Jake Dytnerski

Ph.D. candidate

Research

Hong Kong has a seasonally dynamic marine environment. Summer sea surface temperatures can exceed 30°C whereas winter temperatures can drop below 15°C. This range in temperature allows for year-round coral communities, and abundant growth of macroalgae in the winter. For my PhD, I am researching the role of the long-spined sea urchin, Diadema setosum, in the ecosystem, here in Hong Kong. Much work has been done on Diadema antillarum in the Caribbean, and some work has been done on the D. setosum as a bioeroder of coral reefs in the tropics. However, little is known about which marcoalgae these urchins feed on; how they affect the seasonal patterns of macroalgae growth and distribution; if the urchins target living corals here in Hong Kong or just the turf algae that grows on the dead skeletons of the corals. Answering these questions will help understand the food sources of the urchins and how their energy stores vary with the seasonal change in food abundance. I am also interested in the connectivity of the populations of D. setosum across its range, as they can be found from the East coast of Africa to French Polynesia, from Honshu, Japan to NSW, Australia. I want to compare the physiological performance of the urchins from stable tropical environments and highly variable environments to determine if they show extensive physiological plasticity, or if populations have adapted to variable environments. This will allow me to predict how these important grazers will cope with future conditions across their range.

Education

2016: Bachelor of Science, Honours Marine Biology, University of British Columbia, Canada

2013: Arts and Science Diploma: Biology, Langara College, Canada

Awards

2015: Dean of Science Scholarship – Biology research grant
2013: Betty and Tony Pletcher Memorial Scholarship – For Achievement in Biology
2012: Real Estate Foundation Biology Student Bursary – Bursary for Biology students

Biodiversity and Oyster Reefs of Hong Kong

There is currently no ecological or biological base li ne for oyster habitats in Hong Kong. These habitats are globally recognised to be biologically diverse and highly productive. Despite the long history of exploitation of oyster habitats in Hong Kong, with written records pre dating the Qing Dynasty (c.1630s), there is no information on their current status or the diversity of species which rely on them.

Overall, this project will establish the first comprehensive dataset for fauna associated with these remnant oyster habitats and provide a base line from which to manage them into the future.

There is an urgent need to document baseline ecological conditions of oyster habitats while the natural ecosystem still exists from both scientific and socio-cultural perspectives, as well as to inform any potential future restorative conservation.

Project Objectives

1. Database of faunal biodiversity associated with oyster habitats and soft sediment shores including a reference collection of all key invertebrate species

New species record for Hong Kong, Nanosesarma pontianacense , found
inhabiting the pilot restoration reef at Lau Fau Shan.

2. DNA barcode for all the marine species and to create a DNA reference collection

3. Update the Hong Kong Register of Marine Species (HKRMS), founded by SWIMS and
funded by ECF and the HK node of the World Register of Marine Species (WoRMS)

4. Document the abundance and distribution of threatened or endangered species in habitat adjacent to oyster habitats

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