The United States has a small net-pen salmon industry dating back over 40 years and a nascent net-pen industry for other marine fish. The United States net-pen aquaculture sector has improved its resource efficiency in terms of the amount of fish meal and fish oil used in feeds and reduced its environmental impacts in terms of the mass loading and impact of nutrient discharge on the receiving ecosystem, the incidence and treatment of fish diseases, the use of antibiotics, and the number and impact of fish escapes, while increasing production. These changes can be attributed to a combination of advances in science and technology, rising cost of fish meal/oil, improved management, and informed regulatory practices. Net-pen aquaculture has become an efficient food production system. Existing laws and regulations in the United States effectively address most of the potential adverse environmental effects of net-pen aquaculture.
Digital library
-
-
Concern for possible environmental damage constrains development of the aquaculture
industry in the United States. Potential environmental interactions, including degradation
of water quality, introduction of exotic species, pollution of the seafloor, adverse interaction
with the seafloor benthic community, adverse interactions with protected species, and genetic interactions of potential escapees are all generally viewed as negative interactions, and thus are of substantial concern to the public and to regulators. Certainly, the culture of finfish in cages can be detrimental to the local water quality and the benthos beneath the cages when the fish are overfed or when too many production units are located in an area of limited carrying capacity or restricted circulation, as has been demonstrated by numerous published reports (see Black 2001 for a summary). -
The central objective of this paper is to evaluate the production of biogas by the substitution of energy crops with marine macroalgae: mixture of brown (20%) and red algae (80%) as feedstock in an industrial scale biogas plant. This plant operates with the co-digestion of maize (27%), grass (54%), rye (8%) and chicken manure (11) and produces 500 kWh energy. In order to assess environmental friendliness, a life cycle assessment was performed by using the software Simapro. Potential environmental impact categories under investigation were global warming, acidification, eutrophication and land transformation potential. Our results determine the affirmative impact of the codigestion of algae with chicken manure on the emission reductions: 52%, 83%, 41% and 8% lower global warming, acidification, eutrophication and land transformation potentials, respectively per 1 MJ of energy generation, moreover, 84% and 6% lower acidification and land transformation potentials per kg of feedstock.
-
Seaweeds are multicellular algae that occur in marine and brackish-water and that, at some stage in their lives, are attached to a substrate. World-wide there are approximately 10,000 species of seaweeds and at least 221 species of seaweed are utilised by humans. 145 species are used for food while 101 species are used for phycocolloid production (i.e. alginates, agar and carrageenan). Each year around 2 million tonnes dry weight (approximately 13 million tonnes fresh weight) of seaweed is collected at a value of in excess of US$6.2 billion. 50% of this seaweed (by volume) is cultured and approximately 10% of cultured seaweed comes originates in the tropics. In the tropics the vast majority of seaweed farmed is of the genera Eucheuma or Kappaphycus. Approximately 120,000 tonnes dry weight (t dw) of Eucheuma/Kappaphycus are produced annually compared with approximately 15,500 t dw of Gracilaria and 800 t dw of Caulerpa (Zemke-White and Ohno 1999). Most of the Eucheuma/Kappaphucus is farmed in the Philippines (~95,000 t dw), followed by Indonesia (22,000 t dw), Zanzibar (4,000 t dw), Malaysia (800 t dw), Kiribati and Madagascar (both around 400 t dw). Most of the Gracilaria is farmed in Indonesia (~13,500 t dw) and almost all of the Caulerpa is farmed in the Philippines.
-
As the demand for proteins increases with growing populations, farmed seaweed is a potential option for use directly as an ingredient for food, feed, or other applications, as it does not require agricultural areas. In this study, a life cycle assessment was utilised to calculate the environmental performance and evaluate possible improvements of the entire value chain from production of sugar kelp seedings to extracted protein. The impacts of both technical- and biological factors on the environmental outcomes were examined, and sensitivity and uncertainty analyses were conducted to analyse the impact of the uncertainty of the input variables on the variance of the environmental impact results of seaweed protein production. The current production of seaweed protein was found to have a global warming potential (GWP) that is four times higher than that of soy protein from Brazil. Further, of the 23 scenarios modelled, two resulted in lower GWPs and energy consumption per kg of seaweed protein relative to soy protein. These results present possibilities for improving the environmental impact of seaweed protein production. The most important variables for producing seaweed protein with low environmental impact are the source of drying energy for seaweed, followed by a high protein content in the dry matter, and a high dry matter in the harvested seaweed. In the two best scenarios modelled in this study, the dry matter content was 20% and the protein content 19.2% and 24.3% in dry matter. This resulted in a lower environmental impact for seaweed protein production than that of soy protein from Brazil. These scenarios should be the basis for a more environmental protein production in the future.
