Key questions that will determine the future prospects for open ocean aquaculture (OOA) are the attitude of government, the technology that is developed to enable development, and the market for seafood products.
Digital library
-
-
Agar is produced on commercial scale from August, 1999 onwards in the Agar Plant at Re,gional Centre of Central Marine Fisheries Research Institute, Mandapam C;unp using the red seaweed Graci/aria edulis (Kanji Pasi) as raw material. Agar is manufactured in sheet fonn by washing the dried seaweed in the ~gitator tank, treating with Hc1, cooking in the digester by passing steam, collecting the agar gel in aluminium trays, freezing the gel in freezing unit, thawing, bleaching and sun-drying of agar sheets. The yield of agar is found to be 6 to 8%. The gel strength, gelling and melting temperature of 1.5% agar ranged from 74 to 122 gicm', 44 to 46"C and 95 to 97"C respectively. The bleacbed agar sheets are marketed by packing them in polythene bags. The methods for improving the yield and quality of agar are suggested.
-
Carrageenan is one of the commercially important water soluble polysaccharides extracted from certain red algae and it is widely utilised in foods, dairy products and pharmaceuticals. In India, there is no carrageenan manufacturing unit and knowledge on the processing technologies of this phytochemical is very limited. Various methods available for the extraction of different types of carrageenan are reviewed in this paper.
-
The seaweeds are the only source for agar and algin. They are also used as food material, livestock feed and fertilizer in many parts of the world. The various products obtained from Indian seaweeds and their uses are dealt with here.
-
1. QAPP development. 2. Calculate N load estimates for a minimum of 50 embayments using a published model which relates land-use in the watershed to the total N load for the embayment. 3. Calculate estimates of the freshwater flushing time for a minimum of 50 embayments using two methods: (1) a modified tidal prism method and (2) a simplified method developed in embayments which relate estuarine length and surface area to freshwater flushing time. 4. Using the output from Objectives 1 & 2, a published model will be used to estimate the dissolved inorganic nitrogen (DIN) concentration in the embayments. This value will be used to quantify the error of the model outputs predicting N load. 5. Field-based evaluation of ten embayments in New York (NY) and Connecticut (CT) for susceptibility to hypoxia and primary producer community composition. 6. Apply field data to indices developed to identify the trophic status of estuaries. We will use two methods: one developed by the EPA and one developed by NOAA. 7. Develop a statistical model using multivariate analysis techniques to relate the calculated N load (#2), fresh water flushing time (#3), and estuarine trophic status (#6). Develop predictions as to which of the unsampled LIS embayments are most likely to experience symptoms of eutrophication. 8. Using the predictions of eutrophication risk for 50 embayments (#7), develop "report cards" for each embayment detailing potential environmental issues and the likeliest causes. These report cards will be presented to the LISS STAC, community groups and other groups who provided data, NY Sea Grant, CT Sea Grant, Citizen's Campaign for the Environment (CT and NY) and Save the Sound / CT Fund for the Environment.
-
Our team has initiated a selective breeding program forregional strains of sugar kelp,Saccharina latissima, toimprove the competitiveness of kelp farming in the UnitedStates. Within our breeding program, we also include anendemic putative species,Saccharina angustissima, locallyreferred to as skinny kelp. We crossed uniclonal gameto-phyte cultures derived from 37 wild-collected blades rep-resenting five sugar kelp strains and one skinny kelp strainto produce 104 unique crosses. Each cross was outplantedon a near-shore research farm located in the Gulf of Maine(GOM). After the first farming season, our results indicatedthat sugar kelp and skinny kelp were interfertile, and pro-duced mature and reproductively viable sporophytes. Mor-phological traits of individual blades varied depending onthe parental contribution (sugar vs. skinny), with significantdifferences found in progeny blade length, width, thickness,and in stipe length and diameter. Despite these differences,wet weight and blade density per plot showed no statisticaldifferences regardless of the cross. Given their publishedgenetic similarity and their interfertility shown here,S. angustissimaandS. latissimamay not be different species, and may each contribute genetic diversity to breeding pro-grams aimed at meeting ocean farming and market needs.
