Enhancing Water Quality with Greenshell Mussels
In an innovative collaboration, MacLab has partnered with Cawthron, Port Nelson, and Moananui to enhance water quality in the Nelson Haven by cultivating greenshell mussels (GSM) off one of the port’s wharves.
Port Nelson’s Environment Manager, Shannon Holroyd, noted the success of similar projects at the Ports of Auckland. These projects saw the attachment of 38 seeded mussel lines to public spaces on an inner-city wharf and the reseeding of mussels to improve water quality in the Hauraki Gulf.
As a key partner in the Moananui blue economy cluster, MacLab plays a crucial role in this project. Moananui acts as the national hub for blue economy innovation and high-value creation, fostering collaboration, knowledge exchange, and access to innovation opportunities to accelerate responsible development within the maritime sector.
Together with Port Nelson and Cawthron, we developed the proposal for the Living Filters project, a pioneering six-month trial aimed at introducing GSMs into the port. This project received funding from the Sustainable Seas Fund. MacLab contributed nearly 29,000 juvenile mussels for two frames, which were hung in sleeves off a port wharf in January.
Mark Burnaby, MacLab’s Aquaculture Manager, highlighted the environmental benefits of greenshell mussels. “Greenshell mussels are natural filter feeders,” Burnaby explained. “They improve water quality by removing particles, nutrients, and contaminants from the water, which can help mitigate the effects of urban runoff and industrial pollutants.”
Six weeks into the trial, Shannon reported that the mussels had grown to between 8-11mm. To support this project, Cawthron installed data loggers and samplers to monitor various environmental factors, including water temperature, and the presence of heavy metals and hydrocarbons.
The location, at the estuary of the Maitai River, is known to carry heavy metals from roofs, hydrocarbons, and other urban runoff. Boating activities, such as painting and cleaning ships, also contribute to the presence of these pollutants. Our hope is that the mussels will help reduce these contaminants through their natural filtration process, also known as bioremediation.
Mark Burnaby further noted, “In addition to improving water quality, greenshell mussels can enhance biodiversity by providing habitat for other marine organisms. This can lead to healthier and more resilient marine ecosystems.” See the video below.
