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Conservation

More action urged on potentially invasive alien wildlife in Hong Kong

Few new measures implemented since city ushered in biodiversity plan two years ago as lack of research and inventory persists

PUBLISHED : Saturday, 24 March, 2018, 6:00pm
UPDATED : Friday, 04 May, 2018, 9:54am

Hong Kong must do more to prevent potentially invasive alien species from becoming established in the city, including tightening or introducing laws on animal imports and clamping down on “mercy releases” into the wild, experts say.

Despite identifying such wildlife as a key threat and challenge in its Biodiversity Strategic and Action Plan (BSAP) two years ago, few new measures have been implemented by the government to control the situation.

The lack of both research in the area and an inventory means authorities still lack understanding about the impact of most invasive species.

The concerns come amid more anecdotal evidence that the potentially invasive Sabah giant grouper, a carnivorous and hardy hybrid created in a lab and farmed for food is now breeding in Hong Kong waters. Juveniles are being caught in the harbour.

Environmentalists believe this could spell disaster for the local marine ecosystem.

“My feeling is that they didn’t really do much in the BSAP to address the issue of invasive species,” said Dr Michael Lau Wai-neng, director for wetlands conservation at WWF-Hong Kong. Lau served on the steering committee tasked with advising the government on the plan’s formulation from 2013 to 2016.

Fears of ecosystem imbalance raised over hybrid Sabah giant grouper in Hong Kong waters

Recommendations to introduce more legislation to regulate certain potentially invasive wildlife imported into Hong Kong for food or the pet trade, were turned down by the Agriculture, Fisheries and Conservation Department in favour of doing more on public education, Lau said.

“But I don’t really see how effective this has been.”

A department spokesman said the government was still at work on an inventory and would be conducting a preliminary risk assessment to better understand their impact on the local ecology. Alien species are those introduced outside their natural distribution.

“The government encourages universities and non-governmental organisations to conduct research studies on invasive alien species through funding support,” he said.

“The knowledge acquired from such studies and the results of risk assessment will inform managing them in Hong Kong.”

A failure to tackle the invasion and spread of some species has already had irreversible effects on Hong Kong’s ecology. About one-third of the 3,000 species of plant in Hong Kong are alien.

Aggressive plants such as the fast-growing mikania micrantha vine, or “mile-a-minute weed”, have been spreading across Hong Kong for years, forming thick canopies over natural vegetation and preventing photosynthesis.

In low-lying wetlands and rivers, mosquitofish – initially imported to eat mosquito larvae – and the tilapia fish – are classified by the International Union for Conservation of Nature as one of the world’s worst alien invasive species. Lau said they have been replacing native species such as the ricefish in streams.

Prevention is the most effective strategy
Dr Michael Lau, WWF-Hong Kong

“In some places, biodiversity is actually declining,” he added.

The government currently controls the spread of certain invasive plants and insects through targeted removals. But Lau said this was not cost-effective or a good use of public resources. “Prevention is the most effective strategy.”

Without predators or competitors found in their original habitats, alien species can hamper the survival of native species and the proper functioning of ecosystems. They can also pose public health concerns for humans.

As an international trading hub, Hong Kong has seen some species introduced accidentally, such as the imported red fire ant. Others imported for food, such as the American bullfrog and Sabah giant grouper or pets such as red-eared slider turtles, end up in the wild due to deliberate releases, often as part of religious rituals.

Unless released in a protected area, the activity is largely unregulated.

“In many parts of the world, you would not be allowed to release any non-native species anywhere in the wild,” said Dr Howard Wong Kai-hay of City University and a former chief government veterinarian.

“It is a major concern for local species as we don’t know how well the local ecosystem can tolerate them.”

Last month, the Eco- Education and Resources Centre, an environmental NGO, said it had been receiving reports from fishermen of juvenile-sized Sabah giant groupers being caught in the harbour.

It was not known whether the fish were escapees from fish farms or deliberately released, but in 2016, scientists discovered that the fish could spawn in captivity.

“If they are sterile it is OK, but if a new species is fertile, there is a much larger concern,” Wong said, noting that without controls “entire populations of fish species” could be decimated.

The best solution, he said, was to step up public education and draw up proper guidelines on what species were more sustainable for release. Wong is currently working on devising such guidelines.

A spokesman for the Kadoorie Farm and Botanic Garden’s ecological advisory programme said it was difficult to regulate the issue of the Sabah giant grouper as it was imported as a food product.

“There’s no way you can comprehensively control imports through sea or air. It would require a lot of manpower and resources.”

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Rather than singling out religious groups, he suggested tackling the problem from an animal welfare perspective. “They should be able to understand that there is more than one way to express compassion,” he said.

Any activity that leads to the suffering of an animal violates animal cruelty laws, punishable by a maximum fine of HK$200,000 (US$25,500) and three years in prison upon conviction.

The department spokesman said it would keep in view the need to tighten or introduce stricter import control of potentially invasive alien species and keep discouraging the public from taking part in mercy releases.