Digital library

  • Kappaphycus and Eucheuma species have been successfully cultivated in Southeast Asia since the early 1970s. The increasing global demand for carrageenan in processed foods and thereby the need for industrial-scales of biomass to be provided to feed an extraction industry, exceeded wild stock availability and productivity and commercial demands could only be achieved through extensive cultivation of selected carrageenophytes. This unprecedented situation led to the introduction of carrageenophyte species and cultivars around the world; combined production of Eucheuma and Kappaphycus is one of the largest for seaweed biomass in the world.

     

    The activity of, and economic benefits accrued from, seaweed farming are indeed responsible for significant changes in rural, coastal communities in a number of important countries. Such activities generating new activity and income are often the only source of cash to some of the farmers. However, in spite of the enormous size and value of the industry the techniques applied to cultivation of carrageenophytes has remained almost unchanged in the commercial farms. Seedlings (or vegetatively propagated fragments of older, larger, mature thalli) are still most commonly planted along ropes held in various configurations, in most of the major production centers, e.g. mostly classified as simple stakes in the ground (off-bottom planting to floating rafts of various design). Some technological developments have been made in Brazil and India with the implementation of tubular nets for planting, which allows a degree of mechanization on the farms; both countries are developing mechanical harvesters. Further to co-production of biomass and harvesting, the drying process is still a limiting problem for production, and drying costs are high, in countries with high rainfall, this segment of the process is discussed in detail by Ali et al. Chap. 8). Diseases such as “ice-ice” and blooms of epiphytes and endophytes (see Chap. 6 by Loureiro et al.), as well as present and impending climate change effects (see Chap. 7 by Largo et al.) are also very big challenges.

    In general, the production of carrageenophytes in tropical and sub-tropical regions is very dependent on the weather: as in prevailing conditions during the dry and wet seasons or surface seawater temperatures (SSTs) during “cold” winters and/or “hot” summers. For the future, efforts need to be made to increase the productivity and resistance of the selected strains of carrageenophyte seedlings against environmental instabilities.

    Author(s): Leila Hayashi, Renata P. Reis, Alex Alves dos Santos, Beatriz Castelar, Daniel Robledo, Gloria Batista de Vega, Flower E. Msuya, K. Eswaran, Suhaimi Md. Yasir, Majid Khan Majahar Ali, Anicia Q. Hurtado
  • The aim of this study was to determine the impact of sea urchin grazing ( Echinus esculentus) and canopy shading on the recruitment of the kelp Laminaria hyperborea in mid-Norway. A spatially variable distribution of sea urchins was observed, and recruitment processes were studied both after disturbance, caused by kelp harvesting removal of the canopy kelps, and in pristine kelp forests. The combination of sea urchin density and the density of canopy-forming kelps had the strongest influence on the density of small kelps in pristine kelp forest, suggesting that both grazing from sea urchins and shading from the canopy contributed to the mortality of small kelps. High densities of small kelps ( > 20 m(-2)) were only found in pristine kelp forest together with <= 6 canopy-forming kelps m(-2) or < 3 sea urchins m(-2) on average. However, within the observed range of sea urchin densities these had no effect on the density of large, canopy-forming kelps. Large L. hyperborea were apparently not subject to grazing. In addition, only a small number of surviving kelp recruits was needed to maintain the density of canopy-forming kelps, as L. hyperborea specimens may survive many years. These conditions result in high stability of the kelp forest. A different picture was seen after kelp harvesting, when high recruitment and survival of recruits are the conditions for rapid restoration of the kelp vegetation. After removal of the canopy-forming plants, the kelp recruits were temporarily released from high density-dependent mortality due to shading. Some influence of sea urchin grazing on the density of recruits was observed, but this was small compared with the strong canopy effect. However, the accumulated impact of grazing during a period of time had a strong overall effect on the regrowth of kelp. After 2.5 years the accumulated biomasses at the harvested stations were strongly related to average sea urchin density, and a density of between 4 and 5 sea urchins m(-2) resulted in very little biomass accumulation. This suggests that the L. hyperborea kelp forest vegetation has a high degree of stability, but shows less resilience after disturbance, when exposed to moderate sea urchin grazing.

