Pelagic provinces of the world: A biogeographic classification of the world's surface pelagic waters

Off-shelf waters cover 66% of the planet. Growing concerns about the state of natural resources in these waters, and of future threats have led to a growing movement to improve management and conservation of natural resources. However, efforts to assess progress and to further plan and prioritise management interventions have been held back in part by the lack of a comprehensive biogeographic classification for the high seas. In this work we review existing efforts at classifying the surface pelagic waters of the world's oceans and we present a synthesis classification which draws both on known taxonomic biogeography and on the oceanographic forces which are major drivers of ecological patterns. We describe a nested system of 37 pelagic provinces of the world, nested into a system of four broad realms. Ecologically we have also differentiated a system of 7 biomes which are spatially disjoint but united by common abiotic conditions creating physiognomically similar communities. This system builds on existing work and is further intended to align closely with the coastal biogeographic regionalisation provided by the Marine Ecoregions of the World classification. It is hoped that it will provide a valuable tool in supporting threat analysis, priority setting, policy development and active management of the world's pelagic oceans.