Key Takeaways
- The invasive gold clam, Corbicula fluminea, has been found in Lake Rotomanu in New Plymouth, the first discovery in New Zealand outside the Waikato River.
- The lake will be emptied to allow scientists to assess the extent of the infestation and determine the best course of action.
- The lake will remain empty for the summer, and users are advised to be vigilant and follow the Check, Clean, Dry procedure to prevent the spread of the clam and other freshwater pests.
- A regional coordination group has been established to lead the response to the infestation, and a detailed survey of the lakebed will be conducted to inform the next steps.
- The financial cost of elimination is likely to be significant, and it is unclear how it will be funded.
Introduction to the Invasive Gold Clam
The invasive gold clam, Corbicula fluminea, has been found in Lake Rotomanu in New Plymouth, marking the first discovery in New Zealand outside the Waikato River. This discovery has prompted a swift response from the Taranaki Regional Council, which has closed the lake to motorized watercraft and is now planning to empty the lake to assess the extent of the infestation. The lake’s outlet will be opened on December 11, and it is expected to take around four days for the lake to drain. During this time, the fish population will be harvested in partnership with local hapū, who will utilize as many fish as possible.
Response to the Infestation
The Taranaki Regional Council is leading the response to the infestation, alongside the New Plymouth District Council, Ngāti Te Whiti hapū, Biosecurity New Zealand, Fish & Game, Earth Sciences NZ, and other stakeholders. The Regional Corbicula Coordination Group (RCCG) has been established to coordinate the response and ensure that the clams do not spread to other waterways. Before draining the lake, the RCCG had to ensure that the clams would not spread to the Waiwhakaiho River. Testing and advice on the salinity and flow of the river have provided assurance that any clams or larvae will be quickly washed out to sea.
Survey and Assessment
A team from Earth Sciences NZ will conduct a detailed survey of the lakebed to determine the extent of the infestation, including the location, depth, and age of the clams. This information will inform the next steps in the response, including whether an elimination attempt is feasible and what treatment options are available. The survey will provide valuable insights into the biology and ecology of the clams, which will help to inform the development of an effective management plan. The RCCG will use this information to determine the best course of action, taking into account the potential risks and benefits of different management options.
Implications and Next Steps
The discovery of the invasive gold clam in Lake Rotomanu has significant implications for the region’s waterways and ecosystems. The clams can cause significant economic damage, and their presence can also impact recreational use of the lake. The RCCG is working to prevent the spread of the clams and to minimize the impact on the environment and the community. The financial cost of elimination is likely to be significant, and it is unclear how it will be funded. However, the RCCG is committed to finding a solution and is working with stakeholders to explore options for funding and management.
Prevention and Education
To prevent the spread of the clams and other freshwater pests, lake users are advised to be extra vigilant and follow the Check, Clean, Dry procedure when moving between waterways. This includes checking for any signs of pests, cleaning equipment and gear, and drying it thoroughly before moving to another waterway. A washdown trailer will be set up at popular lakes over the summer, and two dedicated Check, Clean, Dry ambassadors will be in the region to spread the message. New signage, direct education with clubs and organizations, and a social media campaign will also be used to raise awareness and promote best practices.
Conclusion
The discovery of the invasive gold clam in Lake Rotomanu is a significant concern for the region’s waterways and ecosystems. The Taranaki Regional Council and the RCCG are working to respond to the infestation and prevent its spread. The lake will remain empty for the summer, and users are advised to be vigilant and follow best practices to prevent the spread of the clams and other freshwater pests. The RCCG will continue to work with stakeholders to develop an effective management plan and to explore options for funding and management. By working together, it is possible to minimize the impact of the invasive gold clam and protect the region’s waterways and ecosystems.