Table 2 - uploaded by Maeve Edwards
Content may be subject to copyright.
Source publication
Report produced for the BIM 'Aquacutlure Explained' series through the 'Seaweed Hatchery' Project (2008-2011).
Similar publications
Macroepiphytes of Laminaria hyperborea of the Barents and the White Seas were investigated in 2005—2006. The species composition of the epiphytes, their frequency, biomass, cover (%), distri-bution along the host thallus, spatial structure of the epiphyte synusia were studied. 44 species have been recorded on L. hyperborea, and 6 species on its epi...
Biochar has been reported as an efficient tool for carbon sequestration and soil quality improvement, though most research has evaluated the quality of biochar from terrestrial based materials. The study evaluated the macro; micro nutrients and heavy metal concentrations of biochar from seaweeds from Namibian coast. Seaweed species Laminaria pallid...
Shandong and Fujian are two important provinces regarding the development of the seaweed industry, which shared three-fourths of the national seaweed yield in the year 2020. The present study has analyzed the overall situation of the seaweed industry in Shandong and Fujian provinces by comparing annual output, farming area, and species structure. T...
Dansk resumé: I forbindelse med en vurdering af potentialet for produktion af algebiomasse til bioenergi i Danmark blev et dyrkningsprojekt i pilotskala udført. Formålet var at estimere omfanget af arbejdet i forbindelse med og den mulige produktionsstørrelse af makroalger i havbaseret anlaeg i danske farvande. To arter af de store brunalger, finge...
Citations
... crude protein yet had 85% digestibility (Edwards and Watson, 2011). When fed to abalone, crude protein content was 9%-13% DW, and for a juvenile white shrimp (Litopenaeus vannamei) diet, 3.55% protein was added over 28 days and produced a protein efficiency ratio (PER) of 1.7 indicative of weight gain (Indegaard and Minsaas, 1991;Adams, 1994;Federation Food & Drink, 2013;Nelson, 2013). ...
The giant kelp (Macrocystis pyrifera (Linnaeus) C. Agardh 1820) is a habitat-forming brown seaweed in temperate systems with an unexplored potential as a source of seaweed bioproducts. This study used M. pyrifera sporophytes sourced in Tasmania, Australia, to investigate the effect of photoperiod and temperature on growth rates and the nutritional characteristics of the resulting juvenile biomass. Four cultivation treatments combined growth temperatures of 12 °C, 15 °C, 18 °C with light:dark (L:D) of 12:12 and 16:8 (L:D) photoperiods, (12 °C – (12:12); 12 °C – (16:8); 15 °C – (12:12); 18 °C – (12:12) to investigate their effect on the number and size of sporophytes, biomass accumulation and nutritional composition. After 60 days of cultivation the 12 °C – (12:12) treatment had the greatest number of juvenile sporophytes, and the greatest biomass of 14 ± 1.3 g dry weight (DW). The lowest biomass of 1 g DW, was obtained from the 18 °C – (12:12) treatment. The protein content across all treatments ranged from 16-22.48% DW, with the 12 °C (12:12) treatment having largest range, then the 12°C (16:18) treatment was next with 18.48-22.48% DW, and the 15°C (12:12) treatment had the lowest protein range with 16.48-18% DW. These results are in the range of protein content previously reported for brown seaweeds of 5-20%. Total polysaccharide content ranged from 9.6-16.2% DW with the highest content of 16.2% DW obtained for the 15 °C – (12:12) treatment, and the lowest total polysaccharide content of 9.6% DW obtained for the 12 °C (16:18) treatment. After 66 days of cultivation, the highest yield of sulphated polysaccharides of 0.4% DW was obtained for the 12 °C (12:12) treatment. Total fatty acids were analysed, with the highest polyunsaturated fatty acid content of 60.4% detected in the 12 °C (12:12) treatment. This study demonstrates that temperature and photoperiod are factors impacting juvenile sporophyte growth, biomass accumulation and biochemical composition. The study showed the least stressed sporophytes produced the most potentially beneficial nutritional or bioactive profile.
