Poaching is a major problem under the Chilean system of territorial use rights in fisheries (TURFs). Organizations of artisanal fishers that are granted spatial property rights through TURFs combat poaching by establishing their own enforcement. Although an organization must protect its benthic resources against poachers from both within the organization (“insiders”) and outside of the organization (“outsiders”), existing literature has shown that fishers are more concerned about enforcement against outsiders. Organizations know that their enforcement is imperfect - increasing enforcement increases the probability that poachers will be caught but does not guarantee that poachers will be caught. This probability depends on an “effectiveness of enforcement” parameter. With a high effectiveness of enforcement, an organization’s enforcement is more likely to lead to poacher capture. Using an optimal control framework, we analyze how a representative organization maximizes expected profit by choosing its levels of harvest and enforcement, over time. The organization incorporates the poacher’s best-response function, in which a poacher’s decision of how much to illegally harvest is influenced by the organization’s harvest and enforcement levels, the size of the stock, and exogenous parameters. In the case where the organization chooses positive levels of both harvest and enforcement, there are multiple equilibria in the steady state. One equilibrium is associated with a high level of stock while the other is associated with a low level. We show comparative dynamics on key parameters, including the effectiveness of enforcement.