Abstract A marine protected area (MPA) is an area of the ocean designated for the conservation and protection of natural or cultural resources. MPAs are spatial tools used to preserve the ecological integrity and biodiversity of an area, protecting ecosystem functions, species and habitats for future generations. In 2015, the Canadian government committed to increasing protection of its coastal and marine areas up to 10% by 2020. To reach this goal, the Federal Department of Fisheries and Oceans (DFO) is currently in the process of designing and implementing a network of MPAs in the Maritimes Region, on the Atlantic coast of Canada. The design process needs to consider population connectivity, which in turn requires an understanding of life-histories for target species (i.e. the movement of adults and the dispersal of larval life-stages). The population parameters that repeatedly emerge as necessary for deriving estimates of MPA dimensions include the spatial distribution of the conservation priority (species or habitat), movement patterns and oceanographic processes. A decision tree was developed that uses information on species larval dispersal, and juvenile, and adult movement to provide guidelines that can inform definition of size and spacing of individual MPAs in a network. Case studies of species targeted for protection on the Scotian Shelf are presented, to illustrate its use. The decision tree can be used as a tool to help design networks that ensure population connectivity where there is a paucity of biological information, or as a quality control method for assessing other spatial design tools.