... This washing step was repeated three times. To stimulate zoospore release the sorus was gently dehydrated by wrapping it in paper towel and storing it at 12°C in the dark overnight (Edwards and Watson 2015;Flavin et al. 2013). The sorus was then fully immersed in 4°C filtered seawater (0.2 μm) for 1 h to release zoospores. ...
Kelp aquaculture is an emerging industry outside of Asia. To be successful, this industry requires a reliable production of seedstock, the optimisation of which greatly benefits from a detailed physiological understanding of the microscopic life-cycle stages of the cultured species. This study investigated the impact of six zoospore densities (10–278 mm ⁻² ) on the subsequent development of Ecklonia radiata gametophytes and sporophytes. The results showed that germination rates and sex ratio were unaffected by initial zoospore density, but there were significant effects on gametophyte size and sporophyte production. After two weeks, female gametophytes were largest at an initial zoospore density of 40 mm ⁻² while male gametophytes grew largest at densities below 40 mm ⁻² , but after four weeks gametophyte size showed a negative relationship with initial zoospore density. Significantly more sporophytes developed at initial zoospore densities below 40 individuals mm ⁻² and no sporophytes were observed at the highest density (271 zoospores mm ⁻² ). These results clearly show the importance of initial zoospore density in optimising the nursery stage of kelp aquaculture.
... Firstly, water motion by gentle aeration is likely to improve gametogenesis and the transition to sporophytes as demonstrated for Lessonia trabeculata (Tala et al. 2004), Pterygophora californica and M. pyrifera (Reed et al. 1991). Moreover, aeration is commonly used during the hatchery stage of kelps (Edwards and Watson 2011;Redmond et al. 2014;Rolin et al. 2014) as water movement increases the nutrient uptake (Barr et al. 2008), resulting in improved growth of sporophytes (Yoneshigue-Valentin 1990). Secondly, lower nutrient concentrations might improve the transition rates as high concentrations of nitrogen have been shown to inhibit the transition (Yarish et al. 1990;Boderskov et al. 2022). ...
The kelp Ecklonia radiata has become a target for controlled cultivation. However, to date there are no standardised protocols for the hatchery stage of this species that result in high rates of germination, gametophyte development and transition to sporophytes. Therefore, the objective of this study was to quantify the effect of photoperiod, light intensity, temperature, nutrient media and use of GeO2 on the key hatchery processes of germination, gametophyte development and transition to sporophytes in controlled laboratory experiments. Germination of E. radiata was high (≥ 85%) throughout the study, regardless of treatments. Temperature had a major effect on the length of gametophytes, which increased with increasing temperature. The formation of sporophytes was favoured when individuals were maintained under 17 °C continuously, while reduced by approximately 30% when using F/2 compared to PES nutrient media. Overall, the recommended conditions for the hatchery stage of E. radiata are to maintain cultures under a 12 h L:12 h D photoperiod at 17 °C as this resulted in higher germination rates, good gametophyte development and higher transition to sporophytes compared to other treatments. Moreover, the use of GeO2 has to be limited to no more than 2 days as extended use has detrimental effects on the development of sporophytes. Finally, storage of sorus-bearing fronds of sporophytes up to 4 days after the collection from the field generally increased the number of released zoospores and is a simple mechanism to increase the fertility of brood stock.
... Nurseries require a laboratory grade facility, a consistent supply of filtered and sometimes sterilized seawater, centralized pumps and plumbing, grow-lights, blowers for aeration, nutrients, and skilled labor (Edwards and Watson, 2015). Nurseries usually supply 1 -2 mm diameter twine (made of natural or synthetic fibers) wrapped around PVC pipes (hereafter referred to as "spools"; Figure S1A) and seeded with juvenile sporophytes. ...
