Cheyenne Alexandria Phillips

Supervisor: Dr. Darren Yeo Chong Jinn

Project: Investigating fish and macroinvertebrate diversity of macrophyte communities in reservoirs around Singapore

In 2006, PUB launched the Active, Beautiful and Clean (ABC) Waters programme where macrophytes (aquatic plants) were introduced to improve water quality, aesthetics and biodiversity of Singapore’s freshwater bodies. However, the relationships between these macrophytes, fish and macroinvertebrates have not received much scientific attention. Community interactions within spontaneous macrophyte assemblages have also been neglected. Therefore, this study aims to describe and compare fish and macroinvertebrate diversity of selected spontaneous and constructed macrophyte communities. Macrophytes, fishes and macroinvertebrates will be sampled via quadrat sampling, trapping and netting. This study has potential in applied research questions (e.g. impacts of the surrounding land use on the macrophyte-associated communities; the usefulness of man-made structures and habitats in supporting/enhancing such communities; controlling of mosquito breeding).

Kenny Chua Wei Jie

Supervisor: Dr. Darren Yeo Chong Jinn

Project: Impacts of introduced fishes at stream-reservoir interfaces in the Central Catchment Nature Reserve

The Central Catchment Nature Reserve contains natural forest streams which are rich in native aquatic species. However, these streams are in close proximity and connected to artificial reservoirs, which are known to harbour established introduced fish species such as the marbled goby (Oxyeleotris marmorata). These introduced fishes could pose an ecological risk to valuable native species and locally rare natural freshwater habitats. As such, my project aims to describe the aquatic community at stream-reservoir interfaces, determine impacts of selected introduced fish species at the community level and predict the potential spread of said species.

Ng Di Sheng Dickson

Supervisors: Dr. Darren Yeo Chong Jinn & Dr. Rudolf Meier (EvoLab)

Project: A preliminary study of aquatic leeches in Singapore

Aquatic leeches are important ectoparasites and predators in aquatic systems throughout the world. In Singapore, they are found in both natural as well as artificial aquatic habitats. However, they are very poorly studied in Singapore; besides a lack of understanding of their ecological role in our freshwater ecosystem, we do not even know exactly how many and what species exist in our water bodies. The first part of my project involves discovering and documenting the leech fauna in Singapore. I will be going to the different water bodies in Singapore to search for leeches, and finding out their identities and taxonomic placement using morphological and molecular approaches. The final aim is to publish a species list and identification key for the aquatic leeches of Singapore. The second part of my project involves analyzing the diet of the Asian buffalo leech, which are found in Singapore’s forest streams, using Next Generation Sequencing techniques. This should allow us to better understand their function in our ecosystem for better appreciation of these slimy critters. This also serves as a proof of concept for biodiversity research using metabarcoding for diet analysis.

Khaizar Khuzema Shakir

Supervisor: Dr. Darren Yeo Chong Jinn

Project: Habitat characteristics, survival and growth of native crab and non-native crayfish in Sime track drainage

Many species of freshwater crayfish have been recorded to be biological invaders. Presently, the two most popular non-native crayfish species in local aquarium trade are the Australasian red-claw crayfish (Cherax quadricarinatus) and the North American red swamp crayfish (Procambarus clarkii). Of the two, C. quadricarinatus is established in a number of Singapore’s reservoirs while P. clarkii has been observed in a single reservoir. Some of these reservoirs are surrounded by forested catchments which serve as refugia for native freshwater decapod crustacean species such as the lowland freshwater crab (Parathelphusa maculata). The crayfish could negatively affect the native freshwater crab fauna through resource competition – for example, the Sime track drainage which contains syntopic population of C. quadricarinatus and P. maculata. I will be investigating the habitat characteristics, survivability and growth of these described species in forested catchment conditions. Findings from this study could assess the invasion risk of C. quadricarinatus and P. clarkii, along with the vulnerability of P. maculata to biological invasions; thereby aiding management decisions regarding conservation of our native freshwater biota.

Song Yiluan

Supervisors: Dr. Hugh Tan Tiang Wah & Dr. Darren Yeo Chong Jinn

Project: Effects of macrophytes on cyanobacteria in Singapore’s reservoirs

Harmful cyanobacterial blooms pose a significant threat to the water safety of Singapore. Aquatic macrophytes have been shown to stabilize macrophyte-dominated clear water states and are considered to be a measure to control undesired algal growth in aquatic ecosystems. The objectives of my study are to 1) quantify the ability of several macrophyte species to inhibit the growth of phytoplankton, particularly cyanobacteria, to increase water clarity in Singapore’s reservoirs, 2) identify macrophyte densities at which they can effectively promote clear water conditions, and 3) recommend a set of macrophyte species and corresponding densities for further in-situ tests.

