Intensive cultivation of freshwater macroalgae is likely to increase with the development of an algal biofuels industry and algal bioremediation. However, target freshwater macroalgae species suitable for large-scale intensive cultivation have not yet been identified. Therefore, as a first step to identifying target species, we compared the productivity, growth and biochemical composition of three species representative of key freshwater macroalgae genera across a range of cultivation conditions. We then selected a primary target species and assessed its competitive ability against other species over a range of stocking densities. Oedogonium had the highest productivity (8.0 g ash free dry weight m22 day21 ), lowest ash content (3–8%), lowest water content (fresh weigh: dry weight ratio of 3.4), highest carbon content (45%) and highest bioenergy potential (higher heating value 20 MJ/kg) compared to Cladophora and Spirogyra. The higher productivity of Oedogonium relative to Cladophora and Spirogyra was consistent when algae were cultured with and without the addition of CO2 across three aeration treatments. Therefore, Oedogonium was selected as our primary target species. The competitive ability of Oedogonium was assessed by growing it in bi-cultures and polycultures with Cladophora and Spirogyra over a range of stocking densities. Cultures were initially stocked with equal proportions of each species, but after three weeks of growth the proportion of Oedogonium had increased to at least 96% (67 S.E.) in Oedogonium-Spirogyra bi-cultures, 86% (616 S.E.) in Oedogonium-Cladophora bi-cultures and 82% (618 S.E.) in polycultures. The high productivity, bioenergy potential and competitive dominance of Oedogonium make this species an ideal freshwater macroalgal target for large-scale production and a valuable biomass source for bioenergy applications. These results demons
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Sandfish (Holothuria scabra) hatchery production is currently being done at various scales across several continents including Australia, Maldives, Vietnam, Pacific island countries, Madagascar and the Philippines. Work in Mindanao in the southern Philippines, through the University of the Philippines Mindanao (UPMin), commenced in 2006. UPMin set up experimental hatcheries, ponds and other facilities by establishing partnerships with two local corporations: Alsons Corporation and JV Ayala Group of Companies. The former facility also has a seawater channel feeding fish ponds, which, through time, has harboured resident populations of sandfish. This channel became a source of broodstock, as well as a ‘conditioning area’ for sandfish collected from the wild. It also served as the first-stage nursery for juveniles. This paper describes low-cost technology for all stages of culturing H. scabra up to production of juveniles ≥10 g for release, and compares the cost-cutting innovations with those of published protocols. Three local modifications made by the UPMin project team are described here: the use of a seawater channel for broodstock and hapa; mono-algal feeding using Chaetoceros calcitrans; and the use of recycled or locally made materials. Broodstock can be kept for weeks in the channel with zero mortality, even without maintenance. In the hapas, juveniles can grow to 5–10 g in 1–2 months at an average survival of 84%. Chaetoceros calcitrans was bought from Alsons and scaled up using recycled 250-L PVC barrels. It was used as a feed until the early juvenile stage. These innovations yielded a best performance average of 2.2% survival to 3–5-mm juveniles. This paper attests to the progress and innovations made in sea cucumber research in the Philippines since H. scabra production was pilot-tested in the country in 2002.
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Carrageenan seaweed farming based primarily on the cultivation of Kappaphycus and Eucheuma species has grown significantly in the Philippines and Indonesia in the last two decades. Growth has also taken place on a smaller scale in the United Republic of Tanzania and a few other developing countries. Thanks to attributes such as relatively simple farming techniques, low requirements of capital and material inputs, and short production cycles, carrageenan seaweed farming has become a favourable livelihood source for smallholder farmers or fishers and generated substantial socio-economic benefits to marginalized coastal communities in developing countries. However, further development of carrageenan seaweed farming needs to overcome various barriers and constraints such as inclement weather conditions, disease outbreaks, uncertain and fluctuating market conditions, lack of value-added products and value-adding activities in most of seaweed farming countries, low incomes of seaweed farmers in some countries, and occupational health hazards. With six country case studies and one global synthesis, this document attempts to provide a balanced assessment and comparison of the social and economic performance of carrageenan seaweed farming in different countries. Various issues related to seaweed–carrageenan value chains are highlighted. The technical and economic performance of a number of carrageenan seaweed farming cases are systematically evaluated and compared. The positive and negative social impacts of carrageenan seaweed farming are discussed. Issues related to governance and institutions in the sector are reviewed. Challenges and constraints faced by different countries in the future development of their seaweed industries are identified. The document also highlights a series of information and knowledge gaps that need to be filled in order to form a clearer vision of carrageenan seaweed farming development in the future and facilitate evidence-based policy decision-making and sector management.
