Silent sea

 [HK Wildlife Magazine]

The giant yellow croaker once supported Tai O’s fishing industry but now it stands on the verge of extinction.  

Locating giant yellow croakers (Bahaba taipingensis) as they spawn en masse in the Pearl River Estuary is a cinch if you know what to look out for, or more precisely, what to listen for.

As its name suggests, the fish  – also known as Chinese Bahaba and Tai O fish, and is the largest Sciaenid (drum or croaker) in the South China Sea – communicates with one another using drumming sounds produced by vibrating its muscles against its swim bladder.

And the fishermen of Tai O are well-versed in this game of hide-and-seek. Every February and March from the 1930s to the 1970s, about 60 trawlers and gillnetters set sail from the idyllic village to areas like Fan Lau and Lintin Island where fishermen would glue their ears to the hull of their boats, trying to pick up their prey’s underwater chatter so they could close in on the fish swarms.

The giant yellow croaker, which once flourished along the south-eastern coast of China from the Yangtze Delta to the Pearl River Delta and served as the mainstay of many a fisherman in Tai O, has been persecuted to oblivion and listed as critically endangered (CR) on the IUCN Red List.

What puts the species, spanning up to two metres and weighing at least 100kg, in the crosshairs of fishermen is its enormous swim bladders. Commercially known as fish maw, this organ has been celebrated by the Chinese for its purported medicinal powers. It is said to heal stomach ailments, help women recover from pregnancies and promote longevity. The larger the bladder, the steeper the price.

According to studies, in the late 30s, local fishermen caught 50 tonnes of the fish, which weighs as heavy as two double decker buses, every year. Tai O-based former shrimp trawler Wong Yung-gan, who hauled four giant yellow croakers up by chance along with netfuls of crustaceans in the 50s, said 140 catties of the croaker, which yields a mere catty of maw, was worth as much money as 200 catties of shrimp.

“It was a big deal if a fisherman strikes it lucky and caught netfuls of the giant yellow croaker. He could use the earnings to buy a few apartments…or give his boat a major overhaul,” said Wong who is in his late 60s.

Yet the advent of mechanical engines and the impact of overfishing decimated the species population. Thirty years on, fishermen only returned with only one-fifth of the former annual harvest. Now, large individuals have become so rare that catches would make it onto newspaper headlines and give birth to rags-to-riches stories.

In 2008, a recreational fisherman drew citywide attention for catching an 85kg giant yellow croaker, which fetched HK$1 million, near Kap Shui Mun Bridge. In 2012, a mainland fisherman made HK$3.5 million from selling an allegedly dying 80kg individual in Fujian.

Professor Yvonne Sadovy, an eminent fisheries scientist at the University of Hong Kong, said as the species become scarcer and scarcer, the value went up. “Now they have become more of a commodity…In other words, they seem to be traded as investment items rather than something useful in medicine.”

She added that the skyrocketing value of the fish has also created “high incentive” to keep fishing it.

The consequences of the species near expatriation are little known since it was already hovering on the brink before experts had the chance to study its biology.

“When we understand all the interactions among species in an ecosystem, we find that they all play a role. But no one would know what the specific role of this species was,” she lamented.

Whether or not we can turn around the fate of this once thriving marine giant is a question. But Sadovy says what we can take away from its story is that Hong Kong needs to be more proactive in protecting our marine biodiversity.

“In Hong Kong, we don’t have any legislation for protecting marine fishes…. We’re very behind much of the rest of the world in treating our marine biodiversity,” she said.

The giant yellow croaker has been protected on the mainland under Grade II State Protection since 1988. Sadovy says if the mainland is taking it seriously, so should Hong Kong.

She also suggested protecting the area where the giant yellow croaker aggregates to spawn, or to impose a moratorium during its breeding season.

As Sadovy puts it, the giant yellow croaker is a “Hong Kong legacy”. The species is more than just a profit-making tool. It is a part of our history, culture and biodiversity. If we don’t want to lose another species in our lifetime, there is a lot of catching-up for Hong Kong to do.



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