    Author(s): Kjersti Sjøtun, H. Christie, Jan Helge Fosså
  • The wholesale price of farmed salmon in local fish markets showed higher prices before the tsunami in 2011. Though farmed coho salmon started being landed again by the support of national funding in 2012, the price of the farmed salmon slumped. A higher price is necessary to maintain the farming facilities for management. This paper aims to clarify the causes of the price drop of Sanriku coho salmon and the issues in the reconstruction process of coho salmon aquaculture. The most important cause of the price drop of Sanriku coho salmon was that consumersʼ purchasing patterns changed from Sanriku coho salmon to imported salmon due to the lack of Sanriku coho salmon in 2011. We hope to supply fresh Sanriku coho salmon at prices between imported fresh Atlantic salmon and frozen rainbow trout in consumer markets. It is necessary to improve the traditional aquaculture system and to develop brand value for Sanriku coho salmon. Sales promotion is expected to drive the price of the fresh coho salmon up to a fair level.

    Author(s): Kohichi SAOTOME, Hideki MIURA, Tsuyoshi TANAKA, Ikutaro SHIMIZU
  • Meat consumption is rising worldwide, but production involves vast amounts of energy, water and emissions. At the same time, wild fisheries are declining. Aquaculture could become the most sustainable source of protein for humans.Fish farming already accounts for half of global seafood production. Most of it is done along coastlines, which creates substantial water pollution.

    Large, offshore pens that are anchored to the sea floor are often cleaner. Those farms, other new forms of aquaculture, and practices that clean up coastal operations could expand aquaculture significantly. Questions remain about how sustainable and cost-effective the approaches can be.

     

    Author(s): Sarah Simpson
  • Modern methods of food production have accelerated climate change, but can sustainable practices aid in reversing it? The Architecture of Aquaculture seeks to explore the restorative effects of seaweed aquaculture through an adaptive reuse of British Columbia’s controversial salmon farms. The Architecture of Aquaculture examines the role seaweed aquaculture can play in mediating climate challenges through the development of a new building typology that utilizes program and built form to articulate the relationship between humans, the built environment, and nature. The following chapters emphasize seaweed’s importance along British Columbia’s West Coast, and the positive environmental effects it can have on the land, sky and, sea. The final design proposes an adaptive reuse of 19 salmon farms within British Columbia’s Discovery Islands and Powell River.

    Author(s): Micaelee Hanson
  • The goal of this study was to evaluate flow-cytometric techniques for isolating individual kelp meiospores into 96-welled plates. Previously reported low success rates for sorting tens of thousands of meiospores at a time have been improved by technological developments, specifically, the low nozzle pressure of the commercially available, JSAN (Bay Bioscience Co. Ltd) instrument. We monitored growth and gametophyte development post-sorting for 10 months. Our data demonstrate that successful kelp meiospore isolations of up to 76% viability can be achieved with flow-cytometry. This method can save time as compared to traditional, manual isolations using pipettes and improves confidence that self-fertilized individuals will not contaminate specific crosses of resulting gametophytes. Our results highlight a new application for the flow cytometer to produce clonal kelp gametophytes with direct applications for germplasm and culture collection development.

    Author(s): Yarish, Charles Simona Augyte, Gary H. Wikfors, Steve Pitchford, Michael Marty-Rivera, Schery Umanzor, Scott Lindell, David Bailey
  • The 23rd International Seaweed Symposium (ISS) was held in Jeju, Republic of Korea, on April 28 to May 3, 2019, at the International Convention Centre. The ISS is a triannual congress held under the auspices of the International Seaweed Association (ISA; www.ISASeaweed.org). Starting from humble beginnings in 1952 with the First International Seaweed Symposium in Edinburgh, Scotland, with Dr. F.N. Woodward as chairman (Indergaard 2017), we are now almost 7 decades further with the 23rd Symposium in Korea. In 1952, almost 200 people attended from 21 different countries, and 53 papers were submitted; we now have peaked at over 850 registrants from 41 different countries, 22 mini symposia, 349 oral presentations, and 259 poster presentations (Fig. 1). During the last decade, seaweeds in general have become very popular as they have such a wide and diverse application from raw material and aquaculture/IMTA to fertiliser and biostimulants, feed and animal health, food and human health to materials, fabric, pharma, biotechnology and carbon sequestration/ habitat restauration (Fig. 2). Coupling this to the Korea’s long history and tradition of seaweed aquaculture and food use and the 23rd ISS was guaranteed to become a success. We are also happy to report that the exhibition/trade show is a growing part of the ISS which became very apparent at the Korean congress demonstrating the wide variety of seaweed use in everyday life. The link with the seaweed industry is of vital importance to the ISS concept and stimulates synergy and partnerships between academics and industry and provides vital important funding to be able to run these conferences.

