Sharks, killer whales and disease are a threat to dolphins in the open oceans. But the greatest dangers come from humans. Toxic chemicals from industry and rubbish from our streets and homes pollute the Port River. Dolphins are injured by discarded fishing lines, hooks and nets. They can be cut by boat propellers, poisoned by bilge water and harassed by engine noise.

During Port Adelaide’s busiest era the waters were even more polluted and the traffic more dense than it is today. Some scientists believe dolphins were driven away altogether. Others think that numbers were simply reduced. The port is changing and there is a new interest in the natural world. It is up to us to improve the Port River dolphins’ environment.