A realignment of marine biogeographic provinces with particular reference to fish distributions

Marine provinces, founded on contrasting floras or faunas, have been recognized for more than 150 years but were not consistently defined by endemism until 1974. At that time, provinces were based on at least a 10% endemism and nested within biogeographic regions that covered large geographic areas with contrasting biotic characteristics. Over time, some minor adjustments were made but the overall arrangement remained essentially unaltered. In many provinces, data on endemism were still not available, or were available only for the most widely studied vertebrates (fishes), a problem that is ongoing. In this report we propose a realignment for three reasons. First, recent works have provided new information to modify or redefine the various divisions and to describe new ones, including the Mid-Atlantic Ridge, Southern Ocean, Tropical East Pacific and Northeast Pacific. Second, phylogeographic studies have demonstrated genetic subdivisions within and between species that generally corroborated provinces based on taxonomic partitions, with a notable exception at the Indian-Pacific oceanic boundary. Third, the original separation of the warm-temperate provinces from the adjoining tropical ones has distracted from their close phylogenetic relationships. Here we propose uniting warm-temperate and tropical regions into a single warm region within each ocean basin, while still recognizing provinces within the warm-temperate and tropical zones. These biogeographic subdivisions are based primarily on fish distribution but utilize other marine groups for comparison. They are intended to demonstrate the evolutionary relationships of the living marine biota, and to serve as a framework for the establishment of smaller ecological units in a conservation context.