North Island (Houtman Abrolhos)
Geography | |
---|---|
Location | Indian Ocean, off the coast of Western Australia |
Coordinates | 28°18′9″S 113°35′41″E / 28.30250°S 113.59472°E[1] |
Archipelago | Houtman Abrolhos |
Area | 180 ha (440 acres) |
Length | 2 km (1.2 mi) |
Width | 1.5 km (0.93 mi) |
Highest elevation | 13 m (43 ft) |
Highest point | Record Hill |
Administration | |
Australia | |
State | Western Australia |
Demographics | |
Population | Seasonally inhabited by about 130 lobster fishers (2003) |
North Island is the northernmost island in the
First recorded and surveyed in 1840, North Island has been a seasonal camp for
History
Discovery
The earliest recorded sighting of North Island occurred in May 1840, during the third survey voyage of HMS Beagle, commanded by John Clements Wickham. It was sighted from the peak of Flag Hill on East Wallabi Island in early May, explored on 22 May, and given its name due to "its relative position to the remainder of Houtman's Abrolhos". Before he left the island, Wickham left a letter in a bottle atop the highest hill, which he accordingly christened Record Hill.[2]
A map of the island first appeared in 1845 on a
"The island was about a mile across, and nearly circular. It was surrounded by a range of hills, with a flat in the centre, covered with coarse grass, where a great many quails were flushed, affording good sport, but not a single wallaby."
Development of industry and infrastructure
A
Visits by naturalists
A number of naturalists have visited the island, starting with the
Australian ornithologist
Geography
Nominally located at 28°18′9″S 113°35′41″E / 28.30250°S 113.59472°E,[1] North Island is an isolated island, separated from its nearest neighbours in the Wallabi Group by the 14 km (9 mi) wide South Passage. Despite this separation, it is sometimes treated as part of that group. It is roughly diamond-shaped and is approximately 2 km (1+1⁄4 mi) long from south to north, and 1+1⁄2 km (1 mi) from west to east,[12] giving it an area of about 180 hectares (450 ac).[5]
Two high points are named Record Hill and Latitude Hill. These are the only gazetted places on the island, although some other features have informal names: The most northerly and southerly point on the island have been called "North Point" and "South Point" respectively, and in 1960 a high point in the northwest corner of the island was referred to as "Northwest Hill".[5]
On the eastern side is a seasonally inhabited permanent fishers' camp. There is an unnamed lighthouse on the western side, a
The island is surrounded by a coral reef flat. This extends about 1+1⁄2 km (1 mi) to the west of the island, and over 3 km (2 mi) to the north and south, but the reef margin lies quite close to the island on the eastern side. Most of the reef is not navigable, but a passage through the reef just north of the island is named Suda Bay Passage; one just south of the island is named Barker Passage; and there are a few breaks or channels on the eastern side of the island where boats may obtain shelter in bad weather.[7] An area of reef immediately north of the island is named The Flat, and at the northern extreme of the reef is a breaker named The Big Breaker.[13] About 200 m (660 ft) west of the island is a small rock informally known as "Shag Rock", but with no official name; it differs from Shag Rock in the Wallabi Group further south.
