Academic literature on the topic 'Integrated Multi-Trophic Aquaculture (IMTA)'

<p>Budidaya laut berbasis Integrated Multi-Trophic Aquaculture (IMTA) merupakan opsi pengembangan budidaya perikanan yang sejalan dengan konsep pelestarian lingkungan. Tujuan penelitian ini adalah menganalisis performa komoditas budidaya laut yang pada sistem integrated multi trophic aquaculture (IMTA). Penelitian dilaksanakan di Teluk Gerupuk, Lombok Tengah, Nusa Tenggara Barat, pada bulan Juni-November 2015. Model IMTA yang dikembangkan adalah kombinasi antara ikan kerapu macan (<em>Epinephelus</em> <em>fuscoguttatus</em>), ikan bawal bintang (<em>Trachinotus blochii</em>, Lacepede), dan rumput laut (<em>Kappaphycus</em> <em>alvarezii</em>). Hasil penelitian menunjukkan bahwa selama 150 hari masa pemeliharaan ikan kerapu dan bawal bintang menghasilkan pertumbuhan yang baik, dengan rata-rata bobot akhir ikan kerapu sebesar 173,45 ± 36,61 g/ekor; dan<br />ikan bawal bintang sebesar 161,27 ± 30,05 g/ekor. Pertumbuhan rumput laut selama tiga siklus menunjukkan bahwa siklus pertama (Juni-Juli) dan siklus kedua (Agustus-September) menghasilkan pertumbuhan yang lebih baik dibandingkan dengan siklus ketiga (Oktober–November). Laju pertumbuhan harian rumput laut di sekitar keramba jarring apung (KJA) ikan sebesar 4,22%-6,09%/hari lebih tinggi dibandingkan dengan kontrol (jarak 2-3 km dari KJA ikan) yaitu 3,90%-5,53%/hari. Hasil dari penelitian ini menunjukkan efektivitas sistem IMTA dalam hal peningkatan produktivitas budidaya rumput laut. Model IMTA dapat diterapkan sebagai model pengembangan budidaya laut yang berwawasan lingkungan melalui peningkatan produksi, sistem produksi bersih, dan berkelanjutan.</p><p>Mariculture activity with Integrated Multi-Trophic Aquaculture (IMTA) is an aquaculture development technique which in line with environment conservation concept. This study was aimed to analyze perfomance of mariculture commodities that cultured under integrated multi-trophic aquaculture (IMTA) system. The study was conducted in Gerupuk Bay, Central Lombok, West Nusa Tenggara during June-November 2015. The IMTA model was combined between tiger grouper fish (Epinephelus fuscoguttatus), silver pompano fish (Trachinotus blochii, Lacepede), and seaweed (Kappaphycus alvarezii). The result showed that during 150 days of cultured periods, both of grouper and pompano indicated a good growth performance, with mean body weight at the end of culture period about 173.45 ± 36.61 g/ind. and 161.27 ± 30.05 g/ind., respectively. Seaweed growth performance from three cultivation cycles showed that cycle-1 (June- July) and cycle-2 (August-September) had better growth performance than cycle-3 (October November). Daily growth rate of seaweed that cultured near fish cages was higher (4.22%-6.09%) than control, 2-3 km distance to fish cages (3.90%-5.53%). This study indicated the effectiveness of IMTA system to increase seaweed culture production. IMTA model can be applied as development model of mariculture with environmental concept through production enhancement, zero waste production, and sustainability.</p>

In this study, we investigated if juvenile European lobsters Homarus gammarus would eat waste from Atlantic salmon Salmo salar cages in a coastal integrated multi-trophic aquaculture (IMTA) setup and if there were any impacts on growth. Trophic interactions between salmon and lobsters were assessed using δ15N and δ13C stable isotope analysis and fatty acid profiling from fish feed as indicators of nutrient flow. Analysis revealed that lobsters directly utilised particulate waste from salmon production, as levels of indicator fatty acids from salmon feed were significantly higher in lobster tissues near the fish cages compared to the control site. Route of uptake may have been direct consumption of waste feed or faecal material or indirectly through fouling organisms. Stable isotope analysis did not indicate nutrient transfer to lobsters, suggesting that the duration of the study and/or the amount of waste consumed was not sufficient for stable isotope analysis. Lobsters grew significantly over the trial period at both sites, but there was no significant difference in lobster growth between the sites. Our results show a trophic relationship between salmon and lobsters within this IMTA system, with no apparent advantage or disadvantage to growth.