-
Laminaran, porphyran, and ulvan are major seaweed polysaccharides in brown, red, and green algae, respec- tively. We compared their prebiotic effects using individual microbial fermentability test and in vitro fecal fer- mentation. The fermentability test showed that these polysaccharides were selectively utilized by Bifidobacteria, Lactobacilli, and Bacteroides (ΔOD580 nm, 0.2–1.0), while no growth of harmful bacteria was observed. In vitro fecal fermentation for 24h showed growth stimulation effect of laminaran on Bifidobacteria (Δ8.3%/total bacteria) and Bacteroides (Δ13.8%/total bacteria) promoting the production of acetate and propionate. Ulvan exhibited same result on Bifidobacteria (Δ8.5%/total bacteria) and Lactobacillus (Δ6.8%/total bacteria) pro- moting the production of lactate and acetate; however, porphyran showed little prebiotic effect. Laminaran was fermented slowly compared to fructooligosaccharides and this may permit production of short-chain fatty acids in distal colon. This in vitro study demonstrates that the seaweed polysaccharides tested, particularly laminaran and ulvan, have prebiotic effects on microbiota in human colon.
-
Macroalgal blooms are ecological responses to nutrient enrichment in shallow seagrass-dominated estuaries. For decades the Indian River Lagoon (IRL) a biodiverse estuary in east-central Florida, has experienced persistent blooms of red drift macroalgae, including Gracilaria and Hypnea spp. Since 2013, extensive blooms of green macroalgae, such as Chaetomorpha and Ulva spp., have developed. To better understand IRL nutrient effects on bloom-forming macroalgae, field and laboratory studies (2012) assessed nitrogen (N) versus phosphorus (P) limitation and morphological/physiological characteristics in relatively urbanized (Titusville, FL) versus rural (Fort Pierce, FL) IRL segments. Field studies indicated Ulva lactuca, Hypnea musciformis, and Gracilaria tikvahiae all grew fastest in Titusville (average ± SD; 0.49 ± 0.07, 0.35 ± 0.03, and 0.14 ± 0.05 doublings d−1, respectively). However, U. lactuca had the most rapid biomass doubling time (2 days). Laboratory nutrient en- richment assays revealed 3-fold increases in rapid light curve (RLC) maximum values and 2-fold faster growth at high concentrations of N and P for U. lactuca. This superior growth and photosynthesis was attributed to higher surface area:volume ratios averaging (± coefficients of variation, %) 565.2 ± 2.15 cm2 g dry wt.− 1 compared to lower ratios for H. musciformis (110.7 ± 3.97 cm2 g dry wt.−1) and G. tikvahiae (91.1 ± 1.81 cm2 g dry wt.−1). Finely- and coarsely-branched H. musciformis and G. tikvahiae were similar photosynthetically but not morpho- logically based on a functional/form model. These data provide a physiological basis explaining bloom distribu- tions and the recent success of green macroalgae in the increasingly eutrophic IRL.
-
Pulse amplitude modulation (PAM) fluorometry is ideally suited to measure the sub-lethal impacts of photosystem II (PSII)-inhibiting herbicides on microalgae, but key relationships between effective quan- tum yield [Y(II)] and the traditional endpoints growth rate (l) and biomass increase are unknown. The effects of three PSII–inhibiting herbicides; diuron, hexazinone and atrazine, were examined on two trop- ical benthic microalgae; Navicula sp. (Heterokontophyta) and Nephroselmis pyriformis (Chlorophyta). The relationships between Y(II), l and biomass increase were consistent (r2 P 0.90) and linear (1:1), validat- ing the utility of PAM fluorometry as a rapid and reliable technique to measure sub-lethal toxicity thresh- olds of PSII-inhibiting herbicides in these microalgae. The order of toxicity (EC50 range) was: diuron (16–33nM)>hexazinone (25–110nM)>atrazine (130–620nm) for both algal species. Growth rate and photosynthesis were affected at diuron concentrations that have been detected in coastal areas of the Great Barrier Reef.
-
Environmental concerns regarding natural resource depletion have led to the cultivation of more renewable resources such as seaweed biomass. As the cultivation in Europe is still in its early stages, an estimation of the environmental sustainability may boost further development of this sector by highlighting its competitiveness. A case study on the resource footprint of Saccharina latissima production near the West coast of Ireland (18 ha of floating longlines) and France (0.6 ha of raft systems) is performed. The Cumulative Exergy Extraction from the Natural Environment (CEENE) method is used to quantify the exergy deprived from 8 types of natural resources (incl. marine resources) to produce 1 MJ ex biomass. For Ireland and France, results of the Exergetic Life Cycle Assessment (ELCA) are 1.7 MJ ex MJ ex −1 and 8.7 MJ ex MJ ex −1 , respectively. Compared to the footprint of microalgae and several terrestrial plants (sugar beets, maize and potatoes), typically showing values in the range of 0.92–3.88 MJ ex MJ ex −1 , seaweed production in North West Europe (especially in Ireland) is relatively resource-efficient. Moreover, the potential to improve the resource footprint of seaweed production is investigated; in the short-term, seaweed can be cultivated with a comparable life cycle resource demand as several land plants.
Pages
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.