Like the rest of the
Geology and physiography
The
North Island's basement for the most part does not exceed 1.5 m (4 ft 11 in) in elevation. Much of it is capped by
There are extensive dunes of unconsolidated Holocene sand along both the western and eastern sides of the island. The topography of these dunes varies with time: in 1913, Dakin recorded the dunes as being a good deal higher in the east than in the west,[7] but in 1960 Storr found the eastern dunes to be severely eroded, apparently because of a fire that burnt much of the island's vegetation in 1935.[5] In the centre of the island is a low plain with a sinkhole in its southwest corner and a small salt lake near its northern edge. The soil in the centre of the plain is shallow loam, whereas the rim is deeper and composed largely of shell fragments.[5]
Climate
An
Eighty-six percent of the island's rain falls between April and September; on average there are 89 rain days, resulting in 469 mm (18 in) of rain. The wettest month is June, when over 100 mm (4 in) typically falls. In contrast, only about 70 mm (3 in) can be expected to fall between October and March.[19]
It is nearly always windy. During summer a high-pressure ridge lies to the south, causing persistent winds from the southeast or southwest at speeds exceeding 17 kn (31 km/h) almost half the time. During autumn and winter, the ridge moves north, increasing atmospheric pressure over the islands and creating variable winds. Winter tends to produce both the strongest gales and the most frequent periods of calm. In addition to these winds, there is daily pattern of land breezes in the morning, followed by the onset of south-westerly sea breezes in the afternoon. This pattern is caused by temperature differences between the land and the ocean; it is not as strong in the Houtman Abrolhos chain as on the mainland, but is present.[19]
Three classes of storm have been identified in the region. Brief squalls may occur between December and April. A
Climate data for North Island (28º20'S, 113º35'E, 2 m AMSL) (2000-2024 normals and extremes) | |||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
Record high °C (°F) | 38.5 (101.3) |
41.0 (105.8) |
39.1 (102.4) |
34.5 (94.1) |
29.4 (84.9) |
27.1 (80.8) |
26.6 (79.9) |
27.2 (81.0) |
31.1 (88.0) |
33.4 (92.1) |
34.0 (93.2) |
39.4 (102.9) |
41.0 (105.8) |
Mean daily maximum °C (°F) | 27.7 (81.9) |
28.5 (83.3) |
28.2 (82.8) |
26.3 (79.3) |
24.4 (75.9) |
22.3 (72.1) |
21.2 (70.2) |
21.6 (70.9) |
22.3 (72.1) |
23.5 (74.3) |
25.3 (77.5) |
26.8 (80.2) |
24.8 (76.7) |
Mean daily minimum °C (°F) | 21.4 (70.5) |
22.0 (71.6) |
22.0 (71.6) |
20.4 (68.7) |
18.4 (65.1) |
16.5 (61.7) |
15.4 (59.7) |
15.4 (59.7) |
16.0 (60.8) |
17.2 (63.0) |
18.5 (65.3) |
20.1 (68.2) |
18.6 (65.5) |
Record low °C (°F) | 15.7 (60.3) |
17.2 (63.0) |
15.4 (59.7) |
13.1 (55.6) |
7.9 (46.2) |
7.1 (44.8) |
6.2 (43.2) |
6.8 (44.2) |
8.1 (46.6) |
9.7 (49.5) |
11.5 (52.7) |
15.1 (59.2) |
6.2 (43.2) |
Average precipitation mm (inches) | 2.3 (0.09) |
10.5 (0.41) |
5.6 (0.22) |
14.9 (0.59) |
40.3 (1.59) |
62.6 (2.46) |
66.1 (2.60) |
36.5 (1.44) |
19.0 (0.75) |
8.2 (0.32) |
6.9 (0.27) |
3.5 (0.14) |
273.1 (10.75) |
Average precipitation days (≥ 1 mm) | 0.4 | 0.9 | 1.0 | 2.2 | 5.7 | 8.4 | 8.8 | 6.4 | 3.4 | 1.7 | 1.3 | 0.6 | 40.8 |
Average afternoon relative humidity (%)
|
63 | 63 | 62 | 61 | 58 | 55 | 56 | 56 | 56 | 58 | 58 | 60 | 59 |
Average dew point °C (°F) | 17.9 (64.2) |
18.6 (65.5) |
17.9 (64.2) |
16.4 (61.5) |
14.1 (57.4) |
11.2 (52.2) |
10.3 (50.5) |
10.5 (50.9) |
10.9 (51.6) |
12.5 (54.5) |
14.5 (58.1) |
16.0 (60.8) |
14.2 (57.6) |
Source: Bureau of Meteorology[20] |
Flora
Most of North Island is dominated by
The rim of the central plain is vegetated by a dense shrubland of
The dune, limestone and salt lake vegetation communities on North Island are considered to have high conservation significance. The dune and limestone communities have high biodiversity, are highly sensitive to disturbance and regenerate slowly. The salt lake community is considered significant because of the rarity of salt lakes on offshore islands.[21]
According to a survey published in 2001, the following
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Fauna
Mammals
No land mammals are known to be native to North Island, but the Australian sea lion (Neophoca cinerea) occasionally hauls out on the island's beaches, and it has been suggested that the island once had a native population of tammar wallaby (Macropus eugenii).