Ett stagnerat globalt fiske har lett till en snabb utökning av vattenbruket för att tillgodose den globala marknaden. Traditionellt vattenbruk har i västvärlden kännetecknats av monospecifika odlingar, ofta med mycket grav påverkan på sin omnejd. Ett återupptäckt alternativ till denna i längden ohållbara tappning av vattenbruk har därför växt fram. Integrerad multi-trofiskt vattenbruk (IMTA) är en teknik som, genom att odla organismer från flera trofiska nivåer tillsammans, kan minska utsläppen och öka produktiviteten hos en odling. En växande global befolkningen kommer dock leda till ökande konflikter mellan kustnära vattenbruk och intressenter såsom industrier, myndigheter och privatpersoner. Då vattenbruket fortsätter att växa skulle en lösning på dessa konflikter vara att rikta dess expansion mot det öppna havet. Frågan är då om IMTA vore effektivt utomskärs och hur det i så fall skulle kunna optimeras ur både produktions- och kostnadsperspektiv. Denna undersökning tyder på att en pelagial expansion skulle ge en positiv påverkan av de olika ekologiska, ekonomiska och infrastrukturella aspekter rörande utomskärs-IMTA. Dock kräver en sådan förflyttning omfattande förarbete i utvärdering av lämpliga lokaler. En analys av olika arter och dess egenskaper, monetära värde, tillika möjligheter att optimera systemet visar på att utomskärs IMTA är möjligt, men begränsas av ingenjörsmässiga faktorer.
The stagnated global fishing has led to a fast expansion of aquaculture to meet the increasing global demand for seafood. Traditionally aquaculture in the western world has been defined as large monospecific cultures, often with grave implications on its surrounding environment. An alternative to the conventional and unsustainable method has thus been rediscovered and developed. Integrated Multi-Trophic Aquaculture (IMTA) is a technique that, by cultivating organisms of different trophic levels together, can decrease effluents and increase the productivity of a farm. Furthermore, the growing global population will lead to increasing conflicts between coastal aquaculture and other stakeholders such as industries, governments, and private citizens. Since aquaculture continues to grow, a possible solution to such conflicts could be an offshore expansion of aquaculture. However, whether an IMTA system still would be effective in an offshore setting is unclear. This is also the case regarding the possibility to optimize an offshore IMTA system concerning productivity and investment costs.  The present article shows that a pelagic expansion of IMTA would positively affect the ecological, economical and infrastructural aspects regarding offshore IMTA compared to inshore IMTA. However, such a transposition would require comprehensive preparatory evaluations of suitable sites. An analysis of several species and their attributes, monetary value, and capability of optimizing the system indicates that offshore IMTA is possible but is limited by structural-engineering factors.

Among efforts to develop sustainable approaches towards the intensive rearing of finfish within open marine waters, is the development of integrated aquaculture techniques. Integrated Multi-Trophic Aquaculture (IMTA), has been promoted as a way to reduce unwanted environmental impacts associated with the intensive production of marine finfish within net-pens. The principle aim of this concept, is the bioremediation of nutrient discharges from fish aquaculture. This is to be achieved by integrating fish cultivation with the growing of species from lower trophic levels, which use the nutrient discharges as a food source. Many studies have been performed that investigate the ability of various species of macroalgae to remove dissolved nutrient discharges, and the ability bivalves to remove solid-bound nutrients, presented as either fish faeces, or an enhanced production of phytoplankton that may be promoted by nutrients emitted by fish-farms. IMTA has also been suggested as a means to improve overall productivity per unit of feed applied to fish, through the conversion of nutrient emissions into additional biomass, such as the tissues of macroalgae or bivalves. Within the research community which focuses upon the environmental impacts of aquaculture, there is a growing awareness that sustainable solutions to aquaculture production cannot be realised through a focus restricted to the growing-phase, and to a limited set of environmental impacts which may this activity may produce. This is because changes to a specific production phase often promote changes at phases located elsewhere along a products value chain. Life-Cycle Assessment (LCA), is a method employed for modelling the environmental impacts that may potentially be generated across the value chain of a product. It is particularly useful for identifying instances of environmental impact shifting; a term used to describe situations where efforts to reduce the contribution of a specific production phase towards one or more environmental impacts, has the effect of either displacing this contribution to another phase, or increases the contribution of production towards different environmental impacts. Despite its apparent suitability, LCA has not previously been fully applied to the environmental impact modelling of open-water IMTA systems. The work presented in the following thesis advances this research front, by using LCA to explore the potential for environmental problem shifting occurring as a consequence of replacing intensive monoculture production, with IMTA. Comprehensive datasets have been acquired from the Chilean aquaculture industry, describing the production of aquafeed and Salmo salar, as well