Development of Saccharina latissima (Phaeophyceae) kelp hatcheries with year-round production of zoospores and juvenile sporophytes on culture ropes for kelp aquaculture

Abstract

Saccharina latissima is attractive for industrial cultivation for different usages, such as biofuels, feed supplements, and derivation of chemicals. A continuous supply of kelp sporelings throughout the year may ensure a yearround production of kelp juveniles on ropes. In this study, induction of sporangial areas (sorus portions) on the blade of S. latissima was performed throughout the year at three locations: Trondheim (Norway), Grenaa (Denmark), and Sylt island (Germany). The results indicate that a yearround sorus induction in S. latissima is possible and that this induction is controlled by applying short-day treatment of adult sporophytes throughout the year and by the removal of the basal blade meristem. The artificially induced and released zoospores formed viable sporelings at all seasons, but cultivation in the sea in Norway was successful only during autumn, winter, and spring, while the growth conditions were poor during the summer. The results are important for industrial scale-up and continuous production of kelp biomass.

Seaweed aquaculture in Norway: recent industrial developments and future perspectives

“…Although the production of spores in natural kelp populations is seasonal and species-specific (Bartsch et al 2008), sorus (reproductive structure) formation can be induced artificially by, for example, controlling the light regimes provided to adult sporophytes. In this way, viable sporelings can be produced at all seasons (Forbord et al 2012). However, biofouling of the biomass from epiphytic organisms limits the cultivation period at sea from autumn to spring (see Risk assessment 1-epiphytes and diseases).…”

“…In Norway, the presence of epiphytic invertebrates, especially bryozoans (e.g. Membranipora membranacea and Electra pilosa), but also blue mussels (Mytilus edulis), hydroids and fouling macroalgae has been reported for sugar kelp cultivated at sea during summer months (Forbord et al 2012;Handå et al 2013;Lüning and Mortensen 2015;Førde et al 2016). In worst case scenarios, such fouling may lead to extensive blade damage and loss of biomass or considerable quality deterioration.…”

“…In worst case scenarios, such fouling may lead to extensive blade damage and loss of biomass or considerable quality deterioration. Whereas, the diversity of associated organisms in natural kelps beds carries important ecological functions in coastal areas (Christie et al 2009), biofouling by epiphytes is a major constraint for the year-round cultivation of seaweed biomass, forcing producers to harvest in May-June, hence limiting the year-round seaweed cultivation at sea (Forbord et al 2012;Peteiro and Freire 2013;Førde et al 2016). Outbreaks of encrusting colonies of the bryozoan M. membranacea are the result of settlement of cyphonaut larvae, which are present in the water column of coastal area throughout the year (Ryland 1965;Saier and Chapman 2004) with a peak of abundance during the summer (Ryland 1965;Førde et al 2016).…”

Modelling the cultivation and bioremediation potential of the kelp Saccharina latissima in close proximity to an exposed salmon farm in Norway

“…Saccharina latissima cultures, prepared according to Forbord et al (2012), were deployed at 2 stations, 1 close to the fish farm (FF) and 1 at a reference station (RS) about 4 km south of the farm (Fig. 1B), on 19 August 2010 and 21 February 2011.…”

“…The values were chosen so that the simulated frond size in creased from 0.2 to 3.55 cm 2 from 19 August to 16 September at the FF location (Table 2). At deployment, sporophytes were 5 to 10 mm long (Forbord et al 2012).…”