In 1993, the Australian Government declared a nation-wide amnesty calling for members of the public with any historic shipwreck relic or knowledge of an undiscovered historic wreck to report these without fear of prosecution.
As a result, some 20,000 artefacts were declared and about 30 'new' sites reported across Australia. Western Australia received the highest number of artefacts declared. Some of these were donated to the WA Museum while others were retained in private custody.
The WA Museum is responsible for the maintenance of records on this ‘new’ collection, including custody transfer of artefacts between collectors. Cataloguing artefacts held in private custody allows archaeologists to assess what has been removed from sites and improves the scope of information known about the wrecks.
See for related publications:
J.A. Rodrigues. "An Amnesty Assessed. Human impact on shipwreck sites: the Australian case." The International Journal of Nautical Archaeology 38.1 (2009): 153-162.
J.A, Rodrigues. "Evidence in the Private Sphere: Assessing the practicality of amnesties to record lost information." In Archaeologies: Journal of the World Archaeological Congress 5.1, pp. 92-109. USA: Springer, 2009.