as for the production of the Phaeophytic macroalga, Macrocystis pyrifera, and the molluscan bivalve, Mytilus chilensis. Using LCA methodology, the production of salmon feed, and the production of S.salar, M.pyrifera and M.chilensis, have been assessed for their capacity to contribute towards a variety of global-scale, environmental impacts. IMTA consisting of either S.salar and M.pyrifera, S.salar and M.chilensis, or all three of these species, and combined at ratios required for a bioremediation efficiency of 100 %, 50%, or 20 % of either nitrogen or phosphorous emission from fish, is compared to the monoculture production of S.salar. The comparison is based upon a standardised functional unit, with each species produced through IMTA, being modelled as part of the reference flow required to fulfil the functional unit. Monoculture is compared to IMTA upon the basis of nutritional function, by using a functional unit of mass-adjusted protein content, and mass-adjusted economic value. The use of economic value is based upon the ‘best-case’ assumption, that it serves as a proxy for the total nutritional function that each product offers to human society. The LCAs presented in this study have produced a number of results. Salmon ingredients derived from agricultural crops and animals account for the majority (between 71 % to 98 %) of contributions towards the impacts of compound salmon feed. In general, agricultural crops ingredients contribute more to these impacts than do agricultural animal ingredients, and account for between 31 % and 87 % of the contributions from all ingredients and inputs. In contrast, the combined supply of fish meal and fish oil from capture fisheries is responsible for between 0.13 % and 11 % of all impacts. Vegetable oil accounts for the vast majority of contributions from ingredients derived from agricultural crops. Vegetable oil is modelled as a 50 : 50 blend of sunflower oil and rapeseed, oil, but sunflower oil accounts not only for most of the contributions from vegetable oil, it is responsible for over 50 % of the contributions that all agricultural crop based ingredients contributes towards some impact categories. Replacing sunflower oil with rapeseed oil reduces the contributions of salmon feed by between 6 % and 24 % across 10 out of the 11 impact categories. When compared upon the basis of equal weight, the contributions of fish oil are between 18 % and 99 % lower than those from rapeseed oil. The production of feed is responsible for the majority of contributions (between 32 % and 86 % ) to all impacts of salmon grow-out production. The production of salmon-smolts accounts for between 3 % and 18 %. The majority (64 %) of contributions towards the eutrophication potential of salmon production are from nutrient emissions, which are the result of fish metabolism, whilst nutrients released through the production of feed, the majority of these being from the agricultural production of crop and animals, account for 32 %. Feed production is also a major contributor to the impacts of land-based smolt production, but these contributions (between 12 % and 37 % across all impact categories) are of a lower magnitude than those from the supply of feed to the grow-out phase. Inputs of salt, and inputs of both electricity produced in a diesel power generator and obtained from the national electricity network, are also notable contributors (between 5 % and 67 %, 4 % and 29 %, and 2 % 47 %, respectively) towards the impacts of smolt-production. The main contributors towards the potential impacts of kelp grow-out production (excluding eutrophication potential) are the supply of infrastructure (between 14 % and 89 %), operation of a diesel-powered motorboat for maintenance purposes (between 1 % and 89 %), and the supply ‘of seeded cartridges’ (between 9 and 49 %). The major contributors from the production of ‘seeded cartriges’ in a land-based facility are the supply of electricity from the national electricity network, the supply of fresh water, and the treatment of waste water. The impact potentials of producing seed in this facility might be reduced if the scale of operation is increased. Removal of nitrogen and phosphorous upon the harvesting of kelp is calculated based upon kelp tissue contents of these nutrients. The harvesting of 200 tonnes ha / yr-1, results in a eutrophic potential with a negative value (-376.51 kg of phosphate equivalents). The removal of such a quantity of nutrients might be beneficial if the local marine environment is at risk of hypernutrification, but when no such problem is present, the potential for undesirable consequences of nutrient sequestration should be considered. The major contributor towards the impacts of mussels is the provision of infrastructure (between 25 % and 99.5 %, excluding eutrophication potential). Infrastructure is also responsible for the majority of contributions from mussel seed production. The provision of cotton mesh bags, which are used to aid attatchment of seed to drop-ropes in the grow-out phase, account for between 37% and 99 % of the contributions from the infrastructure from the grow-out phase. This result suggest that either the impacts of mussel production can be reduced by using an alternative material with lower environmental impact potentials, or the inventory data describing the producing of cottonmesh bags requires some improvement. The outcomes of the LCAs of the different IMTA scenarios, are interesting. The results show that choice of species, and the ratios of their combination as required for the different efficiencies of bioremediation, can have a significant effect upon the comparison between IMTA and monoculture.
