Policing the lobster commons

Lobsters are caught in traps that sit on the sea floor, marked by (and recovered via) buoys that float above, connected to the trap by a rope. Lobstermen in Maine are known for policing who sets traps where by cutting the lines (or threatening to cut the lines) of lobstermen who set traps outside of their territory. From time to time there's a question about whether the state should limit certain areas to local lobstermen. Now is such a time:

In Maine, Tensions Over Ailing Lobster Industry
"Officially, anyone with a Maine lobster license can set traps almost anywhere in state waters. Most lobstermen are allowed 800 traps each, making for a crowded ocean floor.
But unofficially, each harbor has its own boundaries, determined by local lobstermen over the decades. Newcomers often find their buoys snatched or their trap lines cut. The lobstermen who live on Maine’s rugged islands are especially territorial and known for practicing frontier justice; in one notorious case in 2000, two lobstermen fought over turf with a pitchfork and a fish gaff."
...
"The idea of a resident-only lobstering zone is not without precedent. The state approved a two-mile “conservation zone” around Monhegan Island in 1998, restricting access to local lobstermen, who had complained about interlopers from the mainland. "
...
"George Lapointe, the state’s commissioner of marine resources, said he had not yet decided whether to endorse a resident-only zone for Matinicus and had to consider the constitutional rights of all of the state’s roughly 5,800 licensed lobstermen.
“I’ve had three other islands say they’re interested in getting their own zone if we create one for Matinicus,” Mr. Lapointe said. “One of the concerns is the balkanization of lobster territories along the coast.”
He said that enforcing the zone around Monhegan had proved expensive for the state, and that while the shooting on Matinicus had put the island’s problems under a magnifying glass, lobstermen up and down Maine’s coast were hurting."