The effects of unilateral conservation policies, such as marine protected areas (MPAs), national parks, and nature reserves, are not always straightforward. Policies that restrict productive effort in order to conserve species may push production overseas, which can increase greenhouse gas emissions. When overseas production coincides with the migration paths of target protected species, trade leakages in conservation can occur. We explore the issue of unilateral regulation and its effects on environmental quality by exploiting a series of seasonal and permanent closures of the swordfish (X. gladius) fishery along the West Coast of the US between 2001 and 2004. The closures were enforced through the Endangered Species Act due to recorded interactions with endangered leatherback (D. coriacea) and loggerhead sea turtles (C. caretta). We use an Inverse Almost Ideal Demand System coupled with vector autoregression to simulate counterfactual domestic and imported swordfish demand in absence of the policies. We find that not only did the the closures result in a reduction in welfare for West Coast swordfish consumers, but swordfish imports may have been approximately $500 thousand pounds lower in the following year in absence of the policy (11% of pre-2001 quantities, or 0.73 standard deviations). This suggests that domestic demand shifted to foreign fisheries, many of which are less regulated. Finally, we will estimate how realized landings and imports may have affected sea turtle bycatch in international fisheries as well as emissions via swordfish trade. Our results not only contribute to the large body of literature of the environmental impacts of trade leakages, but are a novel evaluation of the consequences of unilateral regulation to conserve transboundary species.