It doesn’t have to be capitalism. Ships from countries with other economic systems have and do participate in illegal fishing. If you have hungry people, unproductive land, and tapped out fisheries of your own it might be tempting to sail into your neighbors waters.
I'd assumed even (say) Chinese fishing fleets were capitalist enterprises. Are they government-owned, or are private-party to private-party transfers of fishing-related capital highly restricted?
Who could possibly even know for sure. But I think my point stands, as Vietnam has the 2nd or 3rd largest fishing fleet in the world right now, and for a few decades the Soviet Union was the 3rd largest. Pursuit of profit isn't the only reason for the tragedy of the fisheries held in common.