The extensive river and creek estuaries within the Great Sandy Marine Park, combined with the sheltered environment of the Great Sandy Strait, provide large areas of ideal habitat for mangroves. Mangroves ‘kick start’ many coastal food chains. Some nutrients are used on the spot, while others are exported with the tides to neighbouring seagrass beds and beyond. At some time in their lives, more than 70 per cent of the commercial and recreational fisheries species depend on mangroves. For example, barramundi spawn in mangrove creeks protected from predators.
Mangrove communities act as stabilisers, which help to reduce excessive sediment flow. They are of particular importance as they form a protective barrier trapping sediments and stabilising shore and river edges, decreasing the threat of erosive action by currents and stream flow.
There are 10 mangrove species found in the Great Sandy Marine Park which include:
- Grey mangrove (Avicennia marina)
- River mangrove (Aegiceras corniculatum)
- Club mangrove (Aegialitis annulata)
- Large leaf orange mangrove (Bruguiera gymnorhiza)
- Smooth fruit orange mangrove (Ceriops australis)
- Milky mangrove (Excoecaria agallocha)
- White-flowered black mangrove (Lumnitzera racemose)
- Myrtle mangrove (Osbornia octodonta)
- Long style stilt mangrove (Rhizophora stylosa)
- Cannonball mangrove (Xylocarpus granatum)
Some of the mangrove habitats in the marine park include:
- Mary River – extensive mangrove forests line the mouth of the river and its banks
- Islands – there are numerous mangrove dominated islands throughout the Great Sandy Strait
- Creeks – most creek lines throughout the marine park are lined with mangroves to their tidal extent.
Unusual tenants of the mangroves
The water mouse (Xeromys myoides), a protected species, builds large mud nests in mangrove forests and feeds on small crabs and molluscs. Nest structures have been observed at a number of locations within the Great Sandy Strait and Tin Can Inlet. In hollow branches of grey mangroves, the threatened Illidge’s ant-blue butterflies (Acrodipsas illidgei) trick ‘crematogaster’ ants into feeding their own young to the butterfly’s caterpillar.
- Read more about mangroves.
- Tobruk Public Mooring Closed 3 June to 31 July 2021