It looks like supply and demand are the main weapons. See Cheap Maine lobsters spark protests in Canada. Excerpt:
"Maine-caught lobster, whose abundance this summer has driven prices here to the lowest levels in a generation, has sparked angry protests among lobstermen in New Brunswick.
Fishermen in Cap-Pele, New Brunswick, blocked access to several processing plants Thursday to protest an influx of Maine lobster after being told they would be expected to provide fewer lobsters when their season opens next week.
Maine truck driver Leonard Garnett of Steuben talks with police at a Shediac, New Brunswick, processing plant after fishermen blocked his truck with the intention of leaving his load of lobsters to rot.
On Thursday morning, emergency tactical police teams responded to calls for help from two lobster processing companies in Cap-Pele, a small French-speaking town on the Northumberland Strait, 200 miles east of Calais.
The police encountered about 200 lobstermen and followed them as they moved from one plant to the other, demanding that the owners stop processing U.S. lobster, the CBC reported.
Both plants were reportedly closed, with workers sent home.
At midday, lobstermen in nearby Shediac spotted a tractor-trailer truck with Maine plates carrying a load of lobsters, according to the CBC, and blocked it in a driveway with the intention of leaving the lobsters to rot.
The blockades followed a meeting Wednesday night called by the Maritime Fishermen's Union, at which 400 lobstermen commiserated about cheap soft-shell lobsters from Maine that are flooding local processing plants before the opening of their summer fishing season.
Reports say they expressed concern that Maine lobster -- for which lobstermen are getting well under $3 a pound -- will undermine demand and prices for locally caught lobster."