Stokes explicitly stated the tammar wallaby to be absent from North Island in 1840,
In 1985, five tammar wallabies were introduced onto North Island, and the population established successfully. Possible reasons for this success include the absence of the wallabies' natural predator, the carpet python (
The only other mammal known to occur on the island is the naturalised house mouse (Mus Musculus).[23] Eight European rabbits (Oryctolagus cuniculus) were introduced in 1934, and were found to be "exceedingly numerous" by 1945, but by 1960 they were extinct, apparently from predation by feral cats.[5] Neither rabbits nor cats are now reported as naturalised on the island.[23]
Reptiles
Reptiles recorded on North Island include
The
Birds
The birds most often mentioned in relation to North Island are the Abrolhos painted buttonquail (Turnix varius scintillans), a rare subspecies of the widespread painted buttonquail (Turnix varius) known only from the Wallabi Group and protected under the Wildlife Conservation Act 1950; and the brush bronzewing (Phaps elegans), one of the most common birds on North Island, the mainland populations of which are decreasing.[21]
Other birds known to breed on North Island include the osprey (Pandion haliaetus cristatus), greater crested tern (Thalasseus bergii),[21] Caspian tern (Hydroprogne caspia), silver gull (Chroicocephalus novaehollandiae novaehollandiae), and welcome swallow (Hirunda neoxena). Birds commonly recorded as resident on the island but not recorded as breeding there include the Pacific reef heron (Egretta sacra), white-bellied sea eagle (Haliaeetus leucogaster), red-capped plover (Charadrius ruficapillus), fairy tern (Sterna nereis nereis), Australian pipit (Antus australis) and western silvereye (Zosterops lateralis chloronotus). The sooty oystercatcher (Haematopus fuliginosus fuliginosus) and white-backed swallow (Cheramoeca leucosterna) have also rarely been observed as resident on the island.[9]
The most common visitors to the island are the
North Island is part of the Houtman Abrolhos Important Bird Area, identified as such by BirdLife International because of its importance for supporting large numbers of breeding seabirds.[30]
Human uses
The entire Houtman Abrolhos is protected by an A-class nature reserve that is wholly vested in Western Australia's Minister for Fisheries for purposes of "Conservation of Flora and Fauna, Tourism, and for Purposes Associated with the Fishing Industry".[16]
Fishing industry
North Island's primary human use is as a seasonal camp for Western Rock Lobster fishers. During lobster season, which runs from 15 March to 30 June,[31] North Island's camp is occupied by about 130 fishers.[6] The camp is serviced by a carrier boat, the North Islander, which visits the island every three days, bringing supplies and taking out the catch and any domestic waste.[32]
Conservation
North Island is considered to have high conservation value with respect to its populations of brush bronzewing and Abrolhos painted buttonquail, and its dune, limestone and salt lake vegetation communities. The potential existence of historically significant artefacts on Record Hill, namely the bottle left by Wickham and Stokes in 1840, has not been assessed.[21]
A 514 ha (1,270 acres) area of reef immediately south of North Island is designated a Reef Observation Area (ROA). Fishing is prohibited in this area, except for the use of lobster pots. One of four ROAs in the Houtman Abrolhos, these protected areas are intended to help conserve species of territorial fish that are fished elsewhere, and to provide divers with the opportunity to observe large populations that are not frightened by their approach.[33]
Tourism
With extensive sand beaches, seabird breeding areas, and good
References
- ^ a b Gazetteer of Australia (1996). Belconnen, ACT: Australian Surveying and Land Information Group. A less precise but more up-to-date record is available online at "North Island". Gazetteer of Australia online. Geoscience Australia, Australian Government.
- ^ a b c Stokes, John Lort (1846). Discoveries in Australia. Vol. 2. London: T. and W. Boone.
- ISBN 0-9594105-6-2.
- ^ Bertelsen, Ron (23 October 1996). "Crayfishing at North Island... the Early Days". Midwest Times. p. 9.
- ^ Journal of the Royal Society of Western Australia. 43: 59–62.
- ^ a b c d e f g Morris, Keith; et al. (2003). A Report on the Management of Tammar Wallabies on North Island, Houtman Abrolhos (Report). Department of Conservation and Land Management, Western Australia.
- ^ .
- .
- ^ a b c Storr, G. M., Johnstone, R. E. and Griffin, P. (1986). "Birds of the Houtman Abrolhos, Western Australia". Records of the Western Australian Museum (Supplement No. 24).
{{cite journal}}
: CS1 maint: multiple names: authors list (link) - Corella. 18 (4): 97–113.
- ^ a b Harvey, J. M.; et al. (2001). "A flora and vegetation survey of the Houtman Abrolhos, Western Australia". CALMScience. 3 (4): 521–623.
- ^ Google Earth. Retrieved 2008-03-2008.
