The Port River estuary contains many different environments: creeks, inter-tidal salt marshes, sea grass meadows and water plants. It is one of the last grey mangrove ecosystems in Australia and is critical as the largest nursery for fish in South Australian waters. Most of the fish in South Australia’s oceans are spawned or live part of their lives here.  

Bottlenose dolphins (Yambo in the Kaurna language) have made their home in the estuary and surrounding oceans for thousands of years. Until European occupation the mangrove wilderness was a safe environment for dolphins. It was free of predators, abundant with fish and provided a safe haven for breeding dolphins and family groups.