The marine aquaculture sector is growing rapidly. Offshore aquaculture installations have been drawing increasing attention from researchers, industry and policy makers as a promising opportunity for large-scale expansion of the aquaculture industry. Simultaneously, there has also been increased interest in both land- based and nearshore aquaculture systems which combine fed aquaculture species (e.g. finfish), with inorganic extractive aquaculture species (e.g. seaweeds) and organic extractive species (e.g. suspension- and deposit-feeders) cultivated in proximity. Such systems, described as integrated multi-trophic aquaculture (IMTA), should increase significantly the sustainability of aquaculture, based on a number of potential economic, societal and environmental benefits, including the recycling of waste nutrients from higher trophic-level species into production of lower trophic-level crops of commercial value. Several of the challenges facing IMTA in nearshore environments, are also relevant for offshore aquaculture; moreover, the exposed nature of the open ocean adds a number of technical and economic challenges. A variety of technologies have been developed to deal with these constraints in offshore environments, but there remains a number of challenges in designing farm sites that will allow extractive species (e.g. seaweeds and shellfish) to be integrated in fed aquaculture systems and be able to withstand the strong drag forces of open oceans. The development of offshore IMTA requires the identification of environmental and economic risks and benefits of such large-scale systems, compared with similarly-scaled monocultures of high trophic-level finfish in offshore systems. The internalizing of economic, societal and environmental costs of finfish monoculture production by the bioremediative services of extractive species in IMTA offshore systems should also be examined and analyzed. The results of such investigations will help determine the practical value of adopting the IMTA approach as a strategy for the development of offshore aquaculture.
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Conventional biomass sources have been widely exploited for several end uses (mostly food, feed, fuel and chemicals). More unconventional sources are continually being sought for meeting the growing planetary demands for biomass materials. Biofuels are already commercially produced in many countries and are becoming mainstream. The role of biorefineries for production of chemicals is also on the rise. Plant biomass is the primary source of food for all multicellular living organisms. Primary production remains a key link in the chain of life support on planet Earth. Is there enough for all? What new strategies (or technologies) are available or promising for providing plant biomass in a safe and sustainable way? What are the potential impacts (footprints and efficiencies) of such strategies? What can be the limiting factors—land, water, energy and nutrients? What might be the limits for specific regions (OECD vs. non-OECD, advanced vs. developing, dry and warm vs. wet and cool, etc.). In this paper, we provided answers to these questions by critically reviewing the pros and cons associated with current and future production and use pathways for biomass. We conclude that in many cases, the jury is still out, and we cannot come to a solid verdict about the future of biomass production and use.
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A great deal of information is available on tbe fauna associated witb seaweeds of temperate waters (Wieser, 1952 for review; Cbapman.1955; Soutbward, 1958; Wieser, 1959; Sloane el. af., 1961; Fuse, 1962; Me Lean, 1962; Ledoyer, 1962, 1964, 1966; Obm. 1964; Glynn, 1965; Hagerman. 1966; Moore, 1971; Alcala el af., 1972: Mallav ... a, 1976). There are many scattered references to tbe associations of animals to marine algae from tbe Indian coasts. However, in depth studies on tbe nature of relationsbips, distribution and abundance of animal populations on seaweeds are lacking except for a few recent studios (Josepb, 1972; Sarma and Ganapati, 1972; Sanna, 1974). The present study was undertaken during 1968-71 to ascertain tbe species composition, feeding bablts and inter-relationsbips in tbe dominant groups of animal. associated with economic seaweeds of South India
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Quantitative studies are of great value in ecological investigations as the numerical, volumeteric or gravimetric estimation, of the populations provide estimates of productivity and standing crop and enable numbers and weight, of animals in a given habitat to be compared both in time and in space. Colman (1940) was the first to estimate the numerical abundance of the fauna inhabiting intertidal sea weeds. Later, many attempts have been made by various workers (Wieser, 1952, 1959; Chapman, 1955; Glynn, 1965; Hagerman, 1966; Jansson, 1967; Moore, 1971) to study the algal communities in the temperate waters. From the Indian coasts, the only study of similar nature is by Sarma and Ganapati (1972) who studied the numerical distribution of phytal fauna on 13 species of seaweeds from the intertidal regions of Visakhapatnam coast. The spatial and temporal distribution of the macrofauna inhabiting intertidal seaweeds at Mandapam Camp is discussed in this paper.
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The importance of algivorous animals in the ecology of economic seaweeds has been recognised by many workers (Tilden, 1927; Leighton, 1960; Chapman, 1962; North, 1962, 1963; Boney. 1966). In recent years many studies have been made to ascertain the food and feeding habits of major algivores, the important among which are by Barkman ( 1955), van Dongen (1956), Bakker (1959), Satio and Nakamura (1961). Leighton and Boolootian (1963), Leighton (1966), Paine (1963) and Paine and Vadas (1969). In order to study the role of algivores in the ecology of cultivatable marine algae and to ascertain the nature of discri_ mination in the choice of algal food by them, a study was undertaken during 1968- '71 at tbe Marine Algal Researcb Station, Mandapam. This paper presents tbe findings pertaining to the cbief algivorous gastropods in tbe Gulf of Mannar and Palk Bay region.
