I am being funded by a FRST Tuapapa Putaiao Maori Fellowship. My study is focused on the management of food depletion inside mussel farms in the Marlborough Sounds. Marine aquaculture in New Zealand has shown a rapid expansion, and continues to grow at a rapid rate. Farming of the mussel Perna canaliculus is the largest sector of the marine aquaculture industry. Considerable concern has been expressed over whether present levels of production are close to carrying capacity.
Cultured mussels rely on an adequate supply of natural food, primarily phytoplankton.
Phytoplankton productivity is itself dependent on the supply of nutrients, particularly nitrogen. The primary objective of this project is to gain essential biological data by monitoring ambient nitrogen concentration and by assessing the grazing impact of mussel farms on ambient phytoplankton abundance over time. Ambient nitrogen abundance is highest during winter months. By September, nitrate concentrations are at low levels, and tend to stay low through summer. The ambient phytoplankton concentrations show a similar pattern to nitrogen.