Chittagong Port Authorities, the navy and coastguards have launched a joint operation to clear fishing nets blocking vessel routes in the port channel and outer anchorage.

The move came after the Bangladesh Lighterage Workers Union gave the port chairman an ultimatum to act by Aug 17.

On Wednesday, 24 fishermen were detained for allegedly setting nets in the navigation channel and each was sentenced to one month in jail by a mobile court.

The union has repeatedly complained that nets laid across the Karnaphuli River and Bay of Bengal obstruct vessels and can become entangled in the propellers of larger ships.

Union President Md Mizanur Rahman said nets can stop a ship’s engine and lead to accidents.

He alleged that when lighter vessels become trapped, fishermen sometimes throw stones at them or attack with machetes and other sharp weapons.

He also alleged that those who cut the nets to free a propeller are sometimes asked for large compensation, with some groups resorting to robbery and threats.

A shipping company official said nets and boats placed along routes, particularly at night, are disrupting navigation and increasing collision risks.

The union had sent three letters to the port chairman since August last year, warning that workers would halt vessel movement if the nets were not removed by Aug 17.

In a public notice on Wednesday, the port authority said unauthorised vessels and illegal fishing in commercial shipping routes were prohibited and increasing accident risks.

Port Executive Magistrate Sadia Afrin said the 24 fishermen were jailed under the Inland Navigation Ordinance.

“Operations will continue to stop this practice,” she said.

Port Secretary Syed Refayet Hamim said keeping waterways safe was an ongoing process and further operations would continue.