Black Swan (dredge)

Work began in 1872,^[4][5] using convict labour,^[4] on the dredging of a path between The Narrows and the William Street jetty, to allow the passage of cargo.^[4][5] This was extended up to Barrack Street, which was the site of King Cole's jetty.^[4][5] The dredge was also used around Fremantle several times, to remove sand banks and to assist boats travelling to the jetty at Pier Street.^[5] Following work on the Perth foreshore reclamation in the 1870s, which used silt from the channels dredged in Perth Water,^[4][5] the vessel was left sitting in the Perth foreshore for several years.^[5]

Following the repairs made in 1887 and 1888, the dredge was officially launched and renamed the Black Swan,^[1][4][5][7] on 19 June 1888.^[1][7] It took its name from the Swan River,^[7] which was named after the black swans living in the area.^[8] The first works done following this involved modifications to the mouth of the Swan River.^[9]

In 1892, the Black Swan was deployed to the Canning River, to cut a channel in the area known as Muddy Reach.^[4][5] Following this job, the dredge was taken back to the Perth Water, where it constructed a channel linking Barrack Street in Perth with Mends Street in South Perth, near the Perth Zoo.^[5] Following this, the Black Swan was used to dredge a channel between Barrack Street and Coode Street, and in 1900 widened the Barrack Street – Mends Street channel. For the next decade the dredge was used on reclamation projects in Perth.

In 1911, the reclamation works in Perth were completed. Subsequently, the equipment used on the project, including the Black Swan was taken out beyond Fremantle Harbour's North Mole and sunk.^[5][6]

Modifications made to the river, including the dredging of shallow Perth Waters, impacted the biodiversity of the Perth area.^[10] River shallows are important for fish breeding grounds, and provided food and shelter for the native black swans,^[10] after which the Swan River was named.^[11] Increasing the depth of the river put much of the swans' aquatic plant food supply out of reach, resulting in loss of habitat.^[10] In 2000, the state government released a plan to combat the decrease in black swan numbers due to dredging and other river modification, through habitat rehabilitation and recreation.^[11]