Digital library

  • A Comparative Economic Analysis of Two Seaweed Farming Methods in Tanzania

    The national Seaweed Development Strategic Plan recently adopted by the Tanzanian government calls for expansion of seaweed farming which has proven to be an important income generator for coastal communities and an export earner for the country. The plan calls for the expansion of farming of Kappaphycus alvarezii, locally called cottonii. Although cottonii is the higher priced variety, it is more environmentally sensitive, leading to disease problems and die-offs. The Sustainable Coastal Communities and Ecosystems (SUCCESS) program has piloted a deep-water floating line method of cottonii farming in Mlingotini village of Bagamoyo District to test whether this method can reduce die offs but still be an economically viable option for farmers.

    A comparative economic analysis of two different methods for farming cottonii –– the traditional peg and line off-bottom method and the deep-water floating line method –– is presented in this paper. It compares the productivity and economic returns of the two different methods for farming as well as compares the financial returns of buyer-dependent and independent seaweed farmers. The findings and recommendations are that:

    The floating line method is economically superior to the traditionally used off-bottom method of farming cottonii and therefore should be promoted. There is a significant difference between the productivity of the off-bottom and floating line plots attributable to the floating line method’s advantage of reducing die-offs that occur using the off-bottom method. The floating line method also creates a seed bank that minimizes the amount of time a farmer spends trying to produce seed after a die-off, therefore; combining floating and off-bottom farms is advantageous. The floating line plots also act as fish-aggregating devices and by using dema traps, seaweed farmers can also harvest a substantial amount of fish.

    Independent seaweed farming is economically superior to buyer-dependent farming. However, independent seaweed farming should be promoted with the caveat that independent farmers must raise their own capital to purchase inputs and assume greater risk. Independence is advantageous for both the off-bottom and floating farm method regardless of whether loans are needed or not for initial investments in farming. However, the greater profit potential of independent seaweed farming needs to be weighed against the greater economic risks to farmers that also accompany it.

    It is recommended that independent farmers expand their current production of cottonii and that credit be provided for this purpose. Production can be expanded by expanding existing farms or increasing the number of farms. Household farming strategies will be based on time availability and economic comparability of seaweed versus other livelihood options. Expanded production can be catalyzed if farmers have access to loans for capital investment. However, traditional micro-credit lenders such as FINCA require loan payment schedules that are inconsistent with the production and sales cycle of seaweed farming. Alternative microcredit schemes such as savings and credit cooperatives should be considered that can provide loan repayment schemes more consistent with the production and sales cycle of seaweed farming.

    Resource management, and in particular, marine zoning, must be integrated with seaweed farming. Stakeholder -based marine zoning of seaweed farming areas is needed to reduce spatial use conflicts with other uses such as tourism and fishing. 

    Author(s): Flower E. Msuya , Mwanahija S. Shalli, Karen Sullivan, Brian Crawford, James Tobey, Aviti J. Mmochi

  • A comparative environmental life cycle assessment of hatchery, cultivation, and preservation of the kelp Saccharina latissima

    Seaweed cultivation and processing industries could contribute to sustainable blue growth and the European bioeconomy. This article contributes a case study evaluation of environmental sustainability of preserved brown seaweed Saccharina latissima by means of environmental life cycle assessment of a pilot facility in Sweden. The study accounts for nutrient bioremediation and carbon capture and includes two alternative hatchery processes, a 2-ha longline cultivation, and four alternative preservation methods (hang-drying outdoors, heated air-cabinet drying, ensiling, and freezing). The study found that as a result of carbon capture and nitrogen and phosphorus uptake (bioremediation) by seaweed, more CO2 and PO4 equivalents are (temporarily) absorbed than emitted by the supply chain. The extent of emissions is most affected by preservation methods undertaken. Impact profiles of the supply chain show that the greatest impact shares result from freezing and air-cabinet drying, both the two most energy-intensive processes, followed by the cultivation infrastructure, highlighting strategic optimization opportunities. Hatchery processes, harvesting, and the low-energy ensilage and hang-drying outdoors were found to have relatively small impact shares. These findings presage the environmentally friendliness of seaweed-based products by documenting their potential to mitigate eutrophication and climate change, even when taking a life cycle perspective.

