Lewis Island (South Australia)

This article is about the island in South Australia. For other uses, see Lewis Island.

Lewis Island

Geography
Location	Spencer Gulf
Coordinates
Country
Australia

Lewis Island is an island located in Spencer Gulf off the east coast of Jussieu Peninsula on Eyre Peninsula in South Australia approximately 29 km (18 mi) south-east of Port Lincoln. It was named by Matthew Flinders in memory of George Lewis who was one of the eight crew lost from a cutter that capsized sometime after being launched from the 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 29 km (18 mi) south-east of Port Lincoln, 926 m (3,038 ft) south of Little Island and 2.8 km (1.7 mi) north of Smith Island. The island has a maximum height of 44 m (144 ft) 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 island’s structure consists of granite outcrop finished with a capping of calcarenite. 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 30 m (98 ft) over a distance of within 100 m (330 ft) on its west, south and east faces.

Flora and fauna

Terrestrial plants

As of 1996, the island was dominated by a shrubland 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 mining 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 geckos, four-toed earless skinks 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 penguins. As of 2007, a breeding population of Australian sea lions 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 Matthew Flinders 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 the HMS Investigator’s cutters 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.

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. It originally obtained protected area status as a fauna reserve under the former Fauna Conservation Act 1964 in 1965. As of December 2012, the waters surrounding the island are in the Thorny Passage Marine Park.