Reserves declared by the South Australian government Aquatic reserves Spencer Gulf contains four
aquatic reserves.
Blanche Harbour-Douglas Bank Aquatic Reserve which is located in west side of Spencer Gulf, north of Whyalla, was declared in 1980 'for fisheries management, protection of its mangrove-seagrass communities and associated fish nursery areas.'
Goose Island Aquatic Reserve which is located at
Goose Island on the east side of Spencer Gulf near Port Victoria was d eclared in 1971 to provide 'a conservation area where teaching institutions may conduct classes and scientific research on marine biology and ecology and to protect the habitat of the seal colony situated on White Rocks.'
Whyalla - Cowleds Landing Aquatic Reserve which is located on the west side of Spencer Gulf, just south of Whyalla, was declared in 1980 to 'protect the mangrove-seagrass communities and associated fish nursery areas.'
Yatala Harbour Upper Spencer Gulf Aquatic Reserve which is located in Yatala Harbour on the east side of Spencer Gulf, north of Port Pirie, was declared in 1980 for 'the protection of its mangrove-seagrass communities and associated fish nursery areas.'
Marine parks Spencer Gulf contains five
marine parks, each with its own outer boundary and internal zoning. Fishing is prohibited with Sanctuary Zones, and detailed maps and GPS coordinates for the parks are available from the Government of South Australia's Department of Environment, Water & Natural Resources. The marine parks within Spencer Gulf are (from north to south): •
Upper Spencer Gulf Marine Park •
Franklin Harbor Marine Park •
Eastern Spencer Gulf Marine Park •
Southern Spencer Gulf Marine Park Cuttlefish Coast Sanctuary Zone The Cuttlefish Coast Sanctuary Zone is within the Upper Spencer Gulf Marine Park. This area, south of Port Augusta and northeast of Whyalla, was inscribed on the
National Heritage List on 24 February 2023, as it is "of outstanding significance to Australia as the largest known breeding habitat of the giant Australian cuttlefish (
Sepia apama)". The rocky reef provides a protective shelter for the cuttlefish, which attach their eggs on the underside of rocks or in crevices. Within the sanctuary, the largest and densest breeding aggregation of cuttlefish in the world occurs annually from May to August, with intense competition between male cuttlefish leading to complex behaviours and spectacular massed displays of colour and shapeshifting. The cuttlefish in this area face several threats, including vulnerability to the impact of
commercial fishing. These risks are being managed by the
South Australian Government through protection in a marine protection area and fishing bans. Other possible risks are pollution from industrial sites or plastic pollution being washed in on the tide. In August 2025, the state and federal governments provided funding of almost $700,000 to install a
bubble curtain to protect the giant cuttlefish in the Upper Spencer Gulf during their breeding season from the
harmful algal bloom that began on the
Fleurieu Peninsula in March, and had not yet dissipated. The curtain would protect approximately 50,000 to 80,000 eggs and hatchlings. However, the bloom had not reached the Upper Spencer Gulf by October 2025.
Terrestrial reserves A number of terrestrial reserves either adjoin Spencer Gulf at
low water or are located on islands within the gulf. On the west coast of the gulf, from north to south, they are
Munyaroo Conservation Park,
Franklin Harbor Conservation Park,
Lipson Island Conservation Park,
Tumby Island Conservation Park,
Sir Joseph Banks Group Conservation Park,
Lincoln National Park and
Memory Cove Wilderness Protection Area. On the east coast of the gulf, from north to south, they are
Winninowie Conservation Park,
Bird Islands Conservation Park,
Goose Island Conservation Park,
Leven Beach Conservation Park and
Innes National Park. At the mouth of the gulf, the
Gambier Islands Conservation Park is located within the Gambier Islands group.
Non-statutory arrangements Important Bird Areas Three
Important Bird Areas (IBAs) have been nominated by
BirdLife International at locations in Spencer Gulf. The
Spencer Gulf Important Bird Area lies along the north-eastern coast of the Gulf; it comprises a strip of coastal land consisting mainly of
intertidal mudflats,
mangroves and
salt marshes. It was identified as an IBA by BirdLife International because of its importance for the conservation of
waders, or shorebirds. The other two IBAs within Spencer Gulf are located in the
Sir Joseph Banks Group and at
Goose Island. Both sites contain breeding colonies of various island seabird species. ==Gallery==