Aquaculture of seaweeds, particularly in emerging farming regions such as North America, Europe, and South America, is steadily increasing. The growth of the sector has been supported by public and private R&D investment with the long-term goal of reducing farm-gate production costs. Reducing expenses would potentially allow growers to target high volume, low value markets, such as hydrocolloids, animal feeds, food thickening agents, biofuels, and carbon dioxide removal (CDR), as well as the higher value, “whole foods” markets. Regardless of the eventual fate of farmed seaweed, nursery production must increase in parallel with ocean cultivation to support the raw materials needs of the expanding industry. We quantified S. latissima (hereafter kelp) nursery production costs and identified potential barriers to cost-effective scaling using a techno-economic model (TEM). Semi-structured interviews with nursery operators in the U.S. and Europe were supplemented by an extensive literature review to parameterize the TEM. Reducing the sporophyte grow-out duration, increasing labor capacity, de-risking energy efficient flow-through systems, and optimizing tank and PVC “spool” size emerged as the most important research priorities based on our analysis. We point towards expanded gametophyte culture, and an associated policy framework to protect wild kelp population structure from monocultures, as necessary elements to support these potential improvements. The results of this work, as well as the open-source nursery TEM, are relevant to seaweed aquaculture producers, policy makers, and researchers, and can be used to guide future decision making regarding the cost-benefit of best available nursery technology.
... Zoospores or young sporophytes can be seeded on collectors or on ropes directly. While collectors usually stay in the hatchery for up to two months until the young sporophytes reach a size of 1-5 cm and are transferred to long lines in the open sea, direct seeded ropes can be deployed within days after seeding (Pereira and Yarish, 2008;Edwards and Watson, 2011;Rolin et al., 2016). ...
The sugar kelp Saccharina latissima is cultivated in Europe for food, feed and ultimately the production of chemical commodities and bioenergy. Being cultivated in the open sea, S. latissima is exposed to potentially harmful organisms, such as Laminarionema elsbetiae, a filamentous brown algal endophyte with a very high prevalence in wild populations of European S. latissima. As it was shown previously that S. latissima sporophytes get infected by L. elsbetiae very early in their life, seeding the spores on collectors and keeping them under controlled conditions during the critical time of a possible infection with filamentous endophytes could be advantageous over direct seeding techniques, where the ropes are deployed within days after seeding. We used a qPCR-assay to assess the prevalence of the endophyte L. elsbetiae in S. latissima cultivated during winter in Northern Brittany, comparing individuals from direct-seeded ropes and collector-seeded lines that were kept in laboratory conditions for different time spans. No DNA of the endophyte was detected in the samples, suggesting that either the kelps were not infected or the amount of endophytic filaments were below the detection rate of the qPCR assay. Furthermore, L. elsbetiae could not be detected in the seawater surrounding the kelp farm, indicating that L. elsbetiae is not fertile or disperses at a very small scale in Northern Brittany during the deployment time of young kelps. Our results suggest that infections of cultivated S. latissima with the endophyte L. elsbetiae might be a minor problem in kelp farms in Northern Brittany if the seeding production is kept under controlled conditions without external contamination.
... From an economic perspective, any renewable technology must be economically viable and benefit the region in which it is situated (Gegg and Wells, 2017). In the commercial context of fuels, this viability depends on where and how the fuel is produced (Edwards and Watson, 2011;Nigham and Singh, 2011), seaweed prices (Neish, 2013;Hermannsson and Swales, 2015), and inshore cultivation is favoured (Hughes et al., 2013). In Asia, seaweed farming has benefited coastal communities by supporting farming and supply-chain employment due to its labour-intensive nature (Netalgae, 2012;Krishnan and Narayanakumar, 2013;Hermannsson and Swales, 2015;Fernand et al., 2017). ...
Macroalgae (seaweed)-derived fuels are gaining increasing attention due to the high rate of seaweed growth, its lack of lignocellulose (which makes for energy-efficient processing), its lack of need for land or freshwater, and its potential suitability for commercial applications in the UK. However, while technological issues are progressively being solved, wider issues of stakeholder and public perception have largely been ignored, potentially hindering the development of this technology. This research fills this gap by conducting 19 interviews with stakeholders and 7 focus groups with members of the public to gain a deeper and broader understanding of perceptions of macroalgae-derived fuels. The results highlight the technological promise and confidence in the potential of macroalgae-derived fuels. However, they also emphasise conflicts and uncertainties among stakeholders (e.g. competition with other high-value products derived from macroalgae) and the general public (e.g. conflict with marine users). This paper provides insight into potential social resistance and key issues in the macroalgae-to-fuels supply chain. This information will enable two-way communication between everyone involved and increase the likelihood of successfully developing this supply chain. Key policy issues are discussed to facilitate this communication and encourage investment in the process.
