Interventions can backfire
Interventions aimed at increasing fishers' profit margins (e.g. by providing subsidized fishing gear, facilities, and so on) can result in new fishers joining the fishery from other vulnerable regions. Even though supporting more fishers is a social benefit at the national level, the added effort threatens fish stocks. In the long run, it is very easy for productivity-aimed interventions to disrupt the stock-fishers equilibrium, leading to a stock collapse and thus having an overall negative effect in the end.