The aim of the presented investigation was to test the sensibility of macroalgal aquaculture in offshore wind farms in the North Sea and to find arguments for the choice of appropriate sites among the planned wind farms. Based on experience with an offshore aquaculture farm of Laminaria saccharina conducted in 2002, we assessed the maximum hydrodynamic forces affecting farmed algae by applying the model software bWaveLoadQ. Drag measured in a towing tank was considerably higher on algae with a more ruffled margin and wider blade collected from sheltered environments than on flat and narrow farmed Laminaria despite comparable blade areas. Drag varied according to frond size, current velocity and acceleration reaction. Dislodgement of laminarian holdfasts and the forces necessary to break the stipe depended on blade length and surface area. Neither did our measured nor our calculated values of drag exceed those forces, provided the algae had been grown in a current N1ms1 . Even in storm conditions with maximum current velocities of 1.52 m s1 and wave heights of up to 6.4 m can cultivated L. saccharina withstand the high energy environment.
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There is a growing concern about the ability to produce enough nutritious food to feed the global human population in this century. Environmental conflicts and a limited freshwater supply constrain further developments in agriculture; global fisheries have levelled off, and aquaculture may have to play a more prominent role in supplying human food. Freshwater is important, but it is also a major challenge to cultivate the oceans in an environmentally, economically and energy- friendly way. To support this, a long-term vision must be to derive new sources of feed, primarily taken from outside the human food chain, and to move carnivore production to a lower trophic level.
The main aim of this paper is to speculate on how feed supplies can be produced for an expanding aquaculture industry by and beyond 2050 and to establish a roadmap of the actions needed to achieve this. Resources from agriculture, fish meal and fish oil are the major components of pellet fish feeds. All cultured animals take advantage of a certain fraction of fish meal in the feed, and marine carnivores depend on a supply of marine lipids containing highly unsaturated fatty acids (HUFA, with ≥3 double bonds and ≥20 carbon chain length) in the feed.
The availability of HUFA is likely the main constraint for developing carnivore aquaculture in the next decades. The availability of fish meal and oil will decrease, and the competition for plant products will increase. New harvested resources are herbivore zooplankton, such as Antarctic krill and red feed, and new produced resources are macro- algae, transgenic higher HUFA-producing plants and bacterial biomass.
These products are to a lim- ited extent components of the human food chain, and all these resources will help to move cultured carnivores to lower trophic levels and can thereby increase the production capacity and the sustain- ability of the production. Mariculture can only become as successful as agriculture in the coming cen- tury if carnivores can be produced at around Trophic Level 2, based mainly on plant resources. There is little potential for increasing the traditional fish meal food chain in aquaculture.
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Industrial effluents such as pharmaceutical residues, pesticides, dyes, and metal processes holds abundant valueadded products (VAPs), where its recovery has become essential. The purpose of such recovery is for sustainable treatment, which is an approach that considers the economic, social, and environmental aspects. Microalgae with its potential in the recovery process from effluents, can reduce energy usage of waste management strategies and regenerate nutrients such as carbon, phosphorus, and nitrogen. Microalgae cultures offer the use of inorganic materials by microalgae for their growth and the help of bacteria to produce biomass, thus, resulting in the absence of secondary emissions due to its ability to eliminate volatile organic compounds. Moreover, recovered bioactive compounds are transformed into bioethanol, bio-fertilizers, biopolymer, health supplements and animal feed. Therefore, it is significant to focus on an economical and efficient utilization of microalgae in recovering nutrients that can be further used in various commercial applications.
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Seaweed aquaculture is a rapidly growing component of marine food production, but the capacity to control seaweed growth lacks behind that of land agriculture. Seaweed growth requires nutrients, acquired from dissolved pools through their fronds, and light, and, as such may also be density-dependent, but general relationships between seaweed growth, nutrient concentration and incident irradiance are not yet available. We used a dataset of 1729 experimental assessments of seaweed specific growth rates and density under various nutrient and irradiance levels retrieved from the published literature to examine the relationship between seaweed growth, density, irradiance, and nutrient concentration. This analysis confirmed strong density-dependence of seaweed specific growth rates, and further confirmed that nutrient and irradiance limitation strongly impose density-dependent seaweed growth. These findings demonstrate that nutrient and irradiance limitation modulate density-dependent seaweed growth, and can help maximize growth rates in seaweed aquaculture, a rapidly growing component of global aquaculture production, by manipulating stocking density where nutrients are scarce and/or underwater light penetration poor.
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Norwegian research scientists from the SINTEF are convinced that kelp may share many of the applications of soy and oil in the fish farming industry. “We can break seaweed down into their basic constituents and recombine them to make useful products,” said researcher Silje Forbord at SINTEF. “We can use seaweed to make clothes, furniture materials, food packaging, drinking straws and biodegradable bottles,” Forbord said.
The team has been active in the forefront of a research project called MACROSEA, which is providing new insights into the potential of seaweed farming in Norway. The project has also succeeded in developing innovative solutions that will assist in industrializing the Norwegian seaweed sector.
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Cultivation of seaweed in the US faces big barriers: the lack of commercial-scale processing, competition with lower-cost Asian imports, inconsistent oversight, and increasing food safety concerns, say farmers and researchers.
