Cannabis bud was found on a fishboat at Anping Port in southern Taiwan: Google Maps, Wikimedia Commons

A 53-year-old Taiwanese captain and three Indonesian crew members were arrested on Thursday morning after suspected cannabis buds worth more than NT$300 million (nearly US$10 million) were recovered from a secret chamber on a fishing vessel at Anping Harbour in southern Taiwan.

At 1am on Thursday, officers from the Investigation Bureau, Coast Guard Administration and police jointly raided a fishing vessel which was returning from international waters, China Times reported.

Inside the boat was a secret chamber, with 519 packs of suspected cannabis buds, weighing more than a quarter of a tonne – 264 kilograms.

The illegal plants had an estimated street value of NT$300-400 million (US$9.87 to $13.16 million). The seizure is the largest amount of cannabis buds reported for five years.

Amid a shortage of illegal drugs, smuggling drugs from Southeast Asia to Taiwan via fishing vessels in international waters has become a lucrative sideline, the China Daily News reported.

Preliminary investigation showed that the Taiwanese captain Xia Zhongyi, who has a prior record of smuggling agricultural products from Mainland China, and three Indonesian fishermen were allegedly controlled by drug cartels.

Taiwan authorities plan to follow up and expand the scope of their investigation.