Nursery production and at sea grow-out of three native kelps from New Zealand: a comparative study
摘要
There has been a limited number of nursery and sea-based cultivation trials for Aotearoa-New Zealand (A-NZ) kelp species. Hence, we investigated the ability of three A-NZ native kelps Lessonia variegata, Macrocystis pyrifera and Ecklonia radiata to grow in aquaculture systems in the country’s largest aquaculture region. The kelps were reared from cultures of gametophytes with the same nursery protocol for two months in the laboratory before being deployed at two aquaculture farms for four months. The results showed strong differences among species in response to the nursery protocol and in terms of their yield (kg m−1) and morphology (sizes of blades, stipes, and holdfasts) when grown at sea. Overall, the giant kelp, M. pyrifera, had the greatest yield (3.2 kg WW m−1), followed by L. variegata (0.3 kg WW m−1) and then E. radiata (0.04 kg WW m−1). The morphology of the kelps varied among sites and depths, especially during the early stages of the experiment. We also quantified the abundance of the invasive kelp, Undaria pinnatifida, which settled naturally during the experiment and had a greater yield (0.75 kg WW m−1) than two of the cultured kelps at one of the sites. We outline the potential for sustainable aquaculture of kelps in A-NZ’s largest aquaculture region addressing knowledge gaps and identifying pathways for technical development to support A-NZ’s emerging seaweed aquaculture sector.