Key Takeaways
- The Mary River cod, an endangered species, has been reintroduced to the Brisbane River catchment in south-east Queensland, 100 years after its close relative, the Brisbane River cod, became extinct in the area.
- The reintroduction is part of a species recovery plan and involves the release of thousands of fingerlings into the catchment.
- The Mary River cod is thriving in the waters, with evidence of spawning and migration to various parts of the river.
- The species plays a crucial role in managing the food web in waterways and helping to mediate pest fish numbers.
- The recovery plan involves collaboration between local councils, fish stocking associations, and state government organisations.
Introduction to the Brisbane River Cod
The Brisbane River catchment, which stretches from Brisbane to Ipswich and the Somerset region, was once home to the Brisbane River cod, a large and apex predator species. However, due to overfishing and habitat destruction, the species became extinct in the 1920s or 1930s. The early settlers of the region knew the fish was easy to catch and was a great source of protein, but they also used it as fodder in piggeries, contributing to its decline. The extinction of the Brisbane River cod led to the loss of a key apex predator in the river, disrupting the balance of the food web.
Habitat Decline and Extinction
The decline of the Brisbane River cod was largely due to habitat destruction, including logging, timber harvesting, and clearing of riparian zones. This destruction led to the loss of habitat and food sources for the species, making it difficult for it to survive. The overfishing of the species also contributed to its decline, as the early settlers took advantage of its abundance and ease of catching. The combination of these factors ultimately led to the extinction of the Brisbane River cod, leaving the river without a key apex predator.
Apex Predator Returns
However, 100 years after the extinction of the Brisbane River cod, its close relative, the Mary River cod, has been reintroduced to the catchment. The Mary River cod is an endangered species, and its reintroduction is part of a species recovery plan. The plan involves the release of thousands of fingerlings into the catchment, as well as the construction of a fish ladder at a weir on the Bremer River, allowing the species to migrate to various parts of the river more easily. The reintroduction of the Mary River cod is a significant step towards restoring the balance of the food web in the river.
Recovery Efforts
The recovery efforts for the Mary River cod are ongoing, with thousands of fingerlings being released into the catchment since 2020. The species is thriving in the waters, with evidence of spawning and migration to various parts of the river. The construction of the fish ladder has also been successful, with a Mary River cod being found using the fishway for the first time in September. The recovery plan involves collaboration between local councils, fish stocking associations, and state government organisations, and is a significant step towards restoring the balance of the food web in the river.
Future Hope
The reintroduction of the Mary River cod has given hope for the species’ recovery, with evidence of spawning and migration to various parts of the river. The species plays a crucial role in managing the food web in waterways and helping to mediate pest fish numbers. The recovery plan is ongoing, with further restoration of riparian habitat planned, which could benefit other animals that call the catchment home, such as platypus. The protection of the Mary River cod is also crucial, with any local fishers who catch one required to release it unharmed. The recovery of the Mary River cod is a significant step towards restoring the balance of the food web in the river and provides hope for the future of the species.
