[Rockingham]

Interdiction of ships can be hard, as in a physical stop at sea, or soft, via fines, financial sanctions, and port-side arrests and seizures of ships, owners, crews, and commercial partners. Close observation and infrastructure already in place makes the Baltic the place to start, with Murmansk and Vladivostok to follow. Russia would have no answer to that.

China can also be threatened with financial sanctions on any banks or companies that do business with Russia. They would watch the development of an effective soft interdiction regime against Russia with alarm as dangerous experience and precedent for use against China.

The loss of most sea trade in bulk cargoes would have a devastating effect on the Russian economy.

[NorseViking]

You can’t arrest ships that do not visit your ports. If you plan to do it on high seas, they will either.