Tan Li Ying Claudia

Supervisor: Dr. Darren Yeo Chong Jinn

Project: Potential Interactions between a native and alien freshwater shrimp (Macrobrachium spp.) in Lorong Banir stream

Generally restricted to the open and artificial freshwater habitats in Singapore, the introduced shrimp Macrobrachium nipponense has been increasingly sighted along the outskirts of Nee Soon Swamp Forest, a refuge for many native freshwater species. This expansion of the alien shrimp’s range into forest streams could increase alien-native interactions. However, it is not known if M. nipponense could survive and grow as well/better than its native, forest-dwelling congeners. It is also not known if the alien shrimp could compete with native shrimp species in zones of habitat overlap. This study thus aims to assess the interactions of M. nipponense with Macrobrachium malayanum, a similarly-sized and abundant native forest shrimp which would most likely encounter the alien shrimp in Singapore’s forest streams. I will be investigating the 1) interspecific habitat overlap by associating the stream’s abiotic parameters with each species’ abundance; 2) competitive dominance of either shrimp species over the other with and without a limited resource, through an ex-situ behavioural study and; 3) the combined effects of abiotic factors and interspecific biotic interactions on the survival and/or growth of both species. It is hoped that findings of this study could shed light on the invasive threat of M. nipponense and the vulnerability of M. malayanum to biological invasions in Singapore.

Loh Jun Yi

Supervisors: Dr. Sandric Leong and Dr. Darren Yeo Chong Jinn

Project: A physiological study on the effects of varying light intensities on red tide species, Prorocentrum micans

Harmful algal blooms (HABs) threaten aquatic ecosystems worldwide. In recent years, the frequency of HABs have been increasing. This trend is often attributed to direct and indirect anthropogenic stressors which create environmental conditions suitable for harmful algal species to bloom. Considering our proximity and reliance on aquatic environments for resources and industry, HABs is an issue that has to be tackled. Prorocentrum micans is a dinoflagellate which causes HABs in the form of red tides. This project aims to ascertain the physiological responses of the tropical strain of P. micans when exposed to varying light intensities. Specifically, this study will look into the change in growth rates and pigment profiles of P. micans as it responds to new abiotic conditions. Knowledge regarding the physiology of harmful algal species is crucial to the development of HAB management strategies, be it in the prediction, mitigation or the prevention of blooms.

Claire Keung Ka Yee

Supervisors: Dr. Tan Heok Hui and Dr. Darren Yeo Chong Jinn

Project: Autecology of the non-native peacock basses (Teleostei: Cichlidae: Cichla orinocensis, C. temensis) in selected Singapore reservoirs

The peacock basses (Cichla orinocensis and Cichla temensis) are piscivorous fishes native to South America’s Orinoco and Amazon River basins that have been introduced through the ornamental pet trade or as game fish. In Singapore, the peacock basses have formed established populations in 7 of the 17 reservoirs such as Bedok, Pandan and Upper Peirce Reservoirs but are unfortunately not well studied. Being aggressive piscivores, these fish are more likely to be successful invaders and alter fish assemblages. Hence, my project aims to assess the current status of the peacock basses in these freshwater habitats by studying their autecology. I will also conduct stable isotope analysis to study nutrient allocation in multiple tissues.

Rachel Low Rui Ci

Supervisors: Dr. Tan Heok Hui and Dr. Darren Yeo Chong Jinn

Project: A preliminary study of marine ornamental fish trade in Singapore

The marine aquarium trade is rapidly expanding and there is a growing demand for tropical marine aquarium fishes in the international market, e.g., interest in coral reef systems has led to an increased demand for coral reef fishes. In Singapore, freshwater fishes are the primary revenue for the aquarium trade, with species diversity (along with likely origins/import sources) being well documented. However, such information is lacking for marine ornamental fish imported into Singapore; although a preliminary listing is available for aquacultural species. I aim to consolidate a species list and document trends from collected data. With the fish trade being a known pathway of biological invasion, ornamental fishes released intentionally or unintentionally into our marine environments could pose a threat to native species. In light of the potential threat to vulnerable marine systems in Singapore, I also aim to evaluate the nature and volume of non-native marine fishes imported, as well as to determine the sustainability of this trade.