While marine ecosystems are generally more spatially and temporally complex than terrestrial ecosystems, the general principles for determining where to prioritise resources for an MPA should follow the same as those for terrestrial biodiversity. This implies identifying areas with: 1) the highest biodiversity benefits: 2) the highest risk of loss, and 3) the lowest opportunity costs (see OECD, 2010). This helps to ensure that the greatest benefits can be achieved given the resources available. As noted by Watson et al. (