The study demonstrates a potential for environmental problem shifting as being a consequence of IMTA, especially when the functional unit is mass-adjusted economic value. As bioremediation efficiency increases, contributions towards eutrophication decrease. However, this reduction is achieved at the cost of increasing the contributions of IMTA towards those impact categories, such as ‘ozone layer depletion,’ for which it has a greater contribution than does monoculture. In general, it cannot be concluded from these results that open-water IMTA represents a more sustainable alternative to the monoculture production of Atlantic salmon. The sustainability of IMTA is shown to be dependent upon a variety of trade-offs, between individual environmental impacts, and between these impacts and the nutritional function that the system is capable of providing.

Mestrado em Biotecnologia - Biotecnologia Industrial e Ambiental
O consumo de macroalgas pelos seres humanos tem vindo a aumentar nos últimos anos, o que está relacionado, para além do valor nutricional que lhes é reconhecido, com os seus compostos biofuncionais benéficos para a saúde. Assim, há a necessidade de aumentar sua produção de forma sustentável, onde os sistemas de Aquacultura Multitrópica Integrado (IMTA) surgem como uma alternativa promissora à aquacultura convencional, envolvendo mais de um nível trófico. No âmbito do controlo de qualidade deste novo tipo de alimento, surge um desafio: as macroalgas são organismos que tendem a bioacumular elementos potencialmente tóxicos (PTEs). O objetivo deste estudo foi monitorar a concentração de Cd, Pb, Hg e Al na macroalga Ulva rigida cultivada na empresa ALGAplus num sistema IMTA implementado pela empresa na Ria de Aveiro e inferir de um possível impacto dos factores de produção na concentração destes elementos nas algas. Avaliaram-ase três diferentes situações que poderiam influenciar a acumulação de PTEs nas algas: densidade de cultivo, taxa de renovação da água e época do ano (sazonalidade). Foi ainda feita uma comparação entre espécies cultivadas na empresa e pertencentes a outras classes: Fucus vesiculosus e Gracilaria sp. O teor de Cd, Pb e Al na biomassa de macroalgas foi determinado por atomização com plasma associada a deteção com espectroscopia de massa (ICP-MS), após digestão com ácido e microondas. O teor de Hg foi determinado por absorção atómica após combustão da amostra em atmosfera de oxigénio. As concentrações de Pb, Cd, Hg e Al para a Ulva rigida foram 0.3-3.1, <0.05, 0.01-0.03, e 121-3178 μg/g (peso seco – DW), respetivamente. A variabilidade sazonal não foi significativa (ρ > 0.05), e as condições de cultivo apenas influenciaram estatisticamente o teor de Pb (ρ < 0.05). Todos os valores obtidos para os PTEs quantificados estão abaixo do valor limite indicado na legislação que regula a qualidade das algas para consumo humano, o que evidencia que neste sistema IMTA não ocorrem problemas de contaminação com PTEs.
Macroalgae consumption by humans has been increasing in the last years, which is related with their biofunctional compounds with health benefits. Therefore, there is the need to increase their production in a sustainable way where Integrated Multi Trophic Aquaculture (IMTA) emerges as a promising alternative to conventional aquaculture that involves more than one trophic level. Quality assurance of this new aliment is crucial and that is why this study is so important: macroalgae are known to be high bioaccumulators of potentially toxic elements. The objective of this study is to monitor the concentration of Cd, Al, Pb, and Hg in Ulva rigida during the year, assessing possible correlations with the cultive conditions and seasonality. There were evaluated three situations that could influence PTEs accumulation in macroalgae: cultivation density, water renewal rate and season. A comparison was made with other species also cultivated in the company and belonging to other classes: Fucus vesiculosus and Gracilaria sp. Cd, Hg, Pb and Al content in macroalgal biomass was determined through plasma atomization and mass spectrometry detection (ICP-MS), after acid and microwave digestion. Hg content was determined through atomic absortion after oxygen-rich combustion of the sample. Concentrations of Pb, Cd, Hg e Al in Ulva rigida ranged as it follows: 0.3-3.1, <0.05, 0.01-0.03, e 121-3178 μg/g dry weight (DW), respectively. Seasonal variability was not significant (p >0.05), and cultivation conditions were significant only for Pb (p< 0.05). All values obtained are below the limit of legislation which proves that in the IMTA system there are no relevant problems related with potential toxic elements accumulation in macroalgae

