Egg Island (Bass Strait) (23913)
Australia, Australasia
Site overview
KBA status: confirmed
Global KBA criteria: D1a
Year of last assessment: 2009
National site name: Egg Island (Bass Strait)
Central coordinates: Latitude: -41.1465, Longitude: 146.4260
System: marine, terrestrial
Elevation (m): 0 to 7
Area of KBA (km2): 0.1151
Protected area coverage (%): 95.95
KBA classification: Global
Legacy site: Yes
Site details
Site description: Egg Island is part of Horseshoe Reef, about 800 m off the coast north of the Devonport Airport in north Tasmania. The reef also comprises Wright Island and a number of small jagged rocks, totaling 10 ha at low water and less than 1 ha at high water. Egg Island is a flat-topped shingle bank about 3 m above high water, whereas Wright Island is a rocky ridge 1 m above high water. A large Black-faced Cormorant population breeds in three distinct colonies on the rocky northern shore, out of sight from the nearby mainland. Nesting Silver Gulls caused Devonport Port Authority to have concerns about potential bird strikes at Devonport Airport and birds were culled with baits about 20 years ago. Vegetation is a mixture of Australian Hollyhock, African Boxthorn and a few bushes of Myoporium sp.
Rationale for qualifying as KBA: This site qualifies as a Key Biodiversity Area of international significance that meets the thresholds for at least one criterion described in the Global Standard for the Identification of KBAs.
Additional biodiversity: Small numbers of Caspian Tern, Crested Tern, Pacific Gull, Little Penguin and Sooty Oystercatcher have bred in the past and probably continue to do so. Up to 2000 pairs of Silver Gull nested in 1966 (van Tets 1977) but numbers of this species have been lower in more recent years (E. Woehler in litt. 2009).
Other site values: Tasmania State Government. Permission should be sought from DPIW before visiting this Conservation Area.
Habitats
Land use: nature conservation and research (100%)
| IUCN Habitat | Coverage % | Habitat detail |
|---|---|---|
| Marine Coastal/Supratidal | 100 |
Threats
Summary of threats to biodiversity at KBA: Investigate the impacts of gill nets and disturbance from visitors and ships on numbers and breeding success of cormorants. Further poisoning of Silver Gull is a potential problem for nesting Black-faced Cormorant.
| Threat level 1 | Threat level 2 | Threat level 3 | Timing |
|---|---|---|---|
| Biological resource use | Fishing & harvesting aquatic resources | Unintentional effects: large scale (species being assessed is not the target) [harvest] | Ongoing |
| Invasive & other problematic species, genes & diseases | Invasive non-native/alien species/diseases | Named species | Ongoing |
| Transportation & service corridors | Shipping lanes | Ongoing |
Additional information
References: Brothers, N., Pemberton, D., Pryor, H. and Halley, V. (2001) Tasmania's Offshore Islands: seabirds and other natural features. Tasmanian Museum and Art Gallery: Hobart. van Tets, G.F. (1977) Seabird Islands No. 50: Wright & Egg Islands, Horseshoe Reef, Tasmania. Corella 1: 63-64.
Contributors: The nomination was prepared by Peter Britton and Rachael Alderman and Rosemary Gales of DPIW and Eric Woehler kindly commented on the nomination. Anthony Timmerman, Mark Fordham and Peter Tonelli (Tasmanian Parks & Wildlife Service) and Frank Bingham (formerly of RSPCA) have advised on past and potential culling of Silver Gull by Devonport Port Authority.