Known affectionately as the “coral mom,” 2019 Pew marine fellow and marine biologist Dr. Apple Pui Yi Chui has made it her mission to restore Hong Kong’s coral communities. And she has succeeded—by returning baby corals grown in her lab to the sea, Chui and her team of researchers at the Chinese University of Hong Kong have become the first in the region to achieve a nearly 90% coral survival rate.
That’s no small feat in her part of the world. Corals in the Tolo Harbor and Channel in northeastern Hong Kong have been hit hard by the impacts of urban development and population growth from the 1980s, with pollution and deteriorating water quality resulting in a significant loss of coral coverage. Chui’s work aims not only to restore the region’s coral communities, but to better understand the conditions corals can withstand amid increasing local and global environmental stressors.
This interview with Chui has been edited for clarity and length.
Growing up, I always liked the ocean. My family and I used to go to the beaches every weekend, where we’d run, explore rocky shores, and snorkel. That foundation led me to my work on coral spawning in Hong Kong. It’s risky and challenging. And I just love it.
My lab focuses on three areas of research: coral population and community ecology; the impact of climate change on coral communities in “marginal” environments, where conditions, such as water clarity and temperature, are highly variable or near the thresholds for coral survival; and coral breeding techniques. We use a sexual propagation technique—which involves gathering the egg and sperm bundles from corals as they spawn and then allowing them to fertilize and develop into baby corals—and then we transplant those baby corals onto degraded reefs. The goal is that these corals will then reproduce and thrive.
We mix gametes, eggs, and sperm from all parent corals together to create as much diversity as possible during spawning; this helps increase the chances for baby corals to have the right gene combinations to help them survive in changing environments. We then culture them into larvae and nurture them for two years in our lab-based nursery before planting them in the sea. In 2019, we planted our two-year-old sexually propagated corals on a field-based platform in the ocean for a year, allowing them to adapt to water conditions before being fully transplanted. There, 88% of the corals were still alive after one year. After that, we attached the corals to natural, rocky surfaces—where 100% of the corals survived after one year.
Corals in Hong Kong are mostly affected by local stressors, such as coastal development, pollution, and overfishing. Our restoration test ground, Tolo Harbor and Channel, once supported over 30 coral species and had high coral coverage, but this coverage rapidly dropped to almost nothing in mid-1980s.
Shortly after that, the government initiated a 10-year action plan to clean up the harbor, but the corals weren’t recovering. This is where our work comes in: helping to restore the region’s marine ecosystems by breeding and transplanting local corals.
Compared with corals in some other places, Hong Kong corals may have already been well adapted to a stressful environment—they experience large fluctuations in temperature and salinity year-round. So Hong Kong’s coralshaveenormous potentialfor expanding ourunderstanding of the limitsfor coral adaptation. Is it possible, for instance, that Hong Kong’s corals might be able to survive future climate change? If by studying Hong Kong’s corals we find out that some corals survive difficult conditions better than others, perhaps we can then selectively breed those corals to endure in the future.
The Coral Academy is an outreach initiative based at the Chinese University of Hong Kong that aims to raise community awareness about, and inspire action on, coral conservation. Many people in Hong Kong have never heard about the corals that used to exist in Tolo Harbor and Channel, so they don’t know what we’ve lost. That’s why we’re not only committed to bringing these precious coral ecosystems back, but also to inspiring the next generation of environmental stewards.
With the support of the university, we’re extending that work through the development of a coral nursery and education hub, which we expect to launch next year. The hub will upscale our existing work by providing a sustainable source of genetically diverse coral juveniles for local restoration efforts while fostering community engagement and awareness of coral stewardship.
Conservation is not about a few people doing lots of work and research. It requires everyone to make a difference. We need to talk about reducing global climate threats, improving local conditions, cutting down pollution, and protecting the corals that we still have. Even small actions can have significant consequences for our marine ecosystems.
I am truly humbled to receive these awards; they represent a significant recognition and encouragement not just for me, but for my entire team! This recognition motivates us to strive for even greater achievements. It also provides us with global exposure and valuable networking opportunities, which I hope will eventually lead to funding that can help sustain our environmental education outreach efforts in Hong Kong.