    Author(s): J.-B. E. Thomas, M. Sodre ́ Ribeiro, J. Potting, G. Cervin, G. M. Nylund, J. Olsson, F. Grondahl, E. Albers, I. Undeland, H. Pavia

  • A comparison of protocols for isolating and concentrating protein from the green seaweed Ulva ohnoi

    We compared protocols to isolate and concentrate protein from the green seaweed Ulva ohnoi. We quantified the effect of three factors on protein and essential amino acid yields and concentrations in protein isolates and residuals in a factorial experimental design. The three factors were starting material (as dry and milled or fresh and pulped), aqueous solvent-to-biomass ratio (20:1 or 5:1 v/w) and the incubation time in the aqueous solvent (incubated for 16 h at 30 °C or incubated for <1 min at ambient temperature). The protein isolation protocols increased the concentration of protein, total essential amino acids, methionine and lysine ~3 to 5- fold compared to whole U. ohnoi and were considerably more effective than the different protein concentrating combinations, which only increased protein and amino ac- id concentrations by 30–40 % in the residual biomass. The use of fresh and pulped biomass as the starting material, an incubation time of <1 min at ambient temperature and a low aqueous solution volume resulted in the highest pro- tein isolate yield of 22 % of the protein found in seaweed. This study demonstrated that proteins from U. ohnoi were most effectively isolated by adopting protocols for terres- trial leaves compared to the protocols employed for seed crops as traditionally applied to seaweeds.

    Author(s): Alex R. Angell, Nicholas A. Paul, Rocky de Nys

  • A Preliminary Illustrated Field Guide to The Common Marine Algae of the Cook Islands (Rarotonga and Aitutaki)

    Seaweeds or marine algae comprise a grouping of very diverse photosynthetic organisms whose relatively simple vegetative structure is called “ thallus ”. They have been traditionally set apart from higher plants, whose more complex level of organisation is differentiated as stems, leaves and roots, through which run sap-carrying conductive tissues.

    Algae are autotrophic organisms, which are able to manufacture their own organic molecules from elements containing carbon and nitrogen. Their energy is obtained directly from sunlight, which is trapped by the pigment chlorophyll during the process of photosynthesis. Water and mineral nutrients are directly taken from their environment through their cell surfaces.

    While seaweeds are an essential part of the marine ecosystem, they are mostly overlooked as they are overshadowed by their more conspicuous neighbours such as corals, fishes and molluscs. Nevertheless, they occupy the bottom of the food chain and are direct food for a large number of marine organisms, and also for humans in many parts of the world. A host of useful products are also extracted from marine algae, with applications ranging from cosmetics to medicine and the food industry.

    Disruptions in seaweed growth patterns caused by unnatural sources such as pollution and deliberate introduction can have quite harmful consequences on the marine ecosystem. For instance, in the Mediterranean sea, the tropical green alga Caulerpa taxifolia has in recent years become a pest, as it clogs waterways and displaces other marine organisms after having escaped from an aquarium in Monaco. In the Cook Islands, fluctuations in the numbers of the patito or sea hare (Stylocheilus longicauda) has been linked to the disappearance and reappearance of the blue-green alga Lyngbya majuscula, on which it primarily feeds. These fluctuations have been also linked to blooms in the green alga Boodlea kaeneana, which could be caused by an increase in organic nitrates flushed into the lagoon (for instance from piggeries) or an increase in global seawater temperatures caused by climatic factors such as the greenhouse effect and El Niño.

