Current Research Interests
1. Quantifying Effects of Human Pressure
Chronic stressors resulting from of urbanization, industrialization, agriculture, biological invasion, and destructive fishing practices have caused detrimental effects in marine habitats all over the world. The loss of keystone species can trigger cascading effects by shifting community assemblages and trophic structures in impacted reefs. For example, overfishing of wrasses and triggerfish can lead to an outbreak of sea urchin populations, turning the habitat into a prey- and herbivore-dominated ecosystem.
However, there is currently no consensus how reshuffling of species composition can affect ecosystem functionality. My research quantified the pressure exerted by worsening water quality and its effects toward biodiversity and ecosystem function provision. It demonstrates that whilst new ecological equilibrium often means bad news for fisheries production, highly impacted sites show remarkable resilience in maintaining secondary functions, such as herbivory and predation strength.
As human pressure continues to exert stress toward important habitats globally, more research is needed in to understand how ecosystems will respond to pressure and how we can adapt to these changes.
Smog and pollution enshroud Hong Kong, a coastal megacity
2. Protecting Vulnerable Habitats with MPA
Marine Protected Areas (MPA) are important conservation instruments used to protect marine biodiversity and natural resources. MPAs safeguard vulnerable marine habitats by limiting anthropogenic pressures and promoting spillover effects that could enrich neighboring waters. Well-designed MPAs can sustain populations of overexploited fish species and rebuild fish stock.
Despite the potential to provide long-term benefits to fisheries and biodiversity, MPAs often face challenges that prevent them from performing optimally. For example, standalone MPAs are usually small, which are ineffective in connecting important habitats, such as feeding and breeding grounds. In remote areas, MPAs often lack funding and manpower, which could hamper the enforcement of set rules. Coastal communities can also resist policy implementation if it diminishes the short-term productivity of unregulated fisheries.
I’m currently working on long-term monitoring projects in Nusa Penida MPA, Tanjung Bira, and Dampier Strait MPA (Raja Ampat Regency) to understand how habitat protection (or the lack of) and community engagement can affect the abundance and biomass of keystone fish species and megafauna. The resulting datasets have the potential to inform the public, government, and other stakeholders regarding the health of these highly biodiverse reefs.
Villagers in Raja Ampat commuting with a small canoe
3. Utilizing Citizen Science for Conservation
The participation of citizen scientists, or nonprofessional researchers and volunteers, is invaluable for collecting biodiversity data, increasing public engagement, and supporting underfunded research projects at remote locations. For example, public usage of the open-source platform iNaturalist is credited for the discovery of new species, invasive species, and species previously thought to be extinct.
I’m working on a couple of long-term data collection projects involving citizen scientists in three remote Indonesian coral reefs. First, I initiated the iNaturalist projects “Marine Biodiversity of Nusa Penida, Tanjung Bira, and Dampier Strait” to catalogue all uploaded pictures and identification of every marine life in respective locations. The goal is to create ID books that inform local communities, scuba divers, and other stakeholders of the surrounding biodiversity. Second, I contribute a large dataset of sea turtle cheek scales, manta ray belly spots, and mola (sunfish) body patterns to several research organizations. The purpose of identifying individual sea turtles, manta rays, and molas is to learn about population size, habitat use, sex ratio, net migration rate, and many more. This research is important to study rare charismatic megafauna in remote locations, where facilities and resources such as tags and data loggers are hard to come by.
A young hawksbill sea turtle displaying unique self-identifying scales on its cheek. Green box indicate the face area detected by AI. Source: Internet of Turtles
4. Bridging Technology and Marine Science
Traditional research techniques remain very popular methods to study the ecology of coral reefs, mangroves, and their inhabitants. However, environmental conditions such as fluctuating tidal cycles, harsh weather conditions, and remoteness of study sites often make in situ fieldwork very challenging. I am highly interested in exploring novel methods to make ecological studies easier and more replicable.
One of the studies I have completed is 3D scanning complex mangrove root structures in Hong Kong using photogrammetry. The models were then printed and used in a series of controlled experiments to understand predatory avoidance and hunting strategies of select mangrove fishes. This novel study allowed us to observe rare predation events occurring in rapidly decimated natural habitats.
Currently, I am working on several projects involving AI and machine learning. First, I am using photogrammetry to map reef manta ray cleaning stations in Nusa Penida to understand how structural complexity can indirectly promote megafauna abundance by supporting small cryptobenthic cleaner reef fishes. Second, I’m partnering with a computer vision team in Hong Kong University of Science and Technology to develop algorithms that can automatically detect and identify coral and fish species from pictures and videos, which can streamline biodiversity monitoring and surveys.
3D scanned mesh model of Kandelia obovata, a mangrove tree species used as nursery of juvenile reef fish
5. Restoring Habitats & Mitigating Invasive Species
Coral reefs, mangrove forests, and seagrass meadows are marine habitats that provide food, shelter, and protection for a significant number of marine organisms. However, worsening environmental conditions in the form of climate change, ocean acidification, overfishing, and introduction of invasive species have significantly impacted the health of these important habitats.
I’m currently working on several ongoing conservation projects to ameliorate the destruction of remote coral reefs. In Nusa Penida and Tanjung Bira, we are restoring damaged reefs by ‘planting’ fragments of fast-growing Acropora spp. using artificial hexagonal structures. When maintained properly, these structures are highly effective at returning lost ecosystem functions and services in damaged reefs. For example, within months, we are already seeing cryptobenthic crustaceans and small fishes returning and using the coral structures as habitat and food source!
Invasive species plays a big part in the shift of ecological balance and loss of functions. In the Caribbean, introduction of lionfish decimate populations of native fishes and threaten the livelihood of millions of local fishers. In Indo-Pacific, we are facing an invasion of a relatively unknown coral-killing sponge Chalinula nematifera. Our initial studies have found that these sponges grow about 1-4 mm per day on top of many species of hard corals and kill them in the process. More studies are underway to understand the sponge’s feeding and reproductive process in order to suppress its spread to other habitats.
Indo Ocean Project interns restoring damaged coral reef
Invasive Chalinula nematifera (bottom) killing a colony of native hard coral Galaxea fascicularis (top)