... Brown kelp species Laminaria digitata and Saccharina latissima are commonly found in Northern Europe and have attracted attention as a carbohydrate rich feedstock for the production of bioenergy and biochemicals. The industrial cultivation of Laminaria digitata currently involves reproduction and culture development under laboratory conditions, before deployment at sea over 6e7 months and subsequent harvesting (Edwards and Watson, 2011). This yields approx. ...
... 7e8 kg dry weight m À1 . Using a 30 m  30 m grid system with 6 grids per hectare, this leads to an overall yield of 18.9 tonnes of seaweed per hectare (Edwards and Watson, 2011). An alternative ring design for offshore cultivation is described by Buck and Buchholz (2004). ...
... This can be contrasted with a previous Dutch study which estimates cost per tonne (dry weight) at between $155 and $564 (Reith et al., 2005). A more recent Irish study put the breakeven cost of production at between V1120 and V2150, with the lower value based on co-production within a scallop hatchery and mussel farm (Edwards and Watson, 2011). van den Burg et al. (2016) reviewed economic feasibility of seaweed cultivation within the North Sea. ...
Marine macroalgae (seaweed) has many advantages over terrestrial crops as a source of renewable biomass but is severely underutilised at present, especially within Europe. In particular, macroalgae has elevated poly- and monosaccharide content, making it an ideal feedstock as a heterotrophic fermentation sugar source for the production of higher value chemicals. Recent reports have detailed the suitability of seaweeds as a feedstock for the production of single-cell oils (SCOs) which have application in food, oleochemicals and fuels. It is proposed that a biorefinery system based on the production of SCOs alongside other secondary metabolites, has the potential to provide a sustainable replacement to terrestrial oils such as palm oil.
This work therefore evaluates, for the first time, the environmental and economic sustainability of a production process for SCOs from seaweed Saccharina latissima using the oleaginous yeast Metschnikowia pulcherrima. Two alternative fermentation systems were considered, and uncertainties associated with the seasonal variation in seaweed carbohydrate yield and fermentation performance were integrated into the analysis. From an environmental perspective, the work indicates that seaweed derived SCO lipids and fats can be comparable to a terrestrial oil mix, with a potential climate change impact ranging between 2.5 and 9.9 kg CO2 eq. kg⁻¹ refined SCO. Interestingly and of particular significance, environmental impacts are mainly dominated by energy demand within fermentation and upstream processing steps. From an economic perspective, a break-even selling price for the oil was determined as between €5,300-€31,000 tonne⁻¹ refined SCO, which was highly dependent on cost of the seaweed feedstock.
Overall, we demonstrate that key uncertainties relating to seaweed cultivation costs and hydrolysate fermentation at scale result in a large range in values for environmental impact and economic return on investment. Yet even within the constraints and limitations of current knowhow, seaweed already offers a viable proposition for the competitive production of exotic oils similar to cocoa or shea butter in price and nature.
... Currently, 86% of kelp are cultured in China, mostly the species Saccharina japonica and Undaria pinnatifida [39]. However, kelp aquaculture is expanding globally [35], such as with Saccharina and Laminaria spp. in Europe [40,41] and Macrocystis pyrifera in Chile [42]. ...