    Author(s): Stefan Kraan, Susan Løvstad Holdt, Jeong Ha Kim
  • Sea purslane Halimione portulacoides (L.) Aellen is a candidate extractive species for coastal Integrated Multi-Trophic Aquaculture (IMTA) to recycle the dissolved inorganic nitrogen (DIN) and phosphorus (DIP) wasted by excretive species. To test its suitability, saline aquaculture effluents were simulated in the laboratory using a hydroponics approach to cultivate the plants. Nutrient extraction efficiency, growth performance and nutritional profile were assessed under a range of DIN and DIP concentrations representing three different aquaculture intensification regimes and using Hoagland's solution as a control. Over a 10-week period, hydroponic units under non-limited N and P conditions displayed daily extraction rates between 1.5 and 2.8 mg DIN-N L-1 day-1 and 0.1-0.2 mg DIP-P L-1 day-1 and yielded between 63.0 and 73.0 g m-2 day-1 of H. portulacoides biomass. Relatively to biomass produced, H. portulacoides extracted between 2.6 and 4.2 mg DIN-N g-1 and 0.1-0.4 mg DIP-P g-1. The treatment with low-input of DIN and DIP (6.4 mg N L-1 and 0.7 mg P L-1) induced some degree of nutrient limitation, as suggested by the extremely high extraction efficiencies of DIN extraction (99%) in parallel with lower productivity. The nutritional profile of H. portulacoides leaves is comparable to that of other edible halophytes and leafy greens and could be a low-sodium alternative to salt in its lyophilized form. From the present study, we conclude that the edible halophyte H. portulacoides can be highly productive in hydroponics using saline water irrigation with non-limiting concentrations of DIN and DIP and is, therefore, a suitable extractive species for coastal IMTA in brackish waters.

    Author(s): Ana I. Lillebø, Ricardo Calado, Sebastián Villasante, Marco Custódio
  • Saccharina sculpera is highly valued for human consumption and value-added products. However, natural resources of this kelp have decreased sharply and it is in danger of extinction. Resources recovery through cultivation is being trialed to enable the sustainable use of this species. In this study, the temperature range for survival and optimal growth of juvenile S. sculpera was identified and applied to field cultivation. This study investigated the survival and growth of juvenile S. sculpera under six temperatures (i.e., 5, 10, 15, 16, 18, and 20°C) and two light intensities (i.e., 20 and 40 µmol photons m-2 s-1) in an indoor culture experiment. In these experiments, the blade length decreased at 16°C under the both light intensities. The thalli died at 20°C and 20 µmol photons m-2 s-1, and at 18‒20°C and 40 µmol photons m-2 s-1. During the field cultivation, early growth of S. sculpera was highest at the 5 m depth and growth decreased as the water depth increased. When the initial rearing depth was maintained without adjustment throughout the cultivation period (from December to October), all the cultivated S. sculpera plants died during August and September. However, S. sculpera plants lowered from 5 to 15 m and grew to 90.8 ± 13.1 cm in July. The seawater temperature at 15 m depth was similar to the upper level of thermal tolerance demonstrated by juvenile S. sculpera in the indoor culture experiments (16°C or lower). The plants were subsequently lowered to 25 m depth in August, which eventually led to their maturation in October. The present study confirmed that improved growth rates and a delay in biomass loss can be achieved by adjusting the depth at which the seaweeds are grown during the cultivation period. These results will contribute to the establishment of sustainable cultivation systems for S. sculpera.

    Author(s): Soo Hong Kim, Young Dae Kim, Mi Sook Hwang, Eun Kyoung Hwang, Hyun Il Yoo
  • Saccharina latissima is an economically and ecologically relevant kelp species in Europe and North America. In kelps, the sexuality is expressed during the haploid life stage and the microscopic gametophytes exhibit significant sexual dimorphism. To understand the sex-dependent impact of temperature on the gametophyte stage, we analyzed for the first time, gene expression profiles of male and female gametophytes at three different temperatures (4, 12, and 20°C) characteristic for the species distribution range by using RNA-sequencing. We identified several differentially expressed genes (DEGs) between sexes; while female biased genes were enriched in general metabolism and energy production, male biased genes function within cell cycle and signaling. In our study, temperature modulated sex-biased gene expression, with only a small percentage of DEGs consistently male (7%) or female-biased (12%) at the three temperatures. Female gametophytes responded stronger to higher temperatures than males, suggesting that males are more heat tolerant. Differences between S. latissima and other brown algal gender-dependent gene expression might mirror the different evolutionary and ecological contexts. Genomic information on kelp gametophyte is still scarce and thus this study adds to our knowledge on sex differences in abiotic stress responses in macroalgae at the transcriptomic level.
    … 
     
    Author(s): Cátia Monteiro, Sandra Heinrich, Inka Bartsch, Klaus Valentin, Erwan Corre, Jonas Collén, Lars Harms, Gernot Glöckner, Kai Bischof

Pages