Introduction
The annual total production of Greenshell™ mussels in New Zealand has remained at around 100,000 tonnes for the past ten years. This industry continues to struggle with improving the efficiency of utilisation of early juvenile mussels or spat, that are used for seeding long-line mussel farms in coastal waters. The losses of mussels between seeding farms with spat and harvesting adult mussels is estimated to exceed 99% for a variety of reasons that have proven difficult to solve with on-farm husbandry. As a result, attention has moved toward using research to develop contained nursery culture of mussel spat to raise them to a larger and more resilient sizes, prior to seeding out onto coastal mussel farms for on-growing to harvest size. However, the nursery culture of mussel spat in containment does not have an international precedent that can be followed, either for mussels or other aquacultured shellfish species. This has led to a multi-pronged research programme aiming to overcome some of the many challenges associated with contained nursery culture of mussel spat, including sourcing spat, feeding, contained nursery culture systems, handling and husbandry. This presentation will outline the problems faced by the Greenshell™ mussels in New Zealand, the breadth of research activity that has resulted, and the progress of the research toward resolving the challenge of developing an effective nursery culture system to improve aquaculture production of this species.