Port Noarlunga reef a most accessible window to marine wonders, from a beach only 34km south of Adelaide city

In 1994, the South Australian Research and Development Institute installed an underwater interpretation trail along the reef , off Port Noarlunga beach, with 12 concrete plinths on the seabed fitted with plaques giving information about the reef’s sub-tidal flora and fauna.
Images courtesy Trails SA (Port Noarlunga Reef Dive Trail)
Port Noarlunga reef, 34 kilometres south of Adelaide city off a beach in St Vincent Gulf, became South Australia’s most accessible place for scuba divers and snorkelers to see more than 200 species of marine plants and animals, and more than 50 fish species.
Port Noarlunga temperate reef system, 800 metres long in shallow water and exposed at low tide, could be approached from the beach or stairs on the 300 metres-long jetty. Accredited operators offered diving and snorkelling tours of the reef that also was the focus for scuba diving training in South Australia.
Port Noarlunga Reef Aquatic Reserve was declared in 1971 to protect “reef organisms from exploitation and for the conservation of the estuary and swamps of the lower Onkaparinga River, for the purposes of recreation and education". The reserve also protected the Horseshoe Reef off the coast at neraby Christies Beach.
From 2016, the aquatic reserve, an IUCN (International Union for Conservation of Nature) Category VI protected area, extended seaward for about 1.75 kilometres from Gulfview Road in the suburb of Christies Beach in the north and finishing in the south at the shoreline near the west end of Helmsman Terrace in the suburb of Seaford and including the whole Onkaparinga River from its mouth to the South Road bridge in the suburbs of Noarlunga Downs and Seaford Meadows. Fishing was limited to rod and handline except for the waters within 25 metres of Horseshoe Reef and 50 metres of the Port Noarlunga Reef. The use of hand nets to take shrimps for bait only was permitted in Oankaparinga River estuary.
In 1994, the South Australian Research and Development Institute installed an underwater interpretation trail at Port Noarlunga to raise community awareness of temperate reef environments and marine life. The trail over the reef's 800 metres had 12 concrete plinths installed on the seabed and each fitted with a plaque with information about the reef’s sub-tidal flora and fauna. The trail started at the jetty and went south on the east side of the reef and passed through The Gap in the reef and headed north on the reef's west side to a point opposite the end of the jetty.
From 2012, Port Noarlunga Reef Aquatic Reserve was within the Encounter Marine Park protected area taking in four habitat protection zones and two sanctuary zones including one extending along the coastline from Witton Bluff in the north and Onkaparinga Head in the south. Encounter Marine Park stretched from the base of the Fleurieu Peninsula to the north-eastern coast of Kangaroo Island and the Coorong.