Yuen-Wa Ho (Derek)
Researcher, Cetacea Research Institute
Ph.D. Candidate, The University of Hong Kong (2015 - present)
B.Sc. (Ecology and Biodiversity), The University of Hong Kong (2013)
Supervisor: Dr. Leszek. Karczmarski, The University of Hong Kong
Co-Supervisor: Dr. David. M. Baker, The University of Hong Kong
Dr. Tzu-Hao Lin, Academia Sinica, Taiwan
Dr. Tomonari Akamatsu, Fisheries Research Agency, Japan
2017/2019: Diurnal pattern of habitat use vs. anthropogenic noise in core areas of Chinese white dolphins (Sousa chinensis) and finless porpoises (Neophocaena phocaenoides) in Hong Kong waters. (with T-H. Lin, T. Akamatsu and L. Karczmarski) - Ocean Park Conservation Foundation, Hong Kong
Conferences and Workshops
Ho Y-W., Lin T-H., Akamatsu T., Karczmarski L. (2018). Unsupervised classification of marine
soundscape with non-negative matrix factorization. Workshop on Big Data Challenges for Predictive Modeling of Complex Systems, Hong Kong S.A.R., China
Ho Y-W., Lin T-H., Akamatsu T., Karczmarski L. (2018). Spatial variation of marine soundscape within the habitat of Indo-Pacific humpback dolphins (Sousa chinensis) in Hong Kong. 2nd Ocean-Noise Asia Conference, Hakodate, Japan
Ho Y-W., Baker D.M., Wu Y., Lin W., Karczmarski L. (2017). Ontogenetic Dietary Shifts in the Indo-Pacific humpback dolphin (Sousa chinensis). 22nd Biennial Conference on the Biology of Marine Mammals, Halifax, Nova Scotia, Canada
Ho Y-W., Chan S.C.Y., Karczmarski L. (2015). Skin disorders and traumatic mutilations of Indo-
Pacific humpback dolphins (Sousa chinensis) in Hong Kong. 21st Biennial Conference on the Biology of Marine Mammals, San Francisco, U.S.A.
Ho Y-W., Scott S.Y.S. (2015). Chinese white dolphins research in Hong Kong and the Pearl River Region. Key speaker at World Wide Fund for Nature Hong Kong.
Organizing Committees (member)
2nd Regional Training Workshop in Computational Behavioural Ecology: Spatial Ecology and Quantitative Analyses of Animal
1st Regional Training Workshop in Computational Behavioural Ecology: Quantitative Ecology and Population Modelling using NOVA Computational Platform
Publications and Reports
Karczmarski L., Huang S-L., Or C.K.M., Gui D., Chan S.C.Y., Lin W., Porter L., Wong S.W.H.,
Zheng R., Ho Y-W., Chui S.Y.S., Tiongson A.J., Mo Y., Chang W-L., Kwok J.H.W., Tang R.W.K., Lee A.T.L., Yiu S-W., Keith M., Gailey G. & Wu Y. (2016). Humpback Dolphins in Hong Kong and the Pearl River Delta: Status, threats, and conservation challenges. Advances in Marine Biology.
Karczmarski L., Huang S-L., Porter L., Wong S.W.H., Or C.K.M., Chan S.C.Y., Ho Y-W., Chui
S.Y.S., Lin W., Zheng R., Gailey G., Tiongson A.J.C. & Wu Y. (2014). The Indo-Pacific
humpback dolphin (Sousa chinensis): Hong Kong Red List Assessment. WWF and Hong Kong Red List Authority, Hong Kong.
Research Assistant, Cetacean Ecology Lab, School of Biological Sciences, The University of Hong Kong - (2013 - 2015)
Volunteer Research Assistant – Komodo Survival Program
Assisted with population survey of Komodo dragons (Varanus komodoensis) and sustainable education and development, in Wae Wuul Reserve, on the island of Flores, southeast Indonesia (July 2012)
© Derek Ho
© Derek Ho
© Derek Ho
© Derek Ho
The deposition in growth layer groups (GLGs) in dolphin teeth provides a temporal archive of the nitrogenous input, which can be valuable in studies of their foraging ecology and environmental conditions. In terms of foraging ecology, the weaning age (a stage of transition from milk to solid prey consumption) can be reflected by trophic level shift across life stages. The weaning age of Indo-Pacific humpback dolphins (Sousa chinensis), locally in Hong Kong and China known as Chinese white dolphins, remains poorly known, although a recent photo-ID study off Taiwan indicates that mother-calf social separation occurs after 3-4 years. On the other hand, as delphinids occupy higher trophic levels, tracing back any shift in δ15N may provide indications of anthropogenic impacts. We hypothesize that N-enriched sewage source that enters coastal environments is sufficiently variable so that δ15N in dolphin teeth may indicate the N provenance. In my postgraduate study, I apply stable isotope analysis to investigate (i) the ontogenetic shifts in the diet of Chinese white dolphins, (ii) determine their weaning age and (iii) document the trend in N-pollution in the Pearl River Estuary (PRE). This study will provide insights into individual dietary life history that cannot be obtained through traditional field observations of free-ranging dolphins, and, with further analyses of dolphin teeth from several locations across the PRE, it will use these long-lived marine mammals as bio-indicators of the region’s environmental history.
Another part of my postgraduate research involves acoustic environment of humpback dolphins in Hong Kong waters. I focus primarily on soundscape, the collection of environmental sound, biological sound, and anthropogenic noise, which represents the important sensory signal for the habitat selection of any cetacean. Long-term noise can alter the soundscape, and disrupt the acoustic communication of soniferous organisms. The Pearl River Estuary is among the world's most developed coastal regions, with massive coastal developments and construction projects that span across the entire estuary, which generate intense underwater noise. The resulting impacts on marine mammals inhabiting this shallow-water coastal habitat are likely vast and unceasing, yet very little of it has been adequately investigated. In this project, as part of my Lab’s ongoing long-term field research surveys, I map the soundscape of Hong Kong waters and, with the use of long-term recording stations, I collect large volume of underwater recordings. Through this intensive year-round research effort, I will investigate the habitat use and acoustic behaviour of various marine animals inhabiting Hong Kong waters, including soniferous fishes and invertebrates, and of course the two coastal cetacean species that are found in Hong Kong year round, the Indo-Pacific humpback dolphin and Indo-Pacific finless porpoise (Neophocaena phocaenoides). This part of my postgraduate research will apply also machine learning techniques to separate biological and non-biological sound from noisy field recordings, which can provide more information on prey availability, biodiversity, habitat quality, and human activities.
This somewhat unconventional combination of biochemical techniques with bioacoustics represents an exciting new avenue of multifaceted and cross-disciplinary approach to studies of marine mammals, and complements very well my Lab’s ongoing, long-term research in behavioural-, population- and conservation ecology.
Biochemical and Bioacoustic study of Indo-Pacific Humpback Dolphins: Ontogenetic shifts, soundscape, and environmental history of the Pearl River Delta
Scholarships and Awards
2018: Best Student Oral Presentation - 2nd Ocean-Noise Asia Conference, Hakodate, Japan
2017: Student Conference Travel Grant Award - Society for Marine Mammalogy
2015: Student Conference Travel Grant Award - Society for Marine Mammalogy
2015-2019: Postgraduate Scholarship - The University of Hong Kong