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The Ramanathapuram district in Tamil Nadu was identified as the target location for studying the structure, conduct and performance of seaweed farming in India in view of its historical background, locational advantages, industry interactions, socio-economic institutional framework and opportunities for expansion and growth. For these reasons, the Ramanathapuram district has long been recognized as the center of the seaweed farming in India. Although 434 species of red seaweeds, 194 species of brown seaweeds and 216 species of green seaweeds naturally occur in India, it was only until the beginning of the twenty-first century that the country made any concrete progress towards organized seaweed farming. The tardy progress was caused by a number of factors including locational disadvantages, inconsistent performance of species for commercial exploitation, absence of a complete package of farming practices, and industry and policy support. Although the commercial potential of Kappaphycus alvarezii had been previously recognized and its culture technology had been perfected by the Central Salt and Marine Chemicals Research Institute (CSMCRI), culture at a commercial scale only began when PepsiCo India Holdings Ltd (PepsiCo) made its entry into the venture with a pilot-scale investment in the early 2000s. The entry of PepsiCo turned out to be decisive, acting as a catalyst to rejevunate the industry-institutional linkages.
The concept of Self Help Groups (SHG) spearheaded by the National Bank for Agricultural and Rural Development (NABARD) also led to rapid development in the Mandapam area of Ramanathapuram, which soon became the hub of seaweed farming in the country. Self Help Groups in the fishing villages of Vedalai, Thonithurai, Ariyankkundu and R. Vadakadu currently operate more than 1,000 rafts. Many of the SHGs have been able to obtain a yield of more than 50 kg per raft per day (dry weight). Based on findings from this study, seaweed farming offered 161 and 144 days of employment per annum in the Rameshwaram and Mandapam areas, respectively. With current development projections targeting 5,000 families in the near future, the seaweed sector could generate around 765 thousand man-days of employment in the Ramanathapuram district. It has been estimated that India can produce one million tonnes of x dried seaweed and provide employment to 200 thousand families with annual earnings of around ` 0.1 million per family. The annual turnover of Kappaphycus seaweed farming alone can be safely estimated to be ` 2.0 billion.
Spearheaded by private investments, the clear institutional and financial support of the Government of India through development agencies and research establishments has been fundamental for the development of the sector. The distinct possibility of expansion of operations based on successful commercial trials in sites in Andhra Pradesh and Gujarat will give a significant boost to the sector. Seaweed farming has all the potential to rise from a low-income livelihood activity into a reasonably profitable commercial enterprise in coastal India.
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Some observations made on the output and viability of oospores in Sargassum wightii are presented. iMiaximum output of healthy spores was observed for seven days in the laboratory experiments, without any periodicity in the Eberation of oospores. Spore-shedding season extends for three months, from November to January, with the highest value in December. In viability experiments 47.6% of the sporelings have been found in healthy condition at the end of 60 days.
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To find a disinfecting method that relieves sori from diatom contamination, without damaging the spores or affecting the early development of young sporophytes.