    It is hence important to recognise seaweeds in their natural environment, and realise their major role in the balance and well-being of the coral reef community, on whose biodiversity and health the livelihood of many island communities such as the Cook Islands closely depends

    Author(s): Antoine D. R. N’Yeurt

  • Advances in Extraction Methods to Recover Added-Value Compounds from Seaweeds: Sustainability and Functionality

    Seaweeds are a renewable natural source of valuable macro and micronutrients that have attracted the attention of the scientists in the last years. Their medicinal properties were already recognized in the ancient traditional Chinese medicine, but only recently there has been a considerable increase in the study of these organisms in attempts to demonstrate their health benefits. The extraction process and conditions to be used for the obtention of value-added compounds from seaweeds depends mainly on the desired final product. Thermochemical conversion of seaweeds, using high temperatures and solvents (including water), to obtain high-value products with more potential applications continues to be an industrial practice, frequently with adverse impact on the environment and products’ functionality. However more recently, alternative methods and approaches have been suggested, searching not only to improve the process performance, but also to be less harmful for the environment. A biorefinery approach display a valuable idea of solving economic and environmental drawbacks, enabling less residues production close to the much recommended zero waste system. The aim of this work is to report about the new developed methods of seaweeds extractions and the potential application of the components extracted.

    Author(s): Gabriela S. Matos, Sara G. Pereira, Zlatina A. Genisheva, Ana Maria Gomes, José A. Teixeira, Cristina M. R. Rocha

  • An appraisal on commercial farming of Kappaphycus alvarezii in India: success in diversification of livelihood and prospects

    There is an urgent need for diversifying livelihoodof low-income artisanal fishermen due to rapidly dwindlingfishery resources. CSIR-Central Salt and Marine ChemicalsResearch Institute takes pride in being first for pioneeringKappaphycus alvareziicultivation, heralding an era of com-mercial seaweed farming in India. The invention of liquefyingfresh seaweed biomass to obtain two products in an integratedmanner, one being a granular residue rich inκ-carrageenanand the other being sap rich in potash and micronutrients(ca. 2 %w/v), with proven efficacy has provided a boost tocommercial farming. The production has been substantiallyincreased from 21 dry tonnes in 2001 to 1490 dry tonnes in2013 with concomitant purchase value of <4.5 to 35 Rs kg−1(dry). India is fast emerging as important production center inSoutheast Asia forK. alvareziiproduction with estimated765,000 man-days of employment, having annual turnoverof around Rs 2 billion. At present, commercial farming iscarried out following three techniques, namely floatingbamboo raft, tube net, and longline method of which formertwo are widely practiced. Thecultivation activity is wellestablished in southern state of Tamil Nadu and progressingrapidly to other areas namely Gujarat, Andhra Pradesh, andMaharashtra. The socioeconomic benefits accrued in this pro-ject are overwhelmingly positive, but evidence-based policiesare required for addressing prevailing environmental issues.The steps toward developing value-added products with nicheapplications coupled with biotechnological interventionsaimed at seed production through tissue culture for developingelite germplasm, etc. could further improve the prospects oftaking this project to pan India level. The present review pro-vides a detailed account of developments of commercial farm-ing that has witnessed successful diversification of livelihoodconsistently for the last 10 years.

    Author(s): Vaibhav A. Mantri , K. Eswaran, M. Shanmugam, M. Ganesan, V. Veeragurunathan, S. Thiruppathi, Abhiram Seth

  • AQUACULTURE COLLABORATIVE RESEARCH SUPPORT PROGRAM

    Best management practices (BMPs) were developed for management of bottom soil in freshwater aquaculture ponds in Thai- land. These practices were based on a survey of production practices in tilapia, catfish, carp, and freshwater prawn culture and upon findings of studies of physical and chemical characteristics of bottom soil from ponds of different ages. Fifteen BMPs were designed to encourage the following: pond dry-out between crops; aeration of bottoms by tillage; liming of acidic bottoms; use of sedimentation basins; responsible disposal of sediment; erosion control; application of proper construction techniques; reduction in suspended solids in effluents. The BMPs have been translated into Thai for distribution to farmers, and several of the BMPs have a high rate of adoption by Thai farmers.

