Allyson E. Nardelli1*, Wouter Visch1, Glenn Farrington1, J. Craig Sanderson3, Alecia Bellgrove2, Jeff Wright1, Catriona L. Hurd1.
1Institute for Marine and Antarctic Studies (IMAS), 20 Castray Esplanade, Battery Point, 7004, TAS, Australia
2 Deakin University, School of Life and Environmental Sciences, Centre for Integrative Ecology, Warrnambool Campus, Warrnambool, Victoria 3280, Australia
3 Tassal Pty Ltd, 1/5 Franklin Wharf, Hobart TAS 7000, Australia
Kelp farming is increasing in temperate regions globally, requiring knowledge of seasonal growth, alongside the development of approaches to improve sustainable kelp farming. Here, we studied the at-sea cultivation of Lessonia corrugata at different depths (1 m, 3 m, 5 m) and seasons. We also tested an innovative new nursery approach, where seeded spools were cultivated by spinning (SS) (relative to a control: not spinning (SN)) to increase the water motion and light homogeneity across seeded spools. In spring, L. corrugata had faster growth at 3 m and 5 m (8 ± 1.2 mm·day-1 and 7.5 ± 1.5 mm·day-1, respectively) and up to 96% higher survival than in other seasons. In summer, 100% of kelps died at all depths. In autumn, L. corrugata had faster growth at 5 m (3.1 ± 1.8 mm·day-1) and up to 42% survival, and a similar result was found in winter. In the nursery, sporophytes on SS seeded spools had a quicker development when compared with NS spools: blade size was 42 ± 8 mm and 25 ± 4 mm, and holdfast area was 0.1 ± 0.9 cm2 and 0.03 ± 0.01 cm2 for SS and NS, respectively. The spools were subsequently deployed at sea, and SS grew 60% more, and survival was 12% higher than for SN. We conclude that spring is the best season to deploy L. corrugata at sea at depths between 3 and 5 m and that spinning the seeded spools is a promising method to improve cultivation of L. corrugata.