Two sister orders of the brown macroalgae (class Phaeophyceae), the morphologically complex Laminariales (commonly referred to as kelp) and the morphologically simple Ectocarpales are natural hosts for the dsDNA phaeoviruses (family Phycodnaviridae) that persist as proviruses in the genomes of their hosts. We have previously shown that the major capsid protein (MCP) and DNA polymerase concatenated gene phylogeny splits phaeoviruses into two subgroups, A and B (both infecting Ectocarpales), while MCP-based phylogeny suggests that the kelp phaeoviruses form a distinct third subgroup C. Here we used MCP to better understand the host range of phaeoviruses by screening a further 96 and 909 samples representing 11 and 3 species of kelp and Ectocarpales, respectively. Sporophyte kelp samples were collected from their various natural coastal habitats spanning five continents: Africa, Asia, Australia, Europe, and South America. Our phylogenetic analyses showed that while most of the kelp phaeoviruses, including one from Macrocystis pyrifera, belonged to the previously designated subgroup C, new lineages of Phaeovirus in 3 kelp species, Ecklonia maxima, Ecklonia radiata, Undaria pinnatifida, grouped instead with subgroup A. In addition, we observed a prevalence of 26% and 63% in kelp and Ectocarpales, respectively. Although not common, multiple phaeoviral infections per individual were observed, with the Ectocarpales having both intra-and inter-subgroup phaeoviral infections. Only intra-subgroup phaeoviral infections were observed in kelp. Furthermore, prevalence of phaeoviral infections within the Ectocarpales is also linked to their exposure to waves. We conclude that phaeoviral infection is a widely occurring phenomenon in both lineages, and that phaeoviruses have diversified with their hosts at least since the divergence of the Laminariales and Ectocarpales.
... Kelp Aquaculture Production Model: There are no commercial kelp farms or kelp farm proposals in California, and thus our model of kelp aquaculture in Southern California is based on extrapolations from best estimates in the literature and from kelp aquaculture operations elsewhere. Most of our information on practices and design of kelp farms was informed by the kelp aquaculture industry 20 and a report issued by Irish Sea Fisheries Board on development and demonstration of seaweed aquaculture methodologies 21 . We parameterized our model based on the brown algae (kelp) Saccharina latissima, also known as Laminaria saccharina. ...
... Hatchery costs: We approximated the start-up seed and hatchery costs based on the best available information. The Irish Sea Fisheries Board estimates the cost of setting up a hatchery to be $45,000 21 . This value was converted to US dollars at the rate of 1.43 dollars/Euro, which was the exchange rate in May of 2011 when the report was published. ...
... We changed the yearly operational costs of the hatchery (included in fixed operating costs) to reflect the different hatchery process required for kelp. Costs were based on the Irish Sea Fisheries report, which estimates hatchery costs to be $130,871 annually 21 . We multiplied this cost by three (since our farm design is producing approximately three times the production of the Irish farm) to estimate the annual cost of a kelp hatchery. ...
... The cultivation methods used in this work were based on standard procedures (e.g. Edwards and Watson 2011). Fertile individuals of Saccharina latissima were collected by divers in Oyragjógv, Faroe Islands, on 9 January 2015. ...
... deviation n = 3 except for the 29th of April when n = 1 a Amino acids are essential in human nutrition J Appl Phycol (2017) 29:2277-2286 sporophyte culture was sprayed directly onto the droplines right before deployment, skipping space and time of the demanding hatchery phase (from spore unit to germinating sporophyte on collectors or ropes), and the entwining process of the collectors around the dropline (e.g. Edwards and Watson 2011;Handå et al. 2013). We carried out the entire hatchery development from spore to juvenile sporophytes in culture flasks saving the space in the hatchery that the collectors or ropes would otherwise have demanded. ...
Ropes seeded directly with Saccharina latissima were deployed at different exposures (sheltered, current exposed and wave exposed) in a Faroese sound and characteristics of growth and quality of the biomass and surroundings were evaluated during the growth season from March to August 2015. Saccharina latissima individuals cultivated at the current exposed location were heavier compared to the individuals cultivated at the other locations; however, the total biomass yield was significantly lower at the current exposed location. The protein and nutritional value of the biomass varied with season but showed no correlation with exposure. The highest protein levels and EAA (essential amino acid) score were measured in the spring (April and May) samples. The amino acid composition was dominated by glutamate followed by aspartic acid; however, this was replaced by me-thionine in the July samples. Total Kjeldahl nitrogen was significantly higher in May and August compared to July, and the nitrate concentration in the biomass was significantly lower in May and August compared to July. Nitrate was most available in the seawater at the time of deployment (3rd of March) and decreased during spring and summer. Saccharina latissima was cultivated successfully at the sheltered, current exposed and wave exposed locations using a direct seeding method. However, our results indicate that the lower biomass yield at the current exposed cultivation location compared to the sheltered and wave exposed are due to the direct seeding method, and possible limitations using this method need further testing and optimization.
