Authorities have impounded ships and arrested foreign crew in waters around Riau Islands, not only for illegal fishing, but also for harassing local fishermen.
The intimidation campaign is thought to be retaliation for Indonesia's recent sinking of illegal ships.
The Maritime Affairs and Fisheries Ministry has reported the interception of three foreign fishing boats holding 43 foreign crew members in waters around Anambas and Natuna regencies in Riau Islands.
Those on board were detained on suspicion of intimidating local fishermen as well as fishing in Indonesian waters without a permit.
The ministry's director general of maritime resources and fishery supervision, Asep Burhanudin, told The Jakarta Post in Batam on Wednesday that the foreign vessels were intercepted based on a report by the Anambas Maritime Affairs and Fishery Agency to Maritime Affairs and Fisheries Minister Susi Pudjiastuti.
"The minister received a report regarding foreign fishermen intimidating local fishermen. So we followed it up by deploying the Hiu Macan 005 patrol vessel and was able to intercept the foreign vessels allegedly committing the intimidation acts," said Asep.
According to Asep, the first patrol action was conducted on March 7 against the Sudita 15 fishing boat, resulting in the confiscation of 800 kilograms of fish. Other actions were taken March 10 on a Seroja boat and upon a Serasi boat from Vietnam.
The Sudita 15 was impounded with 13 crew members aboard, all from Thailand. The Seroja and Serasi vessels were apprehended along with 15 Vietnamese crew members on each boat.
"The terror may be an act of reprisal by foreign fishermen against local fishermen over the recent sinking of foreign fishing vessels caught fishing illegally," said Asep.
He said the directorate general, through the provincial administration, had warned fishermen around the border to exercise more caution.
"We urge local fishermen not to sail out to sea alone and to be cautious in order to avoid threats from the foreign fishermen. The acts of intimidation could be anything, including killing," Asep said.
Asep claimed there had been a drastic decline in illegal fishing following the decisive action to ward off foreign vessels poaching in Indonesian waters.
The directorate general said the hundreds of illegal fishing boats have now been reduced to mere dozens.
Anambas chapter of Indonesian Fishermen Association (HNSI) head Tarmizi said several fishermen from Anambas had been harassed by foreign fishermen starting in December.
"Local fishermen have been chased and cornered by other boats, and this is obviously dangerous. The foreign fishermen also brandished sharp weapons. This has been taking place since the government began sinking foreign fishing boats," Tarmizi said.
According to Tarmizi, compared to local fishermen, foreign fishermen had larger vessels and more sophisticated equipment.
"Since the terror [started], we have steered clear of the fishing area, as it's too risky," he said.
Indonesian Navy Territorial IV main naval base commander Commodore Sulistiyono said Indonesian Navy patrol vessels had yet to encounter an incident, despite the many reports from local fishermen.
"We have positioned the KRI Pattimura in the waters where the threats from foreign fishermen are reportedly taking place, but have not yet encountered any incidents," said Sulistiyono.