Marine protected areas (MPAs) that ban fishing restore marine life within their boundaries and can also replenish nearby fisheries. However, some argue that after large MPAs are established, fishing effort is displaced to unprotected areas and economic loss is incurred by the fishing industry. We tested these assumptions by assessing the behavior and productivity of the Mexican industrial fishing fleet before and after the implementation of the largest fully protected MPA in North America (the 147,000-square kilometer Revillagigedo National Park). We found no decrease in catches and no causal link between the variation of the spatial footprint of the industrial fleet and the implementation of the MPA. Our findings add to growing evidence that well-designed MPAs benefit marine ecosystems and, in the long term, can also benefit the fisheries they support.