https://en.wikipedia.org/wiki/Papua_New_Guinea_Defence_Force...: According to Janes the navy is badly underfunded and much of its equipment is in need of maintenance; as a consequence it is scarcely able to carry out its tasks, with operations often delayed or cancelled. The navy's patrol craft are barely effective; fuel costs and maintenance problems mean that often only one boat is available for sea duty at any time, while the heavy landing craft have high upkeep costs and are nearing the end of their service life. Although the patrol boats may be at times serviceable, the task of patrolling such a large Exclusive Economic Zone (EEZ) is too great and they are heavily reliant for information about the presence of foreign ships on daily reports supplied by US satellite surveillance. The main concern is illegal tuna fishing by Japanese vessels.
https://en.wikipedia.org/wiki/Solomon_Islands#Military: the country has not had any regular military forces since independence. The various paramilitary elements of the Royal Solomon Islands Police Force (RSIPF) were disbanded and disarmed in 2003 following the intervention of the Regional Assistance Mission to Solomon Islands (RAMSI). RAMSI has a small military detachment headed by an Australian commander with responsibilities for assisting the police element of RAMSI in internal and external security. The RSIPF still operates two Pacific class patrol boats (RSIPV Auki and RSIPV Lata), which constitute the de facto navy of Solomon Islands.
I suspect the other countries have similar military power.
Especially since I believe fishing fleets have centralized utility boats? Impound a processing & refrigeration ship... and what's the rest of the fleet going to do?
[Edit] US example: https://en.m.wikipedia.org/wiki/Naval_Ocean_Surveillance_Sys...
Also, apparently the ex-Soviet radar version with the brilliant idea of boosting their nuclear reactors into a higher orbit at EOL: https://en.m.wikipedia.org/wiki/US-A
While these vessels are out in international waters, one can't simply board/seize/sink such vessels without causing a major diplomatic incident with economic consequences at best. At worst, it would be perceived as an act of war and invite military response.
History has a lot of reprisal attacks too, vengeances etc. Not a road to go down lightly with any nation, let alone China.
IDK, I hesitate to call thinking that this is a simple or good idea "very American", but a certain sector of American internet forum commenting civilians do tend to think this way. Serious people, American or otherwise, not so much.
Or maybe ensnare the vessels, like the Tholians did to USS Enterprise. Defenders equip fast ships with spools of nylon. Race around the offenders, dragging the nylon, hoping to tangle their props. Mindful to stay out of gun shot range.
If I could hurt the Bad Guys, I would consider it. But from my reading of the popular press, many of the workers are victims too.