These problems are preventing farmers from harnessing seaweed’s full potential.
“Seaweed globally is upwards of a $12-billion industry, just growing and wild harvesting it, whether for cosmetics, filler for food or for human consumption. We are really in a good situation here in North America to provide the best seaweed in terms of nutrient and health value to the rest of the world due to our water-quality regulations. But we are so far behind in terms of growing in the oceans and aquaculture,” says Greg Martino, co-owner of Cottage City Oysters on Martha’s Vineyard.
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Algae isn't typically associated with cattle feed, but a Texas AgriLife Research scientist and graduate student have found some interesting results that may change this during their three-phased study.
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Algae remain an attractive target for bioenergy applications over the longer term because of their high photosynthetic efficiency. However, near-term prospects for primary algae-based energy/fuels production remain poor due to the cost of cultivating and harvesting algae. While there has been substantial technical progress on algae-based bioenergy production in recent years, persisting low fossil fuel prices are causing the algae-based industry to shift its focus from biofuels/bioenergy products to higher value (non-fuel/energy) products that can be profitable today. Ultimately, the vision is that algal biomass-based co-products will provide the additional revenue needed to reduce the net cost of producing algal-based biofuels. As such, a biorefinery approach that enables multiple high-value products to be produced will be essential to fully valorize algal biomass and enable bioenergy coproduction. To accelerate implementation of algae-based production, progress in minimizing the energy, water, nutrients and land use footprints of integrated algal-based operations needs to be a primary objective of future larger scale demonstrations. This presentation will summarize findings of a recently completed IEA Bioenergy report on the status and prospects for using microalgae and macroalgae as feedstocks for biofuels and bioenergy production; the report is available at www.ieabioenergy.com. The scope of the areas covered includes international activities advancing bioenergy and non-energy bio-products from algae, bioenergy from macroalgae (both cast and cultivated seaweeds), distinct biochemical and thermochemical conversion pathways, biorefining opportunities, as well as process economics and sustainability issues.
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The importance of seaweeds as a marine resource has recently been emphasized due to the increasing demand for them as food and raw materials in the manufacture of industrial colloids, e.g. agars, carrageenan, and alginates which find varied uses in industries. In addition, the production of seaweeds through culture is now recognized as a very productive alternative source of livelihood and employment especially in developing countries in tropical Asia where a large portion of the shallow coastal fishery resources have been or are being depleted. With some exception, the present seaweed production in the tropics comes from the harvesting of wild stocks which if not regulated can result to the depletion of these stocks. Thus, it is necessary that culture and management of local stocks should be developed for the economic species to enhance and maintain their productivity.
The farming and gathering of economic species of seaweeds are labour-intensive form of activities which can help increase employment opportunities among the coastal communities and thus play an important role in enhancing their socio-economic conditions. The general ecology and productivity of shallow subtidal areas have been shown to greatly improve upon the introduction of seaweed farming. Additionally, the introduction of a management scheme for the gathering of local stocks shall also help conserve them.
The training of fishery extension workers, farm managers, and future seaweed farmers in the practical methods of culturing economic speices on Eucheuma, Gracilaria and Caulerpa, will promote further expansion of seaweed farming; on the inventory and assessment of local stocks of useful seaweeds shall promote and enhance the productivity and conservation of these species. It is for these reasons that this regional training was organized and implemented.
This training course was designed to develop and promote qualified expertise in seaweed farming to help in food production, provide cash crops and open new alternative employment to enhance the socio-economic welfare of coastal communities as well as offer practical training on seaweed farming and management of natural stocks of economically important seaweed species; improve technical knowledge about seaweeds and acquire practical skills in seaweed farming techniques, processing and marketing.
The course consisted of lectures and field training on the culture of Eucheuma, Caulerpa and Gracilaria, assessment and rational utilization of natural stocks of ecomomic species such as Sargassum, post-harvest and quality control of the produce and field study visits to existing farms. Basic lectures on the biology and ecology of seaweeds as well as methods on the identification and preparation of seaweed materials for research were also included as background information.
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This report brings out the marine algal resources of the Tamil Nadu coast as the outcome of the Marine Algal Survey undertaken during 1971-76 as a co-ordinated project by the three organisations a Department of Fisheries, Government of Tamil Nadu, The Central Marine Fisheries Research Institute and the Central Salt & Marine Chemicals Research Institute. The survey was conducted both intensie ely covering all the marine algal species and extensively covering a wide coastine in the intertidal and sub - tidal beds. Though found in moderate quantities in comparison with the rich seaweed in the world,the marine algal resources estimated now are found to be quite considerable.
In spite of the fact that some of the economic seaweeds have been commercially exploited from this region,there is still a possibility for greater harvesting and utilization of the brown algae particularly the species of Sargassusm and Turbinaria for alginate industry and the species of Gracilaria for agar industry in our country, However,resources of Gelidiella aceros need to be conserved. The scope for harnessing other available marine algal resources and their proper utilization, say for extractives, fertilizer, etc. are indicated .
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Marine Agronomy Group, CAFNRM, UH-Hilo
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