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This chapter summarizes the development of a decision support system (DSS) for spatial planning of marine finfish aquaculture sites in Southeast Asia. The DSS implements methods for site selection and estimation of carrying capacities. These methods are based primarily on results of dynamic models supplemented with in situ measurements and remote sensing information. They follow the FAO's Ecosystem Approach to Aquaculture for ensuring the proper planning and operation of aquaculture sites. In this study, the effectiveness of the DSS is demonstrated for a target aquaculture site in the northwest of Bali in Indonesia. Results of the study led to recommendations for relocation of farms to suitable areas and for reduction of fish production in farms operating above carrying capacity. Recommendations to increase fish production while ensuring sustainable ecological operation in the site were made. The DSS has broad applicability and will help to make decisions for aquaculture sites around the world. Abstrak Makalah ini menjelaskan tentang pengembangan sistem pendukung keputusan (decision support system/DSS) tentang penentuan tata ruang dalam budidaya laut di Asia Tenggara. Penerapan metoda DSS untuk pemilihan lokasi dan penentuan daya dukung perairan utamanya berdasarkan model dinamis yang dilengkapi dengan pengukuran mutu perairan in-situ dan informasi penginderaan jauh. Metode ini termasuk prosedur umum dalam kontek pendekatan ekosystem akuacultur oleh FAO untuk memastikan perencanaan yang tepat dan operasional yang benar di lokasi budidaya laut. Dalam studi ini efektivitas DSS didemontrasikan di lokasi budidaya laut yang terletak di perairan Utara-Barat Bali-Indonesia. Hasil dari penilaian lokasi ternyata keramba jaring apung (KJA) pembudidaya diletakkan diluar area perairan yang sesuai untuk budidaya laut dan produksi ikannya berlebih. Rekomendasi untuk penempatan KJA yang sesuai untuk meningkatkan produksi berkelanjutan telah dilakukan. Dengan demikian dapat disimpulkan bahwa DSS mempunyai penerapan yang sangat luas dan dapat membantu dalam penentuan lokasi budidaya di seluruh dunia.

The Eastern Mediterranean Sea is known as oil pollution hotspot because of high marine traffic and a growing number of oil and gas industrial activities inside, which makes efficient monitoring oil spills important in this area. Spaceborne Synthetic Aperture Radar (SAR) plays an important role for oil spill detection with its advantage of wide coverage and all-weather observations. However, discriminating whether the dark formations in the SAR imagery are from actual oil spills or look-alikes has been a challenging part. This study applied You Only Look Once version 4 (YOLOv4) object detection algorithm as an one-class (i.e. oil spill) object detector for learning oil spill features inside the Region of Interests (ROIs) and the background information from the rest of the image. The preliminary results pointed out that the pixel threshold for removing some tiny oil spills is suggested as they appeared regularly in the study area but are hardly visible. The average precisions (AP) of the trained model on validation and test sets are 67.80% and 65.37%, showing that the model is not overfitting on our training and validation sets. In addition, this study recommended some data augmentation strategies which might help improve the results.

In this paper, results of a tidal stream resource assessment performed for the Strait of Larantuka, Indonesia are presented. The methodology followed is comprising of the estimates of power yield and evaluation of the effects of power extraction via high-resolution, three-dimensional flow models. Power densities exceeding 10kW/m2 are observed in the main channel. Current velocities, and wake characteristics of the turbines have been resolved reasonably well with low computational cost, considering different levels of energy dissipation. Although the results are promising, investigations using in-situ measurements alongside more advanced modelling techniques are still needed, and currently underway.

The Strait of Larantuka, with highly energetic tidal stream currents reaching speeds of up to 3&ndash, 4 m/s, is a promising site for renewable electricity production from the ocean. This paper presents the results of an assessment regarding the potential hydrodynamic impacts, wake characteristics, and the performances of large scale turbine arrays in the strait. A high-resolution, three-dimensional baroclinic model is developed using the FLOW module of the Delft3D modeling system to simulate tidal currents. The energy of currents is assumed to be extracted by horizontal-axis tidal turbines, which can harness strong bi-directional flow, positioned on sequential rows and alternating downstream arrangements. Enhanced momentum sinks are used to represent the influence of energy extraction by the tidal turbines. Four different array layouts with rated capacities of up to 35 MW are considered. We find that, in the Strait of Larantuka, array layout significantly affects the flow conditions and the power output, mainly due to the geometric blockage effect of the bounded channel. With respect to undisturbed flow conditions in the strait, decreases in current speeds of up to about 0.6 m/s, alongside increases in the order of 80% near-shore are observed. While operating efficiency rates of turbines reaching around 50%&ndash, 60% resulted during the spring tide in the arrays with smaller rated capacities, the power output of the devices was negligible during the neap tide.

This paper presents the development of a simple and generally applicable hydrodynamic method for the estimation of production carrying capacity (PCC) of coastal finfish cage aquaculture. Dimensional analysis was used to find significant and general interdependencies between the hydrodynamics at fish farm locations and particulate wastes deposited on the seafloor by fish farms. Modeled ratios of deposition to emission of particulate wastes underneath fish farms were found to be primarily a function of the flow Reynolds numbers at the farming locations and the non-dimensional settling velocity of emitted wastes. In the non-dimensional model, farming conditions include daily feed rate, proportion of unconsumed feed, and carbon content in feed and fish feces. The relationship can be used to estimate the PCC of floating net cages imposing a threshold value for deposition. Results of in-situ assessments of the benthic impacts of several fish farms in an aquaculture site in the northwest of Bali, Indonesia were used to validate and demonstrate the effectiveness of the method. Predicted results were able to clearly identify fish farms operating beyond ecologically sustainable carrying capacity. The proposed method has broad applicability and could help make decisions regarding the estimation of production potential of individual farms in pristine areas, for providing first estimates in sites that have scarce data, and for assessment, expansion, and optimization of the currently operating aquaculture sites in Southeast Asia, China and potentially other data-poor island nations. As the method relies on dynamic models, it enables straightforward assessments over the entire aquaculture region.

A multi-criteria assessment methodology that accounts for physical and environmental constraints is applied to assess the tidal stream power potential at eleven straits between Indian Ocean and inner Indonesian seas. In this paper, preliminary results of an assessment at the Strait of Larantuka are presented. The tidal stream power potential is evaluated on the basis of a calibrated and validated numerical model. It was found that the average tidal stream power density at some of the locations can exceed about 6kw/m2 and the practically exploitable energy yield from the Strait of Larantuka is about 20Gwh per year.

All North Sea countries are confronted by climate change impacts such as accelerated sea-level rise, increasing storm intensities resulting in as well higher set-up of storm surges as growing wave energy and a follow-up of morphological changes. Thus it is necessary to question the effectiveness of existing coastal protection strategies and to examine alternative strategies for coastal protection under a range of scenarios considered possible. Scenarios of accelerating sea-level rise leading to changes in sea level of up to 1 m or more by 2100 and higher set-up of storm surges with increasing wave energy have been used for planning purposes. Adaptation strategies for future coastal protection have been established in all North Sea countries with vulnerable coasts, observing two propositions: (1) structures are economic to construct in the short term and their dimensions easily adapted in the future to ensure flexibility in responding to the as yet undeterminable climate change impacts and (2) implementation of soft measures being temