At about 8 pm on March 22, a joint patrol by waterway police and a rescue unit discovered the vessel, registered QN-2351-TS, operating near Con Cho Islet.
The boat was found transporting nine individuals fishing for squid in violation of regulations. It was operated by a 36-year-old man from Phong Coc Ward, who said he had been asked by the 35-year-old owner to look after the vessel.
He later invited friends on board and organised a squid fishing trip, piloting the vessel into the bay at around 5 pm before being detected by patrol forces.
Authorities have drawn up a report and impounded the vessel for further handling in line with regulations.
Earlier patrols had also uncovered and dealt with another case of illegal squid fishing in the area.