The following paper: Place-based approaches to marine mammal conservation by Giuseppe Notarbartolo di Sciara, Erich Hoyt, Randall Reeves, Jeff Ardron, Helene Marsh, Dag Vongraven and Bradley Barr Aquatic Conservation: Marine and Freshwater Ecosystems 26 (Suppl. 2):85-100 DOI: 10.1002/aqc.2642 This Special Issue of Aquatic Conservation is dedicated to results from the World Parks Congress, Sydney, December 2014: http://onlinelibrary.wiley.com/doi/10.1002/aqc.v26.S2/issuetoc <http://onlinelibrary.wiley.com/doi/10.1002/aqc.v26.S2/issuetoc> All papers in the Special Issue are open access. Abstract. 1. Place-based conservation can be an effective tool for addressing threats to marine mammals, but this approach presents many challenges, such as the dilemma of whether to aim for protection at appropriately large scales or through networks of smaller protected areas, and how to address the socio-economic conditions of human societies whose welfare may conflict with marine mammal survival. 2. Protecting places to conserve marine mammals started about 50 years ago, when the first parks and reserves were established to protect the critical habitat of specific populations. However, the challenges of protecting habitats that cross national borders and span oceans including the high seas remain problematic. International cooperation is needed, e.g. within the framework of multilateral environmental agreements such as the Convention on Biological Diversity (CBD) and the Convention on Migratory Species (CMS), as well as a potential new agreement through the UN Convention on the Law of the Sea (UNCLOS). 3. Increasingly, the process of demarcating Marine Protected Areas (MPAs) is being supported by other spatial designations, including CBD’s Ecological or Biologically Significant Areas (EBSAs), the International Maritime Organization’s Particularly Sensitive Sea Areas (PSSAs), IUCN’s Key Biodiversity Areas (KBAs), and Biologically Important Areas (BIAs) adopted by the USA and Australia. Recently, the Important Marine Mammal Areas (IMMA) designation has been introduced by the IUCN Task Force on Marine Mammal protected Areas. Such approaches have the potential to increase the protection of marine mammals within the overarching approach of systematic marine spatial planning. 4. Considering the attributes of marine mammals as sentinel, umbrella and flagship species, it is likely that emerging place-based approaches that incorporate IMMAs will not only benefit marine mammal populations, but also contribute more generally to the conservation of marine and aquatic species and ecosystems. Giuseppe Notarbartolo di Sciara