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Decomposition in terrestrial and aquatic environments of biogenic or synthetic organic material to inorganic products (also referred to as ‘mineralization’) is predominantly accomplished by microbial oxidations. Under anaerobic conditions, protons, sulfur or carbon atoms are the exclusive electron sinks, products being H2, H2S or CH4 respectively. In this last case, the hydrogénation of CO2 to CH4 or the protonation of the methyl group in acetate (or methylamins) to CH4 are the final reactions:
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The potential economic impact of a fully developed mariculture industry in Alaska is not well understood by industry or policymakers. It is also not entirely clear what is needed to move from Alaska’s current micro industry to a fully developed industry. The Alaska Fisheries Development Foundation (AFDF) has been awarded a grant from NOAA in order to spearhead the Alaska Mariculture Initiative (AMI) with the following goals: (1) expand the stakeholder base, create partnerships, and increase capacity to be effective; and (2) develop a clear and comprehensive strategic plan, including a written commitment to implement the plan by the various stakeholders and agencies. Northern Economics, Inc. was contracted by AFDF to conduct an economic analysis to help inform decisions to be made in the creation of the AMI strategic plan. The economic analysis will contain three phases:
- Phase I: Comparative case studies which outline examples of successful mariculture industries in different regions of the world
- Phase II: Preliminary economic analysis to support the development of a statewide strategic plan
- Phase III: Analysis of the costs, benefits, and economic impact of the statewide strategic plan developed as part of the AMI
This report represents the work completed for Phase 1. Funding for Phases II and III is pending.
In this report we describe nine case studies. Drawing on existing literature, each case study includes (1) a description of the industry; (2) the current economic impact of the industry, (3) the history and reasons for the industry’s growth, as well as past and current obstacles to growth; (4) best available estimates of private and public investments in order to reach current levels of development; (5) estimates of costs and benefits of the return on investment in these regions; and similarities and contrasts to Alaska (e.g., workforce, transportation, government support programs) and relevance and applicability of the industry’s experiences to Alaska. Case studies completed include:
- Alaska salmon enhancement
- Alaska king crab enhancement
- Washington geoduck
- Florida hard cams
- Ireland Seaweed
- Spanish mussels
- Prince Edward Island mussels
- New Zealand mussels
- British Columbia First Nations aquaculture
These case studies provide insights into best practices in development of strategic mariculture initiatives, and attributes and characteristics (such as access to markets, employment base, government and public support, etc.) that have led to the success of mariculture development in other parts of the world. These factors can be compared to the current social, economic, regulatory, investment and political climate in Alaska to allow for efficient and effective development planning and implementation. The following subsections provide brief descriptions of each case study.
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The role of aquatic biomass for energyproduction •Large scale & low costs required •Micro algae are probably too valuable •Seaweed in wind farms (North Sea) could be feasible combined with extraction of alginates •Seaweed from ocean farms seems most promising for large scale biofuel production3
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Microalgae receive rising attention because of their capacity to generate biofuels. Cultured either in ponds or photobioreactors, they have a high growth rate, occupy smaller cultivation land area than other biofuel-generating land crops and use CO2 as a substrate making them promising alternative to fossil fuels.
Numerous techno-economic analyses (TEA) have assessed economic viability of the different options for microalgae cultivation, harvesting and conversion. A small meta-study of representative TEA and associated sensitivity analysis led us to identify factors that have the most influence on the outcomes of microalgae biomass use. Biological parameters such as lipid content and growth rate are commonly identified as two critical productivity parameters. Another consensus from several TEA studies is the commercial interest to produce a range of high-value co-products including animal feed and crop fertilizers that may actually compensate high costs of biodiesel production from microalgae.
In parallel, recent life cycle analysis (LCA) studies gave us some insights on the inputs and outputs of microalgae-to-biodiesel supply chain that impact on sustainability. They reveal that net energy ratio is not favorable as the production of inorganic nutrients to feed algae and bioreactor consumption in particular require a lot of energy. Greenhouse gas are also generated along the processes of biomass production and lipid extraction, making microalgae-based biofuel production less carbon-neutral than initially thought. Finally, one common favorable parameter identified as critical by TEA and LCA is wastewater, the use of which to grow microalgae can indeed reduce the costs of biodiesel production and further support sustainability.
Altogether these data indicate that the economic viability of biofuel production from microalgae remains challenging and requires the implementation of supportive policies from governments and supra-national organizations. Also, while filling the gap left by fossil fuels shortage was the initial trigger of microalgae use to produce biodiesel, their potential to contribute mitigating climate changes is today their greatest asset and warrants further R&D efforts.
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Interest in large-scale aquaculture of seaweeds in moderate temperature waters is growing. Seaweeds are a potential source of food, feed, biofuels and basis material for production of biobased chemicals. Although seaweed production is a significant market, in 2004 the world seaweed market was almost € 6 billion over 90% of which was farmed (Douglas-Westwood 2005), seaweed is not farmed at a significant scale in the North Sea.
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Marine Agronomy Group, CAFNRM, UH-Hilo
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