Over the last few decades, Integrated Multi-Trophic Aquaculture (IMTA) in South Africa has developed from early experimental designs to large scale, commercially operating farms. This was in response to uncertainty regarding food availability for stock (primarily kelp in the case of abalone farms) and a desire to recirculate water whilst reducing the environmental footprint of the abalone farms. The growing prevalence of IMTA as a commercially viable activity has brought about a need for an expansion of the knowledge pool regarding the physico-chemical processes at work in such systems. Of particular interest to researchers are mechanisms and dynamics of nutrient transfer between components of the system and how these could be manipulated to increase efficiency and reduce running cost of farms. This work was conducted to try and quantify some of the changes in some physical and chemical characteristics of the water stream on a large-scale IMTA farm cultivating seaweed of the genus Ulva (Ulva rigida) and the locally named perlemoen abalone (Haliotis midae) on the south west coast of South Africa (Viking Abalone Farm at Buffeljagsbaai, Western Cape, South Africa) (34.7550° S, 19.6154° E). Experiment one was a three-day experiment taking place in December of 2018, there was no particular reason for the choice of month, analyses of this nature are potentially useful on any given day of any given month as although the literature contains plenty of gaps, there is no single identifiable data gap sufficient to encourage the use of particular timeframes. The sampling regime involved single sample point testing of three modular clusters each operating a different rate of water recirculation (50%, 75% and 100%) with 50% recirculation being standard farm operation, 75% and 100% tested to gauge effect of increasing recirculation, 75% tested as a potential standard farm operation to reduce load on pumps and reduce volumes of water pumped in, 100% tested in case of emergency situation which requires farm to be isolated from the inbound water stream arriving from the immediate coastal water, ambient conditions were also tested for reference and comparison. Parameters tested were those which the farmers already tested periodically to gauge changes in water quality which may effect the abalone or seaweed, though slightly different methods were used for the testing of ammonia. On the farm the standard method is the Nesler photometric test (Lovibond photometer), whereas this research was conducted using a calibrated indophenol blue spectrophotometric technique (Modified Grasshoff, 1976). Results showed no statistically significant differences (Mood's Median Test, p>0.05) between the 50% and 75% recirculation cluster for temperature, pH, Total Ammonia Nitrogen (TAN) or Free Ammonia Nitrogen NH3 (FAN). At 100% recirculation, statistically significant differences (Mood's Median Test, p0.05) occurred for temperature. At 100% recirculation, TAN and FAN increased rapidly, though the commensurate rapid and considerable decrease in pH meant the FAN increase was not as high in magnitude as it would be at 4 a normal seawater pH of around 8.2. Abalone suffered no mortalities at 100% recirculation for three days and later reports from the farmers suggested no noticeable drop in growth rate that could be attributed to this test in the months following the experiment. From the regulatory perspective, the TAN levels breached WWF guideline maximum effluent concentrations for abalone aquaculture (600µM/l) only in the 100% recirculation cluster, and only then during three of the thirteen sampling runs. The TAN concentrations in 50% and 75% recirculation treatments were far below the WWF guideline maximum effluent concentration with maximum concentrations of 7.15 µM/l in 50% and 13.46 µM/l at 75%, the increase in maximum concentration was large but not egregious and resulted from a more pronounced build-up of ammonia as residence time of water in the cluster increases at 75% recirculation. Experiment two was an intensive 24-hour sampling run; the primary aim was to test the effectiveness of the seaweed biofilter in an Integrated Multi-Trophic Aquaculture (IMTA) farm culturing perlemoen abalone and a green macroalga. Parameters tested were temperature, pH, dissolved oxygen, salinity, TAN, nitrate and nitrite as these are relevant parameters for the farmer and the necessary equipment to test them was available. Samples were stored in a freezer for this experiment due to intensity of sampling regime, and spiked standards were prepared to check shifts in concentration of TAN, nitrate and nitrite that may have resulted from the freezing and thawing processes. Spike recoveries were good in the case of TAN (87%-98%) and nitrite (92%-96%), but random and widely dispersed in the case of nitrate. As such, nitrate and nitrite were removed from the analysis as nitrite values only really held value if taken in conjunction with nitrate values. Minimal and non-useful variation in salinity observations meant that salinity was also discounted from the analysis. Temperatures varied minimally between sampling points during the experiment, though they rose in all sampling points during daytime as would be expected. pH was higher in abalone inbound and Ulva effluent water compared to the abalone effluent water. Total ammonia nitrogen percentage removal across the seaweed biofilters ranged from 65%-85% with the mean and median at 73% and 71% respectively. Free ammonia nitrogen percentage removal across the seaweed biofilters ranged from 41%-80% with the mean and median removals at 63% and 66% respectively. A regression analysis demonstrates a strong positive linear relationship between TAN removal and TAN load to the seaweed biofilter (r2= 0.90). Principal component analysis revealed a strong negative correlation between FAN removal and pH, as pH increased across the seaweed biofilters, the level of FAN removal decreased. This suggests that the perceived benefit of increasing pH in seaweed biofilters during the day-time may have some negative repercussions.

