Lewis Island is an

island An island (or isle) is an isolated piece of habitat that is surrounded by a dramatically different habitat, such as water. Very small islands such as emergent land features on atolls can be called islets, skerries, cays or keys. An island ...

located in

Spencer Gulf The Spencer Gulf is the westernmost and larger of two large inlets (the other being Gulf St Vincent) on the southern coast of Australia, in the state of South Australia, facing the Great Australian Bight. It spans from the Cape Catastrophe and ...

off the east coast of Jussieu Peninsula on

Eyre Peninsula The Eyre Peninsula is a triangular peninsula in South Australia. It is bounded by the Spencer Gulf on the east, the Great Australian Bight on the west, and the Gawler Ranges to the north. Originally called Eyre’s Peninsula, it was named aft ...

South Australia South Australia (commonly abbreviated as SA) is a state in the southern central part of Australia. It covers some of the most arid parts of the country. With a total land area of , it is the fourth-largest of Australia's states and territories ...

approximately south-east of Port Lincoln. It was named by

Matthew Flinders Captain Matthew Flinders (16 March 1774 – 19 July 1814) was a British navigator and cartographer who led the first inshore circumnavigation of mainland Australia, then called New Holland. He is also credited as being the first person to u ...

in memory of George Lewis who was one of the eight crew lost from a cutter that capsized sometime after being launched from HM Sloop ''Investigator'' to search for water on 21 February 1802. Since 2004, the island has been part of the Memory Cove Wilderness Protection Area.

Description

Lewis Island is located approximately south-east of Port Lincoln, south of Little Island and north of Smith Island. The island has a maximum height of above sea level. Access is possible by boat on the island's north east coast during calm weather subject to tidal conditions, particularly in the channel separating it from Little Island.

Formation, geology and oceanography

Lewis Island was formed about 8400 years ago when sea levels rose at the start of the

Holocene The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togethe ...

. The island's structure consists of

granite Granite () is a coarse-grained (phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies undergro ...

outcrop finished with a capping of

calcarenite Calcarenite is a type of limestone that is composed predominantly, more than 50 percent, of detrital (transported) sand-size (0.0625 to 2 mm in diameter), carbonate grains. The grains consist of sand-size grains of either corals, shells, ooi ...

. Unlike the neighbouring islands, the island's cap finishes in a peak at its southern end rather in lieu of a flat plateau. The island rises from the seabed at over a distance of within on its west, south and east faces.

Flora and fauna

Terrestrial plants

As of 1996, the island was dominated by a

shrubland Shrubland, scrubland, scrub, brush, or bush is a plant community characterized by vegetation dominated by shrubs, often also including grasses, herbs, and geophytes. Shrubland may either occur naturally or be the result of human activity. It m ...

of marsh saltbush on its deeper soil. It also supported at least 19 other species including sea celery, karkalla, grey samphire, Australian hollyhock, native juniper, austral stork's bill and pointed twinleaf. Disturbance of the island's surface by

guano Guano (Spanish from qu, wanu) is the accumulated excrement of seabirds or bats. As a manure, guano is a highly effective fertilizer due to the high content of nitrogen, phosphate, and potassium, all key nutrients essential for plant growth. G ...

mining Mining is the extraction of valuable minerals or other geological materials from the Earth, usually from an ore body, lode, vein, seam, reef, or placer deposit. The exploitation of these deposits for raw material is based on the economic via ...

was suggested as the opportunity for weeds, particularly the African box thorn, to spread onto the island.

Terrestrial animals

As of 1996, a breeding colony of white-faced storm petrels was present on the higher southern section of the island. Also, the presence of "relatively high number" of silver gulls and Pacific gulls also suggested the possibility of the island being a breeding site for these species. Black-faced shags were also observed roosting at the island's water line. Reptiles are represented by

marbled gecko ''Christinus'' is a genus of Gekkonidae geckos found in southern regions of Australia. It contains species and subspecies that are regionally termed as marbled geckos. The contrasted patterns of these geckos, marbling, are found in a variety of ...

four-toed earless skink The four-toed earless skink (''Hemiergis peronii''), also known commonly as Péron's earless skink, the lowlands earless skink, or the four-toed mulch skink, is a viviparous earless skink endemic to southern Australia. Etymology The specific ...

s and bull skink. As of 2013, the island is reported as being a breeding site for flesh-footed shearwaters.

Marine animals

As of 1996, observations of burrows immediately below the island's calcarenite capping suggests that it may have supported a colony of

little penguin The little penguin (''Eudyptula minor'') is a species of penguin from New Zealand. They are commonly known as little blue penguins or blue penguins owing to their slate-blue plumage and are also known by their Māori name . The Australian lit ...

s. As of 2007, a breeding population of

Australian sea lion The Australian sea lion (''Neophoca cinerea''), also known as the Australian sea-lion or Australian sealion, is a species of sea lion that is the only endemic pinniped in Australia. It is currently monotypic in the genus ''Neophoca'', with the e ...

s is reported to be present on the island.

History

The island was one of several first sighted by Europeans on Saturday, 20 February 1802, from HMS ''Investigator'' whilst under the command of

entered what is now Spencer Gulf. Flinders named the island on Wednesday, 24 February 1802, in memory of George Lewis who lost his life, presumably drowned, along with seven other members of the crew on Sunday 21 February 1802 when one of HMS ''Investigator’s ''

cutters Cutter may refer to: Tools * Bolt cutter * Box cutter, aka Stanley knife, a form of utility knife * Cigar cutter * Cookie cutter * Glass cutter * Meat cutter * Milling cutter * Paper cutter * Side cutter * Cutter, a type of hydraulic rescue to ...

capsized near Cape Catastrophe.

Economic activity

Gauno

Lewis Island is one of the island sites from which guano was mined under licence from the South Australian Government prior to 1919. It was mined there in the 1880s, and was sold for £3 10s per ton in 1889 by W. R. Cave & Co of

Port Adelaide Port Adelaide is a port-side region of Adelaide, approximately northwest of the Adelaide CBD. It is also the namesake of the City of Port Adelaide Enfield council, a suburb, a federal and state electoral division and is the main port for the ...

Protected areas status

Since 30 September 2004, Lewis Island has been part of the Memory Cove Wilderness Protection Area. Previously, it had been part of the

Lincoln National Park Lincoln National Park is a protected area in the Australian state of South Australia located about west of the state capital of Adelaide and about south of the municipal seat of Port Lincoln. It consists of a mainland area on the Jussieu Pe ...

. It originally obtained

protected area Protected areas or conservation areas are locations which receive protection because of their recognized natural, ecological or cultural values. There are several kinds of protected areas, which vary by level of protection depending on the ena ...

status as a fauna reserve under the former ''Fauna Conservation Act 1964'' in 1965 and gained status as a fauna conservation reserve declared under the ''Crown Lands Act 1929-1966'' on 16 March 1967. As of December 2012, the waters surrounding the island are in the Thorny Passage Marine Park.

References

{{DEFAULTSORT:Lewis Island (South Australia) Islands of South Australia Uninhabited islands of Australia Spencer Gulf