Researchers used environmental DNA to detect the critically endangered Chinese bahaba in Hong Kong waters for the first time in more than a decade. A Lingnan University press release dated July 23, 2026, said the team found traces of the fish at four sites during their 2025 water survey.
Sometimes the biggest news can come from the smallest clues. According to a Lingnan University press release dated July 23, 2026, researchers found traces of the Chinese bahaba in western Hong Kong waters. The release calls it the first scientific discovery of this fish in the city in over a decade. The fish itself was not caught. The evidence came from DNA left behind in seawater.
About the Chinese bahaba
The Chinese bahaba is a large fish found off the Chinese coast. It can grow up to two meters in length and is often called the "Panda of the Sea". In the 20th century, it was abundant around Tai O in Hong Kong, where local people called it the "Tai O fish." The species is classified as critically endangered by the International Union for Conservation of Nature and as a first-class protected wild animal in China. The Lingnan release said the fish's swim bladder has value as medicine. That demand led to intense overfishing and a dramatic population decline in the wild.
How scientists track fish they can't see
Fish release DNA in tiny bits of mucus and waste as they swim. Scientists call this environmental DNA, or eDNA. Lingnan University's Division of Science jointly developed an eDNA test for the Chinese bahaba using mitochondrial genome sequences. The test can identify the species without confusing it with other fish, and the release said lab tests and computer analysis confirmed this. The work was led by Prof. Jack Ip Chi-ho of Lingnan University and Prof. Junjie Wang of South China Normal University. The study was supported by the Marine Ecology Enhancement Fund of the Airport Authority Hong Kong and two other research projects.
What the survey found
Between January and September 2025, the team surveyed 23 sites in western Hong Kong waters. They took three one-liter samples of seawater at each site, and because the team returned to the sites several times, the sampling added up to a total of 414 samples. Sterile distilled water was also used as a control to rule out contamination. DNA of the Chinese bahaba was detected at four sites in September 2025: Tai O, Sha Chau and Lung Kwu Chau Marine Park, Southwest Lantau Marine Park and Sunny Bay. Tai O had the highest frequency and concentration. That timing coincides with an August 2025 release of about 1,300 hatchery-reared juvenile bahaba into the Pearl River Estuary. The researchers suggest some of these young fish may have entered western Hong Kong waters.
Why this approach matters
Ip explained that the fish is so rare that it is very unlikely to be encountered in regular surveys. Such surveys usually involve trawling or capture, and require skilled staff and a lot of money. They can also harm seabed habitats and put non-target species at risk. Water sampling is a less invasive method because researchers can verify a species' presence without having to catch or disturb it. The team says the tool could help groups evaluate the effectiveness of juvenile release programs. It could also help biodiversity monitoring in the Guangdong-Hong Kong-Macao Greater Bay Area.
What this does and does not tell us
The method can help with long-term monitoring of the bahaba in the Pearl River Estuary and adjacent waters, the team says. A trace of DNA tells you a fish has been there, but not how many. Because the detections coincide with the hatchery release, the findings do not show that a wild population has survived; the DNA may well have come from released juveniles. Prof. Ip said the bahaba has not been recorded in Hong Kong waters for over a decade. With this tool, conservation groups can track the movement of released fish without having to catch them.