The recent research focus on integrated multi-trophic aquaculture (IMTA) is redefining the aquaculture industry's approach to intensive aquaculture. More sustainable farm model systems that include multiple farm products with integrated trophic levels are being developed. While these systems may be economically and environmentally more sustainable, it is important to realize that integrating farm products also changes disease risk on farms. This is illustrated by examining how finfish disease risk can increase or decrease depending on the pathogen in a simple finfish / blue mussel (Mytilus edulis) IMTA system. Mussels bio-accumulate and repackage the opportunistic pathogen, Vibrio anguillarum, into infectious fecal particles increasing the potential risk of infection and creating new transmission pathways. In contrast, mussels appear to inactivate the viral pathogen, Infectious Salmon Anemia Virus (ISAV) and potentially serving a role in reducing the transmission of the virus onto and off of IMTA farms.

To understand disease risk on IMTA farms, it is no longer adequate to simply investigate how a given pathogen interacts with its host under a range of environmental conditions. Evaluating the disease risk in IMTA systems requires a better understanding of how pathogens may potentially interact with all of the components of the farm system, while recognizing new potential pathways that may be created or enhanced within and by the system its self. Through a more comprehensive understanding of these potential interactions farmers can apply a range of bio-security and best management practices to limit the risk of disease on IMTA farms. With good management IMTA farms should not increase the risk of disease, but may actually reduce the spread of pathogens in some situations.

Sea-based integrated multi-trophic aquaculture (sIMTA) was explored as an amalgam of the processes of polyculture and biofiltration, with the primary objectives of improved aquaculture production efficiency and wastes remediation. The study established a coculture of Atlantic salmon (Salmo salar, L.), Pacific oyster (Crassostrea gigas, Thunberg) and sugar kelp (Saccharina latissima, L.), in Scotland, and explored their production in relation to the background environment, historical aquaculture production modes, regulation and resource-use. The field trials demonstrated the dominance of the ambient environment in regulating trophic linkage of co-cultures. Enhanced growth of the bivalve and macroalgal components, over reference cultures, was only observable when ambient nutrients were limiting or favoured food, i.e. phytoplankton, was scarce. Localised differences within and between sealoch systems were also observed to be of importance. The complex physical processes of particulate waste dispersion and dissolved nutrient diffusion were simulated using established models and field data drivers. This process illustrated the potential benefits of designing the integrated farm to optimise trophic linkages as well as considering the final fate of wastes. The application of sIMTA was explored within the current regulatory regime, illustrating what regulatory gains (statutory and non-statutory) might be possible on account of the process and how the products of integration, as studied, are likely to meet with few regulatory food safety constraints within a UK market. The scarcity of aquaculture resources, partly through inefficient use, was explored. sIMTA is presented as a method which could possibly alleviate some of these resource-use inefficiencies when ambient environment supports, and as such sIMTA is proposed to qualify for priority resource allocations, in the context of greater socio-economic advantage.

