Feasibility of cultivating Ulva lactuca in an Integrated Multi-Trophic Aquaculture system in Big Glory Bay, Stewart Island, New Zealand

Georgia Wilson & Anna Palliser

http://doi.org/10.34074/sitj.17104

Abstract

Ulva lactuca is a species of macroalgae (green seaweed) with a variety of commercial applications such as animal and human nutrition and the creation of bioplastics. In addition, U. lactuca can contribute environmentally by uptaking nitrates produced as waste by aquaculture systems such as salmon farms. In Big Glory Bay (BGB), Stewart Island, New Zealand, U. lactuca could contribute to the development of an integrated multi-trophic aquaculture system (IMTA) with BGB salmon farm. This research explores the viability of growing U. lactuca in the aquaculture zone of BGB by trialling two cultivation methods (vertical and tube net) at the beginning of the winter season. Only vertical cultivation was successful. Growth rates and water quality parameters were measured. By the end of the study growth rates had declined and a high percentage of samples had perished, likely due to falling temperatures and competition from Ectocarpus siliculosus.

Keywords: Aquaculture waste; algae cultivation; nutrients