The world-wide increasing demand for seaweeds and seaweed products as items of food and raw material for the manufacture of industrial products as agar, carraheenan, and alginate has been the main factor which has encouraged the development of production technologies of economic species of seaweeds. This paper is a brief review of the current production technologies for four tropical seaweed genera, namely. Eucheuma, Kappaphycus, Gracilaria and Caulerpa. The related production problems and needs are also described.
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This work shows the technical and economical aspects of seaweed farming for the production of phycocolloids or marine gums. Two different cultivation systems were used in four different sites inhabited by Wayúu fisherman communities in the townships of Cabo de La Vela and Carrizal, Guajira Peninsula, Colombia. The productivity and the growth rate of three commercial important macroalgae species, as well as the production costs, investment and returns of 0,5 ha marine farms, taking into consideration the design and construction of cultivation units made with cheap and available materials. The implementation of these farming systems could lead for the technological transfer of the locals. The income obtained through seaweed farming could benefit a large part of the coastal community as an additional and complementary cash crop to their traditional activities, including artisan fishing and goat rising, where the majority thrives in conditions of extreme poverty with the highest unmet basic needs index of the country.
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An international group of taxonomists representing the United States, Japan, China, Thailand, Chile, and Vietnam describe the results of a 1999 workshop on the taxonomy of the groups Sargassum, Gelidiales, Gracilariales, Kappaphycus/Eucheuma, and Halymenia. This book, the eighth in a series, contains a special section on the marine algae of Vietnam. The California Sea Grant College Program, in cooperation with the University of Hawaii Sea Grant College Program, sponsored the workshop. It was organized and hosted by the Oceanographic Institute in Nha Trang, Vietnam. The rationale behind the first workshop in 1984 was that progress in seaweed aquaculture and marine natural products chemistry would require a better understanding of commercially interesting species. In these times of accelerated loss of habitat and biodiversity, the series of workshops have had the added benefit of providing lasting records of many species, including drawings and photos. They have also provided a forum at which algal specialists could work together on common regional and international problems.
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The original rationale behind this series of workshops was that progress in seaweed aquaculture and marine natural products chemistry would require that we better understand the taxonomy of commercially interesting species. Though this remains our primary goal, we have also come to appreciate that one of the most serious consequences of habitat destruction around the globe is loss of species diversity, including that of marine algae. Biodiversity has been defined as the collection of species (or distinct genetic entities), communities, and ecosystems occurring a geographically defined region. But describing changes in diversity over time, whether resulting from human activities or natural processes, require historical information based on rigorous species identification.
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The series of workshops of which this one was part rests on the conviction that progress in seaweed aquaculture and marine natural products chemistry will advance appreciably once the taxonomy of commercially interesting species is better understood.
California Sea Grant funded the first of these biennial workshops more than a decade ago - in 1984, at the University of Guam. From the first, Dr. Abbott served as organizer and motivator. Her vision was to bring together leading systematists from around the Pacific Rim to direct their knowledge and insight to the enormous ignorance that prevails about warm-water Pacific algae. She recognized that many of these eminent specialists were not being succeeded by younger generations and thus represented an irreplaceable resource. Further, she believed that the enthusiasm and dedication of workshop participants would overcome any difficulties presented by language and cultural differences.
The progress made at these workshops has been considerable, and we at California Sea Grant, and our colleagues in the other Pacific Sea Grant Colleges, are pleased to have been able to play some small part in making them possible.
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In this section, the new Philippine species of Sargassum, described in English in the previous volume (and illustrated) are validated with Latin diagnoses. These 12 new species are added to the 50 or so "known" species in the large Philippine archipelago.
Two contributions in this volume address those species with furcately branching leaves, or compressed primary branches. The first, by Ajisaka, Noro, Trono, Chiang, and Yoshida, treats the characteristics of the species statistically, thus continuing some of the earlier perspective. The second paper, by Noro, Ajisaka, and Yoshida, places five species in the synonymy of other species, all common or widespread taxa. This indicates that by whatever means, a gradual understanding of the limits of the common Sargassum species is being reached. Inasmuch as some of these species are "old" (e.g., species of C. Agardh, who was among the first to distinguish species within this group), perhaps examination of "younger" species will show that the younger species had been named one or more times previously.
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The growing world population demands an increase in sustainable resources for biorefining. The opening of new farm grounds and the cultivation of extractive species, such as marine seaweeds, increases worldwide, aiming to provide renewable biomass for food and non-food applications. The potential for European large-scale open ocean farming of the commercial green seaweed crop Ulva is not yet fully realized. Here we conducted manipulative cultivation experiments in order to investigate the effects of hatchery temperature (10 and 15 °C), nutrient addition (PES and 3xPES) and swarmer density (500 and 10,000 swarmers ml−1) on the biomass yield and biochemical composition (fatty acid, protein, carbohydrate, pigment and phenolic content) of off-shore cultivated Ulva fenestrata in a Swedish seafarm. High seedling densities were optimal for the growth of this northern hemisphere crop strain and significantly increased the mean biomass yield by ~84% compared to low seedling densities. Variations of nutrients or changes in temperature levels during the hatchery phase were not necessary to increase the subsequent growth in an open-water seafarm, however effects of the factors on the thallus habitus (thallus length/width) were observed. We found no significant effect of the environmental factors applied in the hatchery on the total fatty acid or crude protein content in the off-shore cultivated Ulva. However, low seedling density and low temperature increased the total carbohydrate content and furthermore, high temperature in combination with high nutrient levels decreased the pigment content (chlorophyll a, b, carotenoids). Low temperature in combination with high nutrient levels increased the phenolic content. Our study confirms the successful and sustainable potential for large-scale off-shore cultivation of the Scandinavian crop U. fenestrata. We conclude that high seedling density in the hatchery is most important for increasing the total biomass yield of sea-farmed U. fenestrata, and that changing temperature or addition of nutrients overall does not have a large effect on the biochemical composition. To summarize, our study contributes novel insights into the large-scale off-shore cultivation potential of northern hemisphere U. fenestrata and underpins suitable pre-treatments during the hatchery phase of seedlings to facilitate a successful and cost-efficient large-scale rope cultivation.