La production de crevettes en Indonésie est en constante augmentation de part sa surface et l'intensification de ses élevages. Cette filière contribue au développement économique en milieu rural, à la sécurité alimentaire nationale, à l'emploi et au commerce extérieur. Cependant, ce développement rapide s'est accompagné d'effets écologiques et sociaux négatifs. Le développement de maladies dans les élevages ainsi que la dégradation de l'environnement côtier a conduit à l'abandon de 250 000 hectares de bassins dans le pays. Leur réhabilitation dans le cadre d'une activité durable est aujourd'hui une priorité pour le gouvernement indonésien.L'objectif de cette thèse est de développer des outils et des méthodes, basées sur de l’imagerie satellites à très haute résolution spatiale (THRS), (1) pour une meilleure gestion des sites de production et (2) pour réhabiliter les sites abandonnés. L'estuaire de la Perancak situé dans la Province de Bali, une zone de production en déclin, a été choisi comme site pilote. Ce travail a été réalisé dans le cadre du projet INDESO dont l'objectif était de fournir des outils et des méthodes pour une meilleure gestion des ressources côtières et marines en Indonésie.Le premier outil développé pour objectif de cartographier automatiquement les bassins d'élevage. A cet effet, une méthode basée sur la détection des contours a été mise en place et comparée à deux autres méthodes, la première basée sur la méthode de croissance des régions, la seconde sur une classification non supervisée (plus particulièrement la méthode Isocluster). Notre méthode a permis de détecter une forte proportion de bassins avec une meilleure précision.Le second outil avait pour objectif de distinguer les bassins actifs des bassins abandonnés. Un indicateur intégré (IPAI) basé sur quatre critères identifiés sur les images THRS que sont la présence d'eau, d'aérateur(s), de ponton(s) d'alimentation et de végétation, a été développé. Cet indicateur permet de distinguer significativement un bassin actif d'un bassin inactif. La présence de ponton est le critère qui s'est révélé être le plus discriminant.Cet indicateur a été utilisé sur l'estuaire de la Perancak pour suivre la dynamique d’abandon des bassins, liée au développement des maladies dans les élevages, entre 2001 et 2015. Deux facteurs de risque conduisant à l'abandon ont été mis en évidence : le climat et le positionnement des bassins au sein de l'estuaire. Ces résultats suggèrent qu'une approche spatiale doit être prise en compte pour la réhabilitation des bassins. Trois zones ont été définies à partir de leur résilience spatiale aux maladies. Le niveau de connectivité entre des bassins via le réseau hydrologique augmente le risque d'abandon. A noter que la présence actuelle des pathogènes (White Spot Syndrome Virus, WSSV) dans les bassins et probablement dans l'environnement génère une mémoire écologique défavorable à la réhabilitation de fermes aquacoles de crevettes.A partir de ces résultats, une première proposition de plan pour réhabiliter les bassins abandonnés a été formulée dans le cadre d'une approche écosystémique. Pour lutter contre les maladies, ce plan suggère de développer une aquaculture multi-trophique intégrée (AMTI), basée sur la diversité des espèces élevées et de leur positionnement dans la chaine trophique, à l'échelle de l'estuaire. Les méthodes et les études qui doivent être conduites pour rendre opérationnelle cette proposition sont discutées
Shrimp farming production in Indonesia has continuously increased through a large expansion of cultured areas and stocking density intensification. This activity supports rural economic development and contributes to national food security, employment and foreign exchange earnings. However, this development has generated adverse ecological and social effects. As consequences of diseases and environmental degradations, there are currently 250,000 ha of abandoned ponds. Their rehabilitation, within a sustainable aquaculture framework, is actually a high priority for the Indonesian government.The objective of the present PhD work was to develop tools and methodologies to (1) enable better management for operating sites of shrimp industry and (2) rehabilitate abandoned sites using very high-resolution satellite (VHRS) imagery. The Perancak Estuary, located in Bali Province, is the production area in decline that has been chosen as study site. This work has been carried out in the frame of the INDESO project which was assigned to develop and provide tools and methods for better management of marine and coastal resources in Indonesia.The first developed tool was an automatic classification procedure for aquaculture mapping. A method based on Edge Detection on VHRS images was proposed and compared with those generated by Region Growing segmentation and unsupervised classification Isocluster. Edge Detection method could successfully create aquaculture map in the Perancak estuary by identifying a large proportion of existing ponds, with good overall accuracy.To implement effective procedure for appropriate aquaculture ecosystem assessment and monitoring, the second tool was an Integrated Pond Activity Indicator (IPAI). It aimed to discriminate active from abandoned ponds and was developed based on four criteria using VHRS images. Those criteria were: presence of water, aerator, feeding bridge and vegetation. This indicator succeeded in detecting active pond with a good accuracy, and feeding bridge appeared to be the most discriminant criteria.This second indicator has then been applied to the Perancak estuary to highlight the abandonment dynamic due to disease between 2001 and 2015. Two risk factors that could contribute to explain dynamics of abandonment were identified: climate conditions and pond locations within the estuary, suggesting that a spatial approach should be integrated in planning processes to operationalize pond rehabilitation. Three areas were defined based on their disease resilience. Ponds connectivity through water network increased the risk of disease development. The continued presence of shrimp pathogen species in ponds and probably in the environment (i.e. White Spot Syndrome Virus, WSSV) may generate ‘ecological memories’ that prevent to the return of shrimp productive system.These results were used to establish a first proposal of rehabilitation plan using an ecological approach. At the whole ecosystem scale, the development of an integrated multi-trophic aquaculture (IMTA), based on the diversity of cultured species and their trophic status would be implemented. Methods and studies that would be conducted to operationalize sustainable pond rehabilitation are briefly discussed