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The green seaweed Ulva is one of South Africa’s most important aquaculture products, constituting an important feed source particularly for abalone (Haliotis midae L.), and utilized as a bioremediation tool and other benefits such as biomass for biofuel production and for integrated aquaculture. Besides Ulva spp, Gracilaria spp. are also cultivated. Wild seaweed harvest in South Africa totals 7,602 mt, compared to 2,015 mt of cultivated Ulva. To mitigate for the reliance on wild harvesting, the South African seaweed aquaculture industry has grown rapidly over the past few decades. On-land integrated culture units, with paddle-wheel raceways, are now widely viewed as the preferred method of production for the industry. The success of seaweed aquaculture in South Africa is due to a number of natural and human (industrial) factors. The development of the seaweed aquaculture industry has paralleled the growth of the abalone industry, and has been successful largely because of bilateral technology transfer and innovation between commercial abalone farms and research institutions. In South Africa seaweeds have been used commercially as feedstock for phycocolloid production, for the production of abalone feed, and the production of Kelpak® and Afrikelp®, which are plant-growth stimulants used in the agricultural sector. Additionally, Ulva is being investigated for large-scale biogas production. The South African seaweed industry provides a template that could be used by other coastal African nations to further their undeveloped aquaculture potential.
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Concerns about how ocean acidification will impact marine organisms have steadily increased in recent years, but there is a lack of knowledge on the responses of macroalgae. Here, we adopt an outdoor continuous-flowing mesocosm system designed for ocean acidification experiment that allows high CO2 conditions to vary with natural fluctuations in the environment. Following the establishment of the mesocosm, five species of macroalgae that are common along the coast of Korea (namely Ulva pertusa, Codium fragile, Sargassum thunbergii, S. horneri, and Prionitis cornea) were exposed to three different CO2 concentrations: ambient (×1) and elevated CO2 (2× and 4× ambient), over two-week period, and their ecophysiological traits were measured. Results indicated that both photosynthesis and growth exhibited species-specific responses to the different CO2 concentrations. Most notably, photosynthesis and growth increased in S.thunbergii when exposed to elevated CO2 conditions but decreased in P. cornea. The preference for different inorganic carbon species (CO2 and HCO3-), which were estimated by gross photosynthesis in the presence and absence of the external carbonic anhydrase (eCA) inhibitor acetazolamide, were also found to vary among species and CO2 treatments. Specifically, the two Sargassum species exhibited decreased eCA inhibition of photosynthesis with increased growth when exposed to high CO2 conditions. In contrast, growth of U. pertusa and C. fragile were not notably affected by increased CO2. Together, these results suggest that the five species of macroalgae may respond differently to changes in ocean acidity, with species-specific responses based on their differentiated photosynthetic acclimation. Understanding these physiological changes might allow us to better predict future changes in macroalgal communities in a more acidic ocean.
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Forty percent of the population in India is estimated to be vegetarian. Seaweeds with its high nutritive value constitute a potential resource of valuable supplementary food. India has a coastline of 5 698 km. Rocky and coral formations are found in Tamil Nadu, Grujarat states, and in the vicinities of Bombay, Karawar, Batnagiri, Goa, Vizhinjam, Varkala, Vishakapatnam, and in few other places like Chilka and Pulicat lakes, Andaman and Nicobar Islands. The coastal areas of Tamil Nadu and Grujarat states are the important seaweed growing regions of the country.
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Indonesia needs at least 1,100 tons of alginate per year for various food and non-food industries with a value of about 420,000 US Dollars. These needs are met through imports from aboard. The raw materials for alginate, namely brown seaweed (Phaeophyceae) are very abundant in Indonesian coastal zones, but its stock level is not yet known. This study aims: to explore the biomass of brown seaweeds along the coastal areas of Bitung-Bentena, North Sulawesi Province by mapping their habitat, distribution and density using the effective and efficient tool of satellite remote sensing; and to compile preliminary results on the quality of alginate extracted from brown seaweeds. Result show that based on the isocluster analysis of Landsat-7 ETM+ and field sampling, we successfully classified 6 different habitats in the reef flats of Bitung-Bentena with map which had accuracy of 73.6%. The total area of brown seaweeds was approximately 127.1ha. Meanwhile, from 53 field transects, there were 6 species of brown seaweed with an average density for all species of 690.4 grams/m2. Thus, the biomass of brown seaweed was 2,133.5 tons wet weight, equal to 29.9 tons of alginate. This study proves that satellite remote sensing is an effective and efficient tool for such kind of works, and must be continued along the entire of Indonesian coastal zones. In this study, the preliminary results on extracting alginate from brown seaweed are also presented.
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