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Henrietta Rocks
Henrietta Rocks is located on the southeastern coast of Rottnest Island, overlooking Porpoise Bay. The area consists of a sandy beach surrounded by limestone outcrops, rocky reefs and coastal dunes. The surrounding waters contain coral, seagrass beds and a variety of marine life.
The beach is accessible by bus, bicycle or on foot, with the Ngank Yira Bidi walking trail passing nearby. A lookout on the hillside provides views across Porpoise Bay, while the beach and surrounding reefs are popular for swimming, snorkelling and diving.
The origin of the name Henrietta Rocks has not been confirmed. One suggestion is that it was named after Henrietta, a daughter of Sir Gerald Strickland, Governor of Western Australia from 1909 to 1913. Other locations on Rottnest, including Mabel Cove, Mary Cove and Celia Rocks, have also been associated with members of his family.
Early Road Improvements
By October 1933, improvements had been completed to the road leading to Henrietta Rocks, described in a newspaper report as being opposite Dyer Island. Members of a visiting group inspected the completed works, although the extent of the improvements and the original construction date of the road were not recorded.
The Rottnest Sea Monster (1934)
In June 1934, Rottnest Island residents Dan Holt and his son Arthur discovered unusual remains washed ashore near Henrietta Rocks while travelling to a fishing location. They believed the remains belonged to a young whale covered in marine growth.
The discovery attracted public attention in September when Lewis Clayton Timperley, an officer with the Fremantle Customs Department, reported encountering what appeared to be a strange sea creature while walking along the southern coastline with his wife and son.
Timperley estimated that the remains measured approximately 12 feet (3.7 metres) long and weighed around 406 kilograms. They appeared to have several flippers, a rounded head, a curved mouth without visible teeth and a tail resembling that of a kangaroo. The body was covered in what he described as six-inch-long white hair resembling wet wool, while the cream-coloured flesh had a tough, tripe-like appearance.
Ludwig Glauert, curator of the Western Australian Museum, was initially unable to identify the remains from a photograph. He suggested that the apparent covering of hair or wool indicated that the creature was unlikely to be a fish. Reports also indicated that no eyes had been found.
The discovery attracted a busload of visitors from the main settlement, while William Henry Kitson, chairman of the Rottnest Island Board of Control, was among those who inspected the remains.
Further examinations by fisheries officials and museum staff established that the supposed monster consisted of whale remains rather than an unidentified marine creature.
Despite this finding, the remains were transported to Perth, where showman Tasman Bradley exhibited them at the Perth Royal Show in October 1934. The exhibit was eventually disposed of because of its deteriorating condition.
Although Timperley was widely credited with the discovery, a newspaper report published on 22 September 1934 confirmed that the Holt family had encountered the remains approximately three months earlier.
January 2025
The Shark Shipwreck (1939)
Approximately 50 metres offshore from Henrietta Rocks lie the remains of the Shark, a steel hopper barge built at the State Railway Works in 1899 and subsequently operated by the Fremantle Harbour Trust.
On 10 February 1939, the Harbour Trust launch Myrtle departed Fremantle's North Wharf at 6.40 am, towing the Shark towards the ship graveyard off Rottnest Island, where the barge was intended to be sunk.
At approximately 11.30 am, the vessels reached Parker Point, around four miles from their destination. Heavy swells caused the towing line to repeatedly slacken and tighten until it became entangled in the Myrtle's propeller, disabling the launch.
The Shark was cut adrift and subsequently washed onto the reef at Henrietta Rocks, where it remained stranded.
The disabled Myrtle was spotted from Rottnest Island, prompting a request for assistance. G. L. Kennedy, who was holidaying on the island, used his privately owned launch Solstraale to tow the vessel into Thomson Bay.
The Harbour Trust tender Ivanhoe subsequently arrived and took the Myrtle in tow, departing Rottnest at 5.50 pm and reaching Fremantle at 7.55 pm.
As the Shark had already been intended for disposal, no attempt was made to recover it. The wreck remains in shallow water, with sections visible above the surface and provides habitat for marine life.
Some modern visitor information incorrectly states that the barge broke free from its moorings in Fremantle in 1938 and drifted to Rottnest. Contemporary newspaper reports confirm that it became stranded during the towing accident on 10 February 1939.
Fishing at Henrietta Rocks (1955)
By February 1955, Henrietta Rocks was a popular fishing location, particularly for Australian herring. A newspaper article published on 5 February reported that large schools of herring gathered close to shore, attracted by kitchen scraps discarded from Army facilities on Rottnest Island during the mid-morning and mid-afternoon.
The fish gathered in water approximately two to three feet deep, where they were caught by holidaymakers, anglers and off-duty Army personnel. One fisherman reportedly caught 90 herring, while catches of up to five dozen were also recorded.
Despite their numbers, the herring were sometimes difficult to catch because they had already fed on the discarded scraps. Thousands of blowfish and small fish known as trumpeters were also observed.
Coastal Rehabilitation and Beach Access
During the early 2010s, the Rottnest Island Authority undertook coastal rehabilitation and beach access improvements at Henrietta Rocks. Informal walking tracks across the dunes had contributed to erosion, damaged native vegetation and created safety concerns for visitors.
The project included constructing tiered stairs between the roadside lookout and the beach, rehabilitating eroded dunes, replanting native vegetation and installing interpretive signage.
The works were supported by the Winnit Club and the Rottnest Society, with funding through the Coastwest programme. The Rottnest Island Authority's 2011-2012 Annual Report recorded a total project cost of approximately $295,000, including around $141,000 in Coastwest funding. Volunteers from the Winnit Club also assisted with construction.
Vegetation and Conservation
The Master Plan accompanying the Rottnest Island Management Plan 2014-2019 identified a surviving community of rare and threatened plants between Bickley Battery and Henrietta Rocks.
The report described vegetation becoming more diverse with increasing distance from the developed and disturbed areas around Kingstown and Bickley Battery (Master Plan, p. 46; PDF p. 70).
Henrietta Rocks Today
Henrietta Rocks remains a destination for swimming, fishing, snorkelling and diving, particularly around the shallow-water remains of the Shark. The surrounding reefs and seagrass beds provide habitat for marine life.
Visitors can reach the beach using the Island Explorer bus service at Stop 3, while the Ngank Yira Bidi walking trail passes the hillside overlooking Porpoise Bay.
References
Government Reports and Historical Records
Rottnest Island Authority, Annual Report 2011–2012. Coastal rehabilitation and beach access improvements at Henrietta Rocks.
Rottnest Island Authority, Rottnest Island Management Plan 2014–2019, accompanying Master Plan, p. 46 (PDF p. 70). Vegetation and threatened plant communities between Bickley Battery and Henrietta Rocks.
Rottnest Island Authority, Rottnest Island Management Plan 2023–2028, p. 15. Photograph of Henrietta Rocks.
Western Australian Museum, Maritime Archaeology Shipwreck Database, Shark (1899–1939), wreck identification no. 537.
Other Resources
Rottnest Island Authority, Henrietta Rocks visitor information. Beach access, recreational activities, marine environment and the Shark shipwreck.
December 2025