Ulva as an aquaculture crop and IMTA component species has received mixed results globally; success has been achieved in South Africa and Israel, whilst in Europe the results have been poor. This project aims to determine if Ulva lactuca is a suitable candidate as an inorganic extractive species component within marine IMTA systems in British Columbia. The inorganic extractive feasibility of U. lactuca was determined with combination of real time growth and nutrient uptake experiments, alongside a SWOT analysis and literature review to reveal the possible potentialities and pitfalls. U. lactuca was cultivated in 680 litre tanks in the effluent of Wolf Eels, Anarrhichthys ocellatus in a recirculation system at the Aquatics facility at the University of Victoria. Growth experiments of wild local U. lactuca strains attained summer growth of up to 17.43% specific daily growth rate, with winter growth of up to 4.26% specific daily growth rate. U. lactuca demonstrates a preference for Ammonia-N uptake over other forms of inorganic nitrogen and a reduced nutrient uptake capacity during dark periods. Nitrate uptake capacity up to 202µm N gDW-1 day-1 was exhibited. These figures display the excellent biological potential of local Ulva lactuca strains to act as an inorganic extractive. However currently, long term maintenance of the crop proved problematic with instability with growth rates and nutrient uptake capacity. Cultivation issues in combination with poor economic outlook will restrict the feasibility of this species to specific types of IMTA system. Beneficial steps towards the deployment of U. lactuca inorganic extractive components would include: (i) the identification of suitable sterile strains or employment of “germling” spore production, (ii) the use of a rotational, light weight, cage cultivation system, (iii) being farmed in combination with a dark period nutrient removal species, such as Chondrus crispus, (iv) being farmed in conjunction with in-situ algivorous species.
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Recently the shrimp farming has blooming as a crucial counterpart in the aquaculture industry which contribute the remarkable role in sea food production as well economy of the country. However, this could be fluctuated every year through several circumstances such as unfavorable (Poor water and soil quality) environmental factors. The environmental factors includes disease causing bacterial pathogens in the soil and water which causes the bacterial diseases in the aquatic animals, like this hectic problems are prevented through bioaugmentation strategies. The pond environment plays a vital role in determining the healthy culture system, but there is high risk for manipulation by bacterial community which takes care of waste generated in the system through in situ bioremediation. Due to the impact of rapidly growing bacterial diseases of shrimps throughout the world, numerous studies have been carried out to find immunostimulants, immunomodulators and biotic component that can be used against vibrio causing pathogens, and can also be used as an alternative for antibiotics. Recent research focus towards the marine resources such as microalgae, seaweed, live feeds (like artemia, copepods, rotifers), bacteriophage, and probiotics have been found to have higher potential in reducing vibriosis. Eco-based shrimp farming includes green water technology, phage therapy bio-floc technology (BFT) and integrated multi-trophic aquaculture (IMTA), these methods hold a promising alternative to antibiotics in the near future. Bacterial diseases caused by vibrios have been reported in penaeid shrimp culture systems implicating at least 14 species and they are Vibrio harveyi, V. splendidus, V. parahaemolyticus, V. alginolyticus, V. anguillarum, V. vulnificuslogei etc.

Abstract Continually increasing demands on aquaculture products drive the current monoculture to upgrade and upscale because of not only economic but environmental sustainability reasons. Over the past decade, open water integrated multi-trophic aquaculture (IMTA) practiced as a potential alternative has been demonstratively illustrated from both scientific and public attention. Basing on previous studies of this synergistic aquaculture system, we, here, studied the physical environment in Onagawa Bay as the cornerstone for further IMTA implementation. Onagawa Bay locates in Miyagi Prefecture, Japan, and because of its mature practice on polyculture, it is recognized as a suitable site for IMTA. Unfortunately, the earthquake and tsunami in 2011 caused a huge uncertainty on physical environment changes. Still insufficient researches have been conducted on physical environment study, especially through modelling method. Here, adopting the three-dimensional Marine Environmental Committee (MEC) ocean model, we described the setup and validation for Onagawa Bay in this research. At the present stage, simulation results can best fit observation data on the tidal elevation with the correlation coefficient between observed and simulated tidal elevation reaching 0.96, captured the main characteristic of flow velocity, and exhibited homogenous tendency towards water temperature. Furthermore, through the plot of the residual velocity field and statistical seasonal velocity distribution, potential aquaculture configuration has been discussed spatio-temporally on the hypothesis that high current speeds contribute to the further implementation.