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This report is based on discussions held at a two day workshop held in January 2012, co-organised by the Food Climate Research Network and the Oxford Martin Programme on the Future of Food. The workshop was facilitated by Kath Dalmeny of Sustain and funded by the Foresight Programme and the Oxford Martin Programme on the Future of Food.
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Experiments were conducted with sporelings as well as older plants to determine the factors limiting growth on the reef. Plants were placed out at six locations on the reef and biomass production was compared to water quality factors (water motion, temperature, salinity, turbidity, nitrate, ammonia, phosphorous and silicon levels) at each site. The experiment was repeated three times, in spring, summer, and winter. The results showed that ammonia levels in the range of two to ten micromoles controlled the growth of Gracilaria on this reef (r2 = 0.83); no other water quality factors were significantly correlated with growth. Elevated ammonia levels at specific sites were associated with land-based activities that enriched the reef levels of ammonia. These land use practices including cattle pasturage and shrimp farming.
A sustainable production system was developed in which Gracilaria was harvested from the reef or from shrimp effluent ditches, then transferred to cages for additional growout. Plants removed from effluent ditches were found to be highly enriched in nitrogen content, so when transferred to cages they were able to utilize this nitrogen for growth. After three to four weeks in cages, the plants doubled or tripled in weight and were much cleaner than when taken from the reef or ditches. This material was cleaned and sold in Honolulu.
Funding to build a cleaning machine was removed from the budget by USDA. Rather than fabricate a machine, we conducted time-and-motion studies on the hand-cleaning process and identified procedures that could be streamlined to increase the efficiency of post-harvest handling tasks.
Numerous workshops and public demonstrations were held throughout the project, and participation in ogo growing increased to over 30 families as a result. Ke Kua’aina Hanauna Hou and the University of Arizona are producing a revised Limu Growers Manual, which will be self-published by Ke Kua’aina and distributed to participants in the limu project on Molokai. The manual contains: introduction; life cycle diagrams; ogo cultivation procedures; explanation of the ‘Ohana Growers Network and Limu Buyback Program; and a section on marketing fresh and value-added ogo products.
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"The changes taking place [on planet Earth] are, in fact, changes in the human-nature relationship. They are recent, they are profound, and many are accelerating. They are cascading through the Earth’s environment in ways that are difficult to understand and often impossible to predict. Surprises abound."
There are many definitions of "sustainability" as the concept applies to aquaculture. The most popular definition of sustainable development is to "meet present needs without compromising the ability of future generations to meet their needs" adopted at a United Nations conference in 1987. Most definitions of sustainability are synonymous with "environmental sustainability" of air, water, and land systems. Sustainability is however a concept broader than examining the sitespecific environmental impacts of externalities in planning for site-specific developments; it also accounts for systematic impacts off site, and impacts to combined human-environmental systems for food, water, waste, energy, and shelter. The many definitions of sustainability all embody common the concepts of "stewardship", "design with nature," plus incorporate recent concepts of the "precautionary principle", and "carrying capacity". Sustainability science uses the wisdom from multiple disciplines in decision-making (e.g. it is "transdisciplinary"). In aquaculture, it is used to undertake more comprehensive planning for multiple impacts on multiple time and spatial scales to better understand and plan for the consequences of development options.
The emerging fields of ecological aquaculture [2,3] and agroecology [7,8] recognize that the implementation of more sustainable food production systems require knowledge about how ecosystems are utilized and how conflicts among social groups are addressed. A baseline of response to social ecological changes is the foundation for the implementation of more sustainable food systems, and the practice of adaptive management must be included as responses to changes in the condition of ecosystems in which new food production is conducted requires incorporation of an iterative learning process.
The use of sustainability science in aquaculture marks the path toward encouraging a long-term perspective and an appreciation of the roles played not only by ecologists, but also by civil societies, markets, and governments in adapting to food systems and ecosystems changes. The use of sustainability science in aquaculture is an approach that is fundamentally a knowledgebased enterprise that incorporates baseline information on natural and human ecosystems, then develops, evaluates, encourages, and communicates imagination, ingenuity, and innovation at both the individual and institutional levels [9].
This information is designed for use by teams of aquaculture professionals working to apply the principles of ecosystem-based management. Information obtained is typically cross sectoral as interdisciplinary groups are needed that are educated in such diverse fields as the natural and social sciences, law, and business. Applying the notions of sustainability science in aquaculture is intended to inspire engagement of governmental agencies, businesses, non-governmental groups and academics to achieve the highest form of sustainable development in any known protein production food system by using the concepts of ecological design and through the many forms of stewardship. At present, there is a paucity of information targeted specifically for those engaged in aquaculture programs and projects in places where the ability of government to regulate and direct the processes of ecosystem change is weak or severely constrained.
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