Mud Island (Queensland)
From Wikipedia, the free encyclopedia
Native name: Bungumba | |
|---|---|
 Mud Island is located in Moreton Bay, near the Port of Brisbane  Mud Island (top right) is the terminus of a chain of islands extending from Wellington Point | |
 Interactive map of Mud Island | |
| Geography | |
| Location | Moreton Bay |
| Coordinates | 27°20′20″S 153°15′04″E / 27.3389°S 153.25111°E |
| Area | 4.24 km2 (1.64 sq mi) |
| Administration | |
Australia | |
| State | Queensland |
| LGA | Brisbane City Council (Wynnum-Manly) |
| Queensland State Electoral Division | Lytton |
| Federal Electoral Division | Bonner |
Mud Island is an intertidal saltmarsh island and conservation park located in Moreton Bay, South East Queensland.[1][2][3] Situated approximately 4km from the Port of Brisbane, the island is the largest in a chain that extends from Wellington Point, which includes King Island, Green Island and St Helena Island. The name is a misnomer, as the island is an intertidal mangrove reef composed primarily of coral.
Most of the island is submerged at high tide, with only a small fraction of the 4.24km2 area constitutively above the high-water mark. Although the island attracted protections in the early twentieth century, recognising it as a sanctuary for birds and fish, the surrounding reef was excavated as the result of decades of coral dredging by the Queensland Cement and Lime Company, significantly reducing its area. The island was designated as a conservation park in 2000.
The island is a vegetated reef primarily populated by mangroves.[3] As such, despite its name, the island's beaches are composed of coral. Prior to extensive dredging, the coral grew plentifully around the island - in 1932, Henry Richards described "excellent and quite extensive masses of growing coral" off the southern end. In 1938, Dorothy Hill visited the islands of Moreton Bay, including Mud Island and described the banks as 'fringing coral reef', with living coral below the low-water mark, shoaling 6-8 feet below.[4] The coral reserves were once so vast they were described as 'inexhaustible'.[5]
The island is known to be a sanctuary for birds, and hunting was prohibited as early as 1906.[6] Notable species of the island include the eastern great egret, white-bellied sea-eagle, grey-tailed tattler, little tern, grey plover and southern giant petrel. The endangered Far Eastern curlew is also found on the island.[7] Loggerhead sea turtles, dolphins, sharks and humpback whales can be seen around the island, as across the bay at large.[8]
Mud Island is part of the Moreton Bay Ramsar site, which is designated as a wetland region of international importance. Intertidal areas like the island are critical for the conservation of waterbirds and vulnerable mangrove ecosystems, in addition to providing important nursery conditions for fish and crustaceans.[9] It has long been regarded as a good fishing spot, particularly of Australasian snapper.[10][11] The island was gazetted as a conservation park in 2000 under the Nature Conservation Act 1992 (Qld).[7]
The island's geomorphology has been fundamentally altered by decades of coral dredging. Because so much of the subsurface reef has been removed, the island is surrounded by deeper water, leaving it exposed to stronger waves, and thus greater erosion. These waves also deposit coral rubble from the seafloor as 'ridges' surrounding much of the island. The coral ridges have been found to block intertidal drainage, resulting in mangrove mortality through ponding of water.[12][5] Fringe mangroves are especially vulnerable to smothering and abrasion as the result of these factors, and seaward areas have suffered significant erosion. The greater depth of the seafloor, along with significantly greater rates of fine sedimentation in the bay water, both the result of dredging and mangrove habitat erosion, have irreversibly damaged the ability of corals, algae and seagrasses to grow around Mud Island.[13] Substantial coral rubble remains on the seafloor, nearly 30 years after the conclusion of dredging.[14]
The tidal flux subjects the island and the surrounding reef to significant amounts of pollution and human refuse, in addition to marine debris like crab pots and netting. Cleaning is not undertaken as the island is very rarely visited.[15][16]
