Gracilaria verrucosa was successfully cultivated in a pond based aquaculture system at Narakkal. Kerala. India. Daily growth rate of seaweed was found to be maximum (19.22%) during 60 days of introduction. The growth. pigment constituents and the yield of agar were influenced by the environmental parameters. Agar yield and photosynthetic pigments declined in the initial period up to 50 days due to acclimatization of the plants lo new environment which was collected from Chennai, India and introduced in the pond at 'Narakkal. After 60 days, the algae started establishing in the bottom of the pond and an initial harvest of 230.25 kg was harvested after 90 days of culture period. Further regular harvest was made at every 10 days interval yielding 1015 kg of Gverrucosa during the culture period. The agar content ranged between 7-14.8% and bottom sample exhibited better yield of. agar than the plants cultured in the floating raft.
Digital library
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The physical aspects of ocean kelp farming were studied in the context of farms sited in nearshore coastal waters. Analyses and models were employed to investigate the physical oceanographic and ocean engineering problems underlying conceptual designs of nearshore kelp farms. The areas addressed include interactions between ocean coastal currents and kelp farms, distribution and transport of fertilizer in and around the farm, interactions between surface water waves and kelp farms, effects on adjacent shorelines of wave field modifications due to the farm, and wave forces on kelp plants.
For the range of coastal conditions and farm configurations examined, it was found that the flow of ocean currents is significantly retarded within the farm and flows are deflected in a narrow band around the farm; substantial losses from the farm of applied fertilizer result from advection within the farm; water wave heights can be significantly reduced within the farm due to the kelp, and a shadow zone of reduced waves may extend significantly shoreward of the farm; the shadow zone may, under certain conditions, result in shoreline modification; and wave forces on the kelp have inertial components of the same order of magnitude as buoyancy forces.
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Macroalgae, or seaweeds, are multicellular – usually macroscopic – plant-like organisms that generally live attached to rock or other hard substrata in coastal areas. There are about 10,000 species of algae, of which 6,500 are red algae (also named Rhodophyta), 2,000 are brown algae (Phaeophyceae), and 1500 are green algae (Chlorophyta and Charophytes). These three groups have very distinct evolutionary histories and display specific ultrastructural and biochemical features (e.g. pigments).
Seaweeds are increasingly employed as feedstock around the world, with an annual production of 30Mt for a ~ €8B value. Seaweeds are thus a promising bioresource for the future and demands for high-value seaweed-derived compounds (cosmetics, food) are on the rise in Europe. However, the production of Europe lags behind that of Asian countries despite its large exclusive economic zone, its high seaweed biodiversity and its international leadership in fundamental research on macroalgae.
Drawing on our long-term experience in plant production and domestication in general, as well as on current knowledge of European and worldwide marine ecology, climate and trade, we explore the reasons for this lag, and offer recommendations for improving seaweed cultivation and harvest.
Based on a detailed analysis of current seaweed aquaculture practices, regulations, health benefits and consumer demands, these guidelines aim to foster sustainability and protection of the marine environment. These guidelines also include expert opinions and assessments from the academic, private and associative sectors, based mainly in Europe, but also on other continents. With this wide scope and using a field-based and scientific approach, we have aimed to produce a robust prospective reference document to support policy-makers and the elaboration of future European regulations.
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Biofuels Co-products Workshop Hosted by the Aquatic Feeds & Nutrition Dept. Oceanic Institute.
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We investigated the patterns and controls of dissolved organic carbon (DOC) production by the giant kelp (Macrocystis pyrifera) using data from short-term in situ incubations of entire blades and portions of stipes. These data were incorporated into an empirical model of reef-scale net primary production (NPP) at Mohawk Reef in southern California, U.S.A. for an 8-yr period. Rates of DOC release of incubated blades varied unpredictably with time of year, but were significantly related to the irradiance at the sea surface during the incubations. The growth stage, C/N ratio, and epiphyte load of the blades and the temperature of the ocean during the incubations had no discernable effect on rates of DOC release. Blades produced on average 2–3 times more DOC than stipes, and stipes and blades produced on average 30% and 80% more DOC respectively during the day compared to the night. Modeled DOC NPP at the reef scale was on average highest in summer and spring (0.5 g C m22d21) and lowest in winter and autumn (0.31 g C m22d21), but it varied greatly among years for any given season as large oscillations in standing biomass led to corresponding fluctuations in reef-scale DOC NPP. The fraction of NPP released as DOC was highly variable when examined at the monthly time scale, but became much more stable at seasonal and annual time scales averaging 14% of total NPP
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The Philippines has abundant aquatic resources. Seaweeds are one of these aquatic products which are found in lagoons and reed areas all over the country. The country is one of the few around the world which pioneered in the farming of these plants in substantial quantities. The Philippines is noted for the culture of seaweeds along with Japan, China, Korea, and Taiwan.
Seaweeds are a good source of colloidal materials which are used as gelling agents, emulsifiers, stabilizers, in pharmaceutical, cosmetic, and food products. They also contribute to important food items, fertilizers, and animal feeds. According to the Food and Agriculture Organization (FAO), commercial production of seaweeds through farming is at present limited to a few countries in East Asia making these a high value crop with a high demand in the world market.
Sargassum is a genus of brown algae (class Phaecophyceae) macroalga (seaweed) under the order Fucales. Numerous species are distributed throughout the temperate and tropical oceans of the world, where they generally inhabit shallow water and coral reefs. However, the genus may be best known for its planktonic (free- floating).
