A new nursery approach enhances at-sea performance in the kelp Lessonia corrugata

Abstract

We found that an innovative nursery approach, where Lessonia corrugata seeded spools were cultivated by spinning to increase the water motion relative to non-spinning spools, had higher growth in both the nursery and at-sea stages. Using this method, we compared the at-sea growth of sporophytes cultivated on spinning spools at different depths (1 m, 3 m, 5 m) and seasons (timing of out-planting). Finally, we compared the at-sea growth of sporophytes cultivated on spinning spools vs. non-spinning sporophytes at 3-m depth. In the nursery, sporophytes on spinning spools developed significantly faster than those on non-spinning spools: blade length was 4.6 and 2.5 cm, and holdfast area was 0.10 and 0.03 cm2 for spinning and non-spinning spools, respectively. At-sea L. corrugata in spring had significantly greater biomass production at 3 m and 5 m (3.0 kg m−1 and 2.4 kg m−1, respectively) and up to 96% survival. In summer, 100% of deployed kelps died at all depths. Growth was faster at 5 m (0.3 ± 0.06 kg m−1) in autumn and at 3 and 5 m (1.1 ± 0.1 kg m−1 and 0.8 ± 0.1 kg m−1, respectively) in winter. At sea, sporophytes from the spinning spools grew significantly 60% larger, and survival was ~ 3 times greater over 3 months than sporophytes from non-spinning. Overall, this study shows that spinning seeded spools in the nursery improves the growth at sea, spring is the best season for out-planting L. corrugata, and 3 or 5 m depth is best for production.

Primary production of the kelp Lessonia corrugata varies with season and water motion: Implications for coastal carbon cycling

“…In addition, higher water motion allows for denser natural beds, as the back‐and‐forth movement of the waves can in part compensate for a canopy shading effect and expose the kelps to light (Hurd, Harrison, et al., 2014; Vásquez, 1991; Vásquez et al., 2006). Our study observed a higher density of heavier kelps at Coal Point, where wave exposure was highest, consistent with previous studies on kelp species (Gerard, 1982; Nardelli et al., 2023a; Segovia et al., 2015; Vásquez, 1991; Vásquez et al., 2006). For Lessonia trabeculata in Peru, biomass per m 2 at the more exposed site was nearly double that of the sheltered site, with values of 15.2 kg wet weight · m −2 and 8.3 kg wet weight · m −2 , respectively (Aller‐Rojas et al., 2020).…”

“…This fraction of the global NPP occurs in an area that is <2% of the global ocean surface, which makes this environment highly productive (Duarte, 2017). Kelp forests are particularly productive in temperate regions and areas with permanent upwelling (Krumhansl & Scheibling, 2012; Nardelli, Visch, Farrington, et al., 2023; Yoneshigue & de Oliveira, 1987). This high productivity supports complex ecosystems that rely on these kelps both for food and habitat provision (Bularz et al., 2022; McLachlan, 1985; Pérez‐Matus et al., 2017) and for delivering other crucial ecosystem services, such as carbon storage and cycling (Bennett et al., 2015; Filbee‐Dexter & Wernberg, 2020; Gao et al., 2021; Ramus, 1992).…”

“…The kelp Lessonia corrugata is the only species of the genus Lessonia in the island state of Tasmania, Australia (Asensi & de Reviers, 2009). It predominantly thrives in wave‐exposed and moderately wave‐exposed areas, forming kelp forests all around Tasmania where it supports unique ecosystems with high levels of biodiversity (Hurd et al., 2023; Nardelli, Visch, Farrington, et al., 2023). Interest in this species has grown in recent years, with research focused on a variety of areas, including the genetic structuring of populations (Durrant et al., 2018), tolerance to temperature and irradiance (Dieck, 1993; Paine et al., 2021), nutrient uptake (Smart et al., 2022), commercial aquaculture potential (Visch et al., 2023), and the nutritional composition of cultured biomass (Biancacci et al., 2022).…”