The Pauatahanui Inlet is the eastern arm of the Porirua Harbour. Adjacent suburbs are, clockwise from the east, Pauatahanui, Whitby, Paremata (containing the entrance/exit under the rail and road bridges), and Camborne. It is less polluted than the south-western arm. Its "guardins" say it is "the only large estuarine wetland left in the lower half of New Zealand's North Island". A study some decades ago found world-clsss densities of copepods, one of the building-blocks in the marine food chain.