Otago Harbour is a long, sheltered tidal harbour stretching 21 kilometers along the Otago Peninsula from the city of Dunedin to the open South Pacific Ocean. It is a highly productive marine environment known for its clear waters and strong tidal currents that sweep rich marine life through its narrow, deep shipping channel. The harbour's western side features a deeper channel, while the eastern side is shallower with large sandbanks exposed at low tide. The harbour is dotted with numerous bays and islands, including Quarantine Island and Goat Island, and is fed by freshwater inputs like the Water of Leith at its southern end, which slightly lowers salinity in that area. This diverse habitat supports a robust recreational fishery right on Dunedin's doorstep, with relatively light fishing pressure compared to other urban harbours.