified by travelling ‘back in time’. This is critical for developing our knowledge and understanding of threats subject to reef ecosystems, and will allow early intervention and conservation efforts to be delivered in the future.


Global Reef offer digital 3D models, supported by empirical data gathered in situ, to scientists and institutions across the world. This has created the possibility for individuals to apply their research questions to coral reefs, without the need to visit them. This therefore significantly contributes to the overall Global Reef mission: ‘To connect a global audience with the marine world… anywhere and everywhere’!