- ^ a b Australia 1:100000 Topographic Survey, Map sheet 1641 (Edition 1): Wallabi
- ^ "Electoral Division of Durack". Australian Electoral Commission. Retrieved 2 September 2009.
- ^ "Electoral District Boundaries: Technical Descriptions" (PDF). 10 October 2011. p. 20. Retrieved 15 December 2015.
- ^ a b "Management of the Houtman Abrolhos System: A Draft Review 2007–2017" (PDF). Fisheries Management Paper No. 220. Department of Fisheries, Government of Western Australia. 2007. Retrieved 1 December 2007.
- ^ Collins, Lindsay B.; et al. (1998). "Late Tertiary-Quaternary geological evolution of the Houtman Abrolhos carbonate platforms, northern Perth Basin". In Purcell, R.; Purcell, P. (eds.). The Sedimentary Basins of Western Australia. Vol. 2. Perth, Western Australia: Petroleum Exploration Society of Australia. pp. 647–663. Archived from the original on 22 July 2008. Retrieved 2 May 2008.
- ISBN 9780444516442.
- ^ a b c d Pearce, A. F. (1997). "The Leeuwin Current and the Houtman Abrolhos Islands, Western Australia". In Wells, F. E. (ed.). The Marine Flora and Fauna of the Houtman Abrolhos Islands, Western Australia. Vol. 1. Perth: Western Australian Museum. pp. 11–46.
- ^ "Climate Statistics for North Island". Climate statistics for Australian locations. Bureau of Meteorology. Retrieved 23 April 2016.
- ^ ISSN 0819-4327.
- ^ Main, Albert Russell (1961). "The occurrence of Macropodidae on islands and its climatic and ecological implications". Journal of the Royal Society of Western Australia. 44 (3): 84–89.
- ^ a b c Burbidge, A. A. (2004). "Introduced Mammals on Western Australian Islands: Improving Australia's Ability to Protect its Island Habitats from Feral Animals". Final Report for the Australian Government Department of the Environment and Heritage. Department of Conservation and Land Management, Government of Western Australia. Retrieved 13 August 2009.
- ^ a b c "'Pill' plan for growing wallaby population". ABC News. ABC News Online. 16 June 2005. Retrieved 2 April 2012.
- ^ a b "Wallabies – Culling" (PDF). Minutes of the Western Australian Legislative Council, Tuesday 19 February 2008. Retrieved 13 August 2009.
- ^ "Management of overabundant marsupials – North Island tammar wallaby case study" (PDF). Science Division Annual Research Activity 2006–2007 (Report). Department of Environment and Conservation, Government of Western Australia. pp. 83–84. Retrieved 25 November 2017.
- ^ "Herpetofauna Assessment of Long Island, Wallabi Group – 8 November 2005" (PDF). Archived from the original (PDF) on 14 July 2009. Retrieved 13 August 2009.
- ISBN 978-1-920694-74-6.
- ^ "Management of the Houtman Abrolhos" (PDF). Fisheries Management Paper 117. Fisheries WA. 1998. Retrieved 2 May 2008.
- ^ "IBA: Houtman Abrolhos". Birdata. Birds Australia. Archived from the original on 6 July 2011. Retrieved 12 August 2011.
- ^ Department of Environment and Water Resources (2007). Assessment of the Western Rock Lobster Fishery (PDF) (Report). Archived from the original (PDF) on 24 March 2011. Retrieved 4 May 2008.
- ^ David, Greg (2006). Abrolhos Islands Waste Management Coordinator's Report (PDF) (Report). Archived from the original (PDF) on 20 July 2008. Retrieved 4 May 2008.
- ^ a b c Fisheries Western Australia. "Sustainable Tourism Plan for the Houtman Abrolhos islands". Fisheries Management Paper No. 146. Retrieved 23 March 2008.
- ^ "The Houtman Abrolhos Islands Visitors Guide" (PDF). Department of Fisheries, Government of Western Australia. Retrieved 16 August 2009.
- ^ "Appendix 2: Tourist Visitation to the Houtman Abrolhos Islands, 2002-6" (PDF). Archived from the original (PDF) on 29 August 2007. Retrieved 15 November 2007.
External links
- "North Island (Abrolhos), WA – Daily Weather Observations". Bureau of Meteorology, Australia.
- "Abrolhos Islands images, 2002-2004". National Library of Australia catalogue. Retrieved 17 August 2009. — eight photographs from the Houtman Abrolhos, including six from North Island, showing industry and social life of seasonal residents.