Dynamics of a renewable resource is considered in a region which is divided into two patches. The intrinsic growth rate of the resource in both the patches is taken to be the same and the diffusion of the resource between the patches depends on the density difference of the resource between the patches and the mobility characteristics of the resource. It is assumed that one of the patches is a no-take reserve and the other one is used for harvesting the resource. The dynamics of the resource in these two patches is described using a realistic coupled differential system. The bio-economics of this resource is studied by solving an optimal harvesting problem from a sole owner prospective. The analysis gives rise to an expression, called as efficacy term, given in terms of the division of the patch and the diffusive characteristic of the resource, using which the role of the no-take reserve on the bio-economics of the resource can be identified. These results can also be used to decide upon the appropriate division of a region given resource characteristics or vice versa in order to optimize revenue to the harvester. The results obtained match with the opinions of several natural and social scientists and also support some experimental observations.