New DNA tracking helps spot rare ‘Tai O fish’ in Hong Kong waters after 10 years

DNA of rare Chinese bahaba found in Hong Kong waters last September, a month after about 1,300 hatchery-reared juveniles released into Pearl River Estuary

A Hong Kong academic has used environmental DNA technology to detect the critically endangered Chinese bahaba – commonly known as the “Tai O fish” – in local waters for the first time in more than a decade.

Jack Ip Chi-ho, an assistant professor at Lingnan University’s division of science, co-led the study with Wang Junjie, a professor at South China Normal University in mainland China. Together, they developed a genetic identification method capable of detecting traces of Chinese bahaba DNA left in the marine environment.

The rare species’ DNA was identified in Hong Kong’s western waters in September last year, one month after about 1,300 hatchery-reared juvenile Chinese bahaba were released into the Pearl River Estuary from the mainland.

Lingnan University said the finding – the first in over 10 years – suggested some of the released fish may have entered Hong Kong waters.

“The new detection technology developed by our research team is highly sensitive, and if a fish has passed through an area and left behind even a tiny amount of eDNA, its presence can be accurately determined,” Ip said.

Environmental DNA, or eDNA, refers to genetic material shed by organisms into their surroundings, including cells, tissues, fluids and waste.