    Author(s): Hillary Egna, Karl Kosciuch

  • Cadmium and copper toxicity in three marine macroalgae: evaluation of the biochemical responses and DNA damage

    Marine macroalgae have evolved a different mechanism to maintain physiological concentrations of essential metal ions and non-essential metals. The objective of the present work was to evaluate the antioxidant response and DNA damage of copper and cadmium ions in three halophytes, namely, Acanthophora spicifera, Chaetomorpha antennina, and Ulva reticulata. Accumulation of copper was significantly higher (P < 0.05) than that of cadmium. Biochemical responses showed that copper was considerably more toxic than cadmium (P < 0.05). Decreases in glutathione content and fluctuations of super oxide dismutase, catalase, and glutathione peroxidase activities were observed corresponding to time and concentration of exposure. Interestingly, it was also observed that antioxidant levels decreased as a result of metal accumulation, which may be due to free radicals generated by copper and cadmium in seaweeds. The present study also showed that copper and cadmium increased oxidative stress and induced antioxidant defense systems against reactive oxygen species. The order of toxicity for metals in the studied seaweeds was U. reticulata > A. spicifera > C. antennina. DNA damage index analysis supported that copper was significantly (P < 0.05) more toxic than cadmium. Bioaccumulation, biochemical responses, and DNA damage observed in the here analyzed marine macroalgae after exposure to selected metals indicate that these marine organisms represent useful bioindicators of marine pollution.

    Author(s): M. Yokesh Babu , L. Palanikumar, N. Nagarani, V. Janaki Devi, S. Ramesh Kumar, C. M. Ramakritinan, A. K. Kumaraguru

  • Can we not mitigate climate change using seaweed based biostimulant: A case study with sugarcane cultivation in India

    Strategies for sustainably increasing sugarcane productivity without any negative implications to the environment are challenging. In the present investigation, field trials were conducted to demonstrate the potential of an agro-technique involving foliar applications of Kappaphycus alvarezii seaweed based biostimulant in combination with recommended rate of synthetic fertilizers (RRF) for sustainably enhancing sugarcane production and mitigating environmental impacts. Kappaphycus seaweed extract (KSWE) applied at 5% concentration enhanced cane productivity by 12.5 and 8%, respectively, in plant and ratoon crops. Interestingly, the treatment involving 6.25% KSWE +50% RRF showed yield parity (p < 0.05) with control (water+100% RRF) in ratoon while there was 7.9% reduction over control in plant crop with a concomitant savings of 50% RRF. These results revealed that KSWE application in addition to recommended rate of fertilizer application, can reduce gap between potential and real yield which otherwise requires application of incremental inputs in the form of synthetic fertilizers to obtain similar yields. The findings confirmed our hypothesis that the use of KSWE not only results in hypothetical savings in the incremental application of synthetic fertilizers but also can be used for achieving target yields sustainably. The sugar yield too was enhanced thus increasing the returns on investment. The technique is practically feasibility and scalability. The potential of the KSWE in lowering GHGs is manifested by the way of saving at least 260 kg CO2 equivalents (Mg cane production)−1 ha−1 when applied at 5% concentration. This would translate in to savings of ca. 9.3 million Mg of CO2 equivalents if one assumes employing KSWE for at least 10% of the total cane production in India for the year 2015–16. Therefore, the present study advocates a paradigm shift in policy to encourage use of biostimulants in the context of mitigating adverse effects of global climate change and expecting better returns from sugarcane cultivation.

    Author(s): Arup Ghosh, Sudhakar T. Zodape, Ramakant Rai, Sudhir Kumar Shukla, Sushil Solomon, K.G. Vijay Anand, Ishwar Singh

  • Case studies of seven commercial seaweed resources

    Seven case studies are presented on commercial seaweed resources; five on wild crops, respectivelyAscophyllum nodosum, Chondrus crispus, Gelidium, Laminaria longicrurisandMacrocystis,are provided along with case studies of the farmed crops ofEucheumaandLaminaria japonica.Individually the cases range from descriptions of the wild crops and their management to themanaged production of farmed crops including, in several examples, some information on economics and/or processing. These initial seven cases range from those emphaizing but one speciesfrom but one part of one country, to studies of a genus as it occurs commercially throughout the world.

    Author(s): M. S. Doty, J.F. Caddy, B. Santelice

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