Tonga’s ocean environment is not the same everywhere. Some places are colder, some are deeper, some are more productive, some have more animals and plants. A globally unique hierarchical analysis was applied to Tonga’s ocean to describe draft marine bioregions that divided up the marine environment into places that were similar to each other and places that were different to each other. The analysis was first conducted for deepwater areas – thirty datasets were used for this. Then species-level fish, coral and other invertebrate data collected from over 6000 sites were modelled against seven environmental variables to describe reef-associated bioregions.
Tongan experts reviewed the resulting draft marine bioregions to end up defining 27 deepwater and four reef-associated marine bioregions for the country. These marine bioregions will form the basis of defining an ecologically representative network of marine protected areas within the Ocean Plan being developed for Tonga. The marine bioregions can also be used in other marine resource management decisions and planning.