-
An exploratory Life Cycle Assessment (LCA) was carried out to provide insight into the environmental impacts of using the green seaweed Ulva spp. as a feedstock, for production of bioplastic. The study focused on the production of lactic acid as a precursor of polylactic acid. The study was on the production process: (1) The cultivation of Ulva spp., in an Integrated Multitrophic Aquaculture system; (2) the processing of the biomass for solubilization of sugars; (3) the fermentation of the sugars to lactic acid; (4) the isolation of lactic acid from fermentation broth. The study identified environmental hotspots and compared an experimental seaweed production chain with conventional feedstocks. The main hotspot is derived from electricity consumption during seaweed cultivation. The impact of electricity consumption can be lowered by reducing energy use and sourcing renewable energy, and by improving the material efficiency in the product chain. To improve understanding of the process of production’s environmental impacts, future studies should broaden the system boundaries and scope of sustainability issues included in the environmental assessment.
-
Seaweeds are a potential source of bioactive compounds that are useful for biotechnological applications and can be employed in different industrial areas in order to replace synthetic compounds with components of natural origin. Diverse studies demonstrate that there is a solid ground for the exploitation of seaweed bioactive compounds in order to prevent illness and to ensure a better and healthier lifestyle. Among the bioactive algal molecules, phenolic compounds are produced as secondary metabolites with beneficial effects on plants, and also on human beings and animals, due to their inherent bioactive properties, which exert antioxidant, antiviral, and antimicrobial activities. The use of phenolic compounds in pharmaceutical, nutraceutical, cosmetics, and food industries may provide outcomes that could enhance human health. Through the production of healthy foods and natural drugs, bioactive compounds from seaweeds can help with the treatment of human diseases. This review aims to highlight the importance of phenolic compounds from seaweeds, the scope of their production in nature and the impact that these compounds can have on human and animal health through nutraceutical and pharmaceutical products.
-
The present investigation indicates that G. edulis can be successfully cultivated on commercial scale in the nearshore areas of Gulf of Mannar during the five months period from November to March when the sea is calm. The shallow waters near CMFRI fish farm in Palk Bay are not suitable for G. edulis cultivation as the growth of the plant was affected by various environmental factors mentioned above. The culture experiments of G. edulis conducted earlier by the Central Marine Fisheries Research Institute in 3 - 4 m depth area at Palk Bay near CMFRI fish farm showed good growth of plants as there was less sedimentation, fouling organisms and predators. Hence G. edulis could be cultivated in deep waters in Palk Bay side and attempts may also be made to culture G. edulis in shallow waters at other areas of Palk Bay in order to select the suitable culture sites and period of good growth.
-
We quantified the effects of temperature, light and nitrogen availability on the growth and fatty acids (FAs) in three isolates of the green seaweed Derbesia tenuissima to portion the environmental and the genotypic (between isolates) components of variation. Growth ranged from 13 to 33% day−1 and 27% of the variation was between isolates and 48% of variation was explained by light intensity. The content of total FA (TFA) ranged from 34 to 55 mg g−1 dw and 49% of the variation was between isolates, while the TFA was 20% lower in the high light and low nitrogen treatment combination. The proportion of omega-3 polyunsaturated FA (PUFA(n-3)) ranged from 31 to 46% of TFA with a strong interactive effect of isolate and temperature. In two isolates, the proportion of PUFA(n-3) increased by 20% under cultivation at low temperature while in a third isolate temperature had no effect. Increases in PUFA(n-3) occurred with a stable content of TFA and high growth rates, leading to net increases in PUFA(n-3) productivity in two isolates. This research highlights the potential for environmental manipulation and strain selection to further improve the productivity and quality of fatty acids in seaweed.
-
The consequent reduction of land resources by human activities such as pollution, over exploitation, industrialization, migration etc., has lead man to search for other alternative ways to meet the demands for well-being. When this has been the existing situation in most of the developing countries, kelp forest resources like seaweeds which are known for its potentially strong bioactive compounds can be the best fit to fulfill numerous requirements such as nutritious food, biofuels, biofertilizer and pharmaceuticals to cure different diseases and other industrial applications. From the history till date seaweed has been employed in various sectors like food, pharmaceuticals, agriculture, waste water treatment and so on. Malnutrition and poverty have become the major issue in many of the developing nations, hale and healthy life can be guaranteed by seaweed food products and also people can be self- employed. Besides many research works done regarding seaweeds this review provides a collective idea about the potentials and wide range applications of seaweed, a marine macroalgae.
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.