In 1997, HMAS Swan was deliberately submerged off the coast of Western Australia. Over five years, scientists studied its evolution into an artificial reef, recording 92 fish species that made the ship their home.In 1997, HMAS Swan was sunk by design off the coast of Western Australia. Once a seagoing warship, HMAS Swan was later turned into an artificial reef in Geographe Bay, where its steel structure now supports a diverse range of marine life. Scientists monitored the wreck over the next five years, and the Department of Conservation and Land Management's monitoring report recorded 92 fish species using the former warship.In the long-term monitoring study, undertaken by the Department of Conservation and Land Management of Western Australia, alterations within the area throughout time since it became submerged were observed. Instead of just conducting one survey, repeat surveys were performed on the wreck from 1998 to 2003 to observe any alterations in fish populations. This study is among the most comprehensive investigations carried out in Australia concerning the marine community of a purposefully sunk warship.The second life of a warship underwaterBefore becoming an artificial reef, the HMAS Swan warship had been in service within the Royal Australian Navy for more than 20 years. After retirement, the ship was cleaned and prepared for its scuttling at Dunsborough.According to the Department of Conservation and Land Management report, the newly submerged ship initially offered little more than hard surfaces. As time passed, those surfaces were colonised by marine organisms, creating conditions that attracted an increasing variety of fish.The monitoring programme found that fish began to use the wreck soon after it was scuttled. With each survey, researchers recorded changes in the mix of species found around the vessel. By the end of the five-year study, a total of 92 fish species had been identified.The report describes reef-associated fish near the structure and species moving through the surrounding waters. Schools of smaller fish were commonly observed around the wreck, while larger predatory species also appeared during surveys.Other researchers highlighted the design of the ship as another explanation for its diversity of fish species. The combination of open decks, vertical surfaces, enclosed rooms and passages resulted in the creation of diverse underwater habitats, giving way to species inhabiting various parts of the wreck.The unique design of the vessel created various habitats, drawing in a rich array of marine life, and the study showcased the lively aquatic community that emerged. Image Credits: Wikimedia CommonsFive-year monitoring revealed a dynamic ecosystemOver the five-year study, the surveys showed that the fish community around HMAS Swan continued to change as the artificial reef matured. Rather than remaining static, the species recorded on and around the wreck varied over time, reflecting the gradual development of the underwater habitat.The study found that the fish community changed throughout the year. According to the monitoring report, some species were recorded only during particular seasons, while others were present more consistently. These patterns reflected natural seasonal changes in the surrounding marine environment.Researchers also observed changes in the number and variety of fish as marine growth became more established on the wreck. The monitoring report indicates that the vessel was used by an increasingly diverse range of species over the course of the study.The report does not describe the wreck as a replacement for natural reefs. Instead, it documents how a carefully prepared vessel became part of the local marine environment and provided habitat for fish and other marine organisms.The findings also highlight the importance of long-term monitoring. A survey conducted soon after the ship was scuttled would have shown only the first stages of marine life settling on the wreck. By continuing observations over five years, researchers were able to document how the fish community changed as the site developed.