I don't think that's the relevant difference between forestry and fishing. Forestry can be easily parceled out by plot in a way that fishing can't. Forests can be managed by giving one logging concern responsibility for a specific plot and holding them responsible for any overlogging in that area and for any mandated replanting.

Fishing has to be managed by enforcing quotas, this is a much more difficult problem even for a single government. I haven't done research in fishing, but do we see fishing being managed well in areas that are under the jurisdiction of one government or governments with good cooperation (like the great lakes)? Or for species that's habitat is within the coastal waters of one government?