Sargassum as algae has developed multicellular structure. Sargassum is characterized by long, highly branchy fronds which gives its leafy appearance. Many have bladders filled with air which help these float. In the open water, these bladders keep the Sargassum free-floating near the surface of the water so that it can photosynthesize energy. In area where Sargassum is anchored to the bottom, these bladders help the seaweed stretch towards the light, creating the forests of seaweed effect which gently undulate with the water waves.
There are a number of uses for Sargassum. In some regions, for example, it is collected as fertilizer. It is also a food source, especially in Japan, where it may be added to soups and fermented with other ingredients in soy sauce to create a specific flavor. Many animals use Sargassum as home, as the seaweed provides shelter due to their abundant fronds, along with a hiding place from predators and a source of food.
Seaweeds have been harvested because of their significant contributions in many ways. The most obvious use of these multicellular is a food source. People from different cultures have discovered that many seaweeds are eligible, especially some of the red and brown algae. They are consumed in a variety of ways. They may be raw, cooked or dried. In addition, seaweeds can also add variety and taste to bland foods. The reason why the farming or mariculture of seaweeds is a growing business is because they are good source of some vitamins, minerals, and some are said to contain substantial amounts of proteins.
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Alaria esculenta is a brown seaweed with a great potential for biomass production due to its high productivity and high content of carbohydrates, proteins, vitamins, minerals and bioactive compounds like phlorotannins and pigments. Alaria cultivation is performed either by collection and settlement of zoospores on ropes to develop seedlings, or by production of the seedlings from vegetative gametophyte cultures. Contrary to the zoospore technique, the use of gametophyte cultures has the potential to provide a constant, year-round supply of seedlings. There is a need for optimizing the production methods such as the maintenance of the gametophyte cultures, gametogenesis, seeding process and deployment time. The purpose of this dissertation is to optimize several parameters involved in Alaria cultivation using vegetative gametophytes and provide qualitative and quantitative information related to kelp phlorotannins. Optical density and in vivo fluorescence were evaluated as an alternative method to estimate gametophyte biomass. Both methods showed linearity with the dry weight. The cultures were also supplemented with a possible growth enhancer and the effect evaluated on the cultures, however no growth improvements were noticed on these cultures. When the seedlings production is initiated, the fertility of vegetative gametophytes needs to be switched on. The fertility induction was evaluated with three different photoperiod regimes under white light, where the best performance was accomplished by 23 hours light over 8 days. The seeding density is the next step to optimize seaweed industry. Higher and lower densities bring several disadvantages to the development of the sporophytes. Thus, four densities of fertile gametophyte cultures were tested, where a density per dry weight of 0.8 mg/mL produced the most acceptable number of sporophytes on the twines. For the estimation of sporophyte growth, manual measurements, such as sporophytes counting and length measurement, are extremely time-consuming methods. An alternative method based on image analysis was tested to estimate the percentage of growth of the seedlings and compared with the manual method. The image analysis method was shown to have a good relationship with the sporophyte measurements, bringing a faster and easier way to estimate the seedlings growth. A. esculenta and S. latissima could represent a viable source of phlorotannins (PHL) due to the fast and efficient grow of these species. The juvenile stages of these species had an average of 4.11 and 3.08 mg PHL/g algae, respectively. It was also observed that the phlorotannin content in the Alaria gametophytes increased during fertilization. Two forms of phloroglucinol were documented in both species but due to the lack of studies related with the phlorotannin characterization of these species no more compounds were identified.
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This overview report addresses opportunities for the development of the Pacific Islands’ mariculture sector in general terms. More specific analysis of opportunity in particular
countries is presented in the five accompanying country reports (Cook Islands, Fiji, Papua New Guinea, Republic of the Marshall Islands and Solomon Islands).
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Seaweed aquaculture is a relatively young industry in the United States compared to Asian countries. Early attempts at seaweed aquaculture in California, Washington State, New York and the Gulf of Maine in the 1980s and 1990s did not result in commercial production but provided important lessons. Since 2010, commercial cultivation of kelp (Saccharina latissima, Laminaria digitata, and Alaria esculenta) and other seaweeds (Palmaria palmata and Porphyra umbilicalis) began in the Gulf of Maine and Long Island Sound. Seaweed aquaculture is now a fast-growing maritime industry, especially in New England. If seaweed aquaculture is to maintain its momentum, it is important to (1) emphasise the environmental benefits; (2) domesticate a variety of local species; and (3) diversify seaweed products for food, animal feed, phycocolloids, cosmeceuticals, nutraceuticals, and ultimately biofuels if it becomes economically viable due to the cost of production. The exclusive economic zone (EEZ) of the United States offers opportunities for expansion of seaweed aquaculture in an area greater than the entire land mass of the United States and with limited user conflicts. This study reviews the past and current status of seaweed aquaculture in the United States and discusses potential opportunities and challenges of open-water seaweed aquaculture.
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Experiments were conducted with the receptacles of reproductive plants of Sargmsum wight;; (Greville) 1. Agardh and Tllrbinaria conoides (1. Agardh) KuelZing to study the effect of different environmental factor.; on the oospore output. The ability to liberate spores and the quantity of spores shed in these two brown algae varied under the environmental factors tested. In general, submerged condition of plants, long day condition at low illuminance, seawater of 30 to 40%. salinity and 25 to 35'C temperature were found to be suitable for maximum shedding of oosporcs in these two algin yield ing plants.
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Marine Agronomy Group, CAFNRM, UH-Hilo
200 W. Kawili st., HI 96720, USA
Contact: Marine.Agronomy.Group@gmail.com
Funding for this web portal is provided by the World Wildlife Fund and the University of Hawaii-Hilo.