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Twenty years ago, offshore aquaculture – fish and shellfish farming in U.S. federal waters – was an emerging technology with tremendous potential. The United States and other countries were at the forefront of an engineering and technology revolution, much like the old race to the moon. Bit by bit, scientists, engineers, and researchers began to figure out the “how” for this type of aquaculture. They developed dependable cage systems, remote feeders, monitoring systems, and broodstock for species that would thrive in the open ocean environment. Every success fueled more interest. The potential for this type of seafood production was obvious – so were the challenges. Could this type of aquaculture be brought online safely as a way to complement wild harvest? Would it be economically viable? What about license to operate?

Today, aquaculture in federal waters is among the most talked-about technologies associated with the future of seafood production in the United States. This recent wave of interest in the offshore has strong roots in Chapter 24 of the U.S. Commission on Ocean Policy’s September 2004 report to Congress, An Ocean Blueprint for the 21st Century. In its report, the Commission recommended that the National Oceanic and Atmospheric Administration (NOAA) develop a comprehensive, environmentally sound permitting and regulatory program for marine aquaculture.

In December 2004, the Administration responded to Commission recommendations with the President’s Ocean Action Plan. That plan specifically called for national legislation to allow aquaculture in U.S. federal waters. The Administration’s legislative proposal to establish a regulatory framework was submitted to Congress in 2005 and again in 2007. The latter proposal also calls for an expanded research program for all of U.S. marine aquaculture.

The introduction of national legislation for marine aquaculture garnered attention in the media and spawned a useful and ongoing national debate about the role of domestic aquaculture in America’s seafood supply. That debate centers around a host of marine management, economic, environmental, conservation, health, social, and regulatory issues. It also includes the eventual design of aquaculture regulations for federal waters and associated federal programs. As the agency at the center of the debate, and the one that would likely be tasked with developing and implementing any new federal regulations, NOAA commissioned a study group composed of fisheries resource economists and business experts to address key economic issues associated with offshore marine aquaculture. That effort resulted in this report, Offshore Aquaculture in the United States: Economic Considerations, Implications & Opportunities.  

The potential of seaweeds as feedstock for oil-based bioproducts was investigated, and the results support seaweeds as a biomass source for oil-based bioproducts. Seaweeds have not traditionally been perceived as a suitable feedstock for oil-based bioproducts because of their low content of lipids and fatty acids. In contrast to this perception the first major outcome of this thesis was the provision of new benchmark species of seaweed for oil-based bioproducts, selected because of their high oil contents combined with high proportions of omega-3 polyunsaturated fatty acids (PUFA(n-3)), which are the target fatty acids for high value products in health and nutrition. The three key species of seaweed identified were Spatoglossum macrodontum, Dictyota bartayresii and Derbesia tenuissima with high total lipid contents (~ 12 % dry weight (dw)) and high total fatty acid contents (4 – 8 % dw). These species also had a high proportion of PUFA(n-3) which were ~ 20 % of total fatty acids (TFA) in S. macrodontum and D. bartayresii and over 30 % of TFA in D. tenuissima. The second major outcome of this thesis was then the identification and quantification of natural variability of fatty acids within the key species of seaweed which can be exploited for further improvements in the content and composition of fatty acids. For S. macrodontum, the content of TFA (55 – 83 mg g⁻¹ dw) and the proportion of PUFA(n-3) (16 – 25 % of TFA) varied substantially (~ 50 %) on a temporal scale. For D. bartayresii, the content of TFA (45 – 55 mg g⁻¹ dw) varied slightly (~ 20%) and the proportion of PUFA(n-3) (16 – 24 % of TFA) varied substantially (~ 50 %) on a temporal scale. There was also spatial variation for D. bartayresii which was ~ 50 % for the content of TFA (36 – 54 mg g⁻¹ dw) but less than 10 % for the proportion of PUFA(n-3) (18 – 20 % of TFA). The third major outcome of this thesis was then the demonstration that environmental parameters are drivers for fatty acid variability in these species. The first line of evidence was from seasonal field-based studies on S. macrodontum and D. bartayresii which showed a higher proportion of PUFA(n-3) in winter when water temperature and light availability were at their annual minimum (~ 40 – 50 % higher in winter). In a second line of experimental evidence for D. tenuissima, colder water temperature was identified as the major driver (explained ~ 40 % of the total variability) to improve the proportion of PUFA(n-3) by ~ 20 % in this species. In a similar manner, high light intensity reduced the quality of the biomass by increasing saturation. The fourth major outcome of this thesis was the identification of a relationship between biotic parameters (plant size and life cycle stage) and fatty acids. In D. bartayresii, plants with a larger thallus length had significantly higher contents of TFA and slightly higher proportions of PUFA(n-3) and in S. macrodontum older plants in their "decline phase" had a more saturated fatty acid profile than younger plants in their "growth phase". Both the environmentally and biotic driven variability in fatty acids can be exploited through culture and harvest strategies to improve the fatty acid content and quality in these feedstocks. The fifth major outcome of this thesis was for the first time the provision of evidence for the genotypic variability of fatty acids within species of seaweed which is the basis for selective breeding to improve the yield of target fatty acids. First, there was substantial spatial variability (~ 40 – 60 %) in the content of fatty acids between the sampling locations of D. bartayresii, suggesting genotypic differences between populations. The second line of evidence was from experimental data on isolates of D. tenuissima where the content of TFA ranged from 34 to 55 mg g⁻¹ dw and 49 % of the variation was genotypic (between isolates). The proportion of PUFA(n-3) ranged from 31 to 46 % of TFA with a strong interactive effect of genotype and water 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. And last, the sixth major outcome of this thesis was the identification of fatty acid variability within individual plants. The content of TFA and to a lesser degree in the composition of fatty acids varied substantially within plants of S. macrodontum (TFA: 21 – 106 mg g⁻¹ dw) and D. bartayresii (TFA: 40 – 57 mg g⁻¹ dw) with a higher content of TFA and a higher proportion of PUFA(n-3) in the upper sections compared to the base. Overall, this thesis provides the basic framework on which to develop strategies for the domestication of seaweeds for the production of oil-based bioproducts in a similar manner to the past improvements in the oil yield of terrestrial oil crops and also microalgae. The most important domestication steps identified in this thesis were species selection and permanent improvements in the content and composition of fatty acids through selective breeding with D. tenuissima being the prime target species for this process.

Boergesen (1937) reported Bostrychia tenella (VahI.) J. Ag. from Indian waters. Some details regarding the morphology of the alga are available to some extent by the works of Montagne(1828).Falkenberg (1901). Post (1936). Tseng(1942)and Joly (1954) . The detailed structure of the alga and the development of the reproductive structures are not known completely. Advantage was taken of the occurrence of Bostrychia tenella in the Gulf of Mannar at Mandapam to study the morphology of the species both from living specimans and from material fixed in 4% formalin and forma lin -acetic-alcohol. Suitable preparations were stained in eosine and mounted in glycerine for microscopic examination. Sometimes the material had to be softened by placing in 1 % acetic acid or 1 % lithium chloride solution. While thin sections were used frequantly. most datails could be observed on whole mounts and squashes of suitable pieces of the thallus of the alga.