Hong Kong customs officials have made their largest shark fin seizure ever, uncovering 26 tonnes taken from 38,500 endangered sharks inside a pair of shipping containers from South America, it was revealed on Wednesday.

The two consignments, worth HK$8.6 million (US$1.1 million), more than doubled the 12 tonnes of shark fin seized in all of 2019, according to assistant superintendent Danny Cheung Kwok-yin of the Customs and Excise Department’s marine enforcement group.

“Each consignment consisting of 13 tonnes broke the previous record seizure of 3.8 tonnes of controlled shark fins made in 2019,” he said.

Cheung said both consignments were sent from the same shipper to the same Hong Kong logistics company. Customs officers have arrested the owner of the logistics firm, but the 57-year-old man has been granted bail pending further investigation.

A law enforcement source said the value of the seizure would have been much higher if it had been the highest-grade shark fin, which can cost thousands of dollars per kilogram.

The two containers arrived from Ecuador within 10 days of each other in January, but the huge haul was only discovered when customs officers opened the containers at their Kwai Chung cargo examination compound on April 28 and May 4.

Officers said their suspicion had been aroused because the containers had Spanish-language markings identifying them as dried fish.

“It’s unusual for some imported goods to be described in foreign languages other than English,” Cheung explained, adding that customs officers had seized shark fins shipped from Ecuador before.

Each container contained more than 300 nylon bags of dried shark fins, with about 90 per cent of the goods from controlled species.

Seized fins largely came from thresher and silky sharks – both protected species, according to the customs department.

Endangered species protection officer Ken Chan Hon-ki of the Agriculture, Fisheries and Conservation Department estimated the fins had been removed from about 31,000 thresher sharks and 7,500 silky sharks.

Cheung believed at least some of the seizure was for local consumption and destined for Hong Kong eateries and shops, noting the investigation was continuing and further arrests were possible.

Apart from the two Ecuador consignments, customs officers this year had already confiscated 15 tonnes of shark fins worth HK$5.4 million and made two arrests.

For the whole of 2019, 12 tonnes of banned shark fins worth HK$8.9 million were seized, with 13 people arrested. That marked a substantial jump from 2018, when customs officers seized 641kg of shark fins worth HK$510,000 and made five arrests.

The assistant superintendent said the rise in seizures this year was the result of enhanced inspections and intelligence exchanges with the mainland and other countries.

He said the customs department would continue to liaison closely and cooperate with outside law enforcement agencies to combat smuggling activities.

Under the Protection of Endangered Species of Animals and Plants Ordinance, importing, exporting or possessing endangered species without a licence carries a maximum penalty of 10 years in jail and a HK$10 million fine.

Gloria Lai Pui-yin, senior conservation officer for sustainability with animal rights group WWF-Hong Kong, said the scale of the seizure “definitely came as a surprise to us”, noting that, between 2014 and 2018, 30 seizures were made but the total only amounted to about six tonnes.

“But this does not mean demand is rising again. It could be that traders are seeing a chance to ship the shark fins while government officials in other countries are preoccupied with efforts to combat the Covid-19 pandemic,” she said.

Lai said that, with people generally dining out less because of the pandemic, a local increase in demand for shark fin was unlikely. However, a WWF survey of 859 people still found seven out of 10 Hongkongers had eaten shark fin in 2018, mainly at three kinds of occasion: weddings, office functions and family gatherings.

“WWF-Hong Kong therefore urges hotels and restaurants to stop selling shark fins and for companies to make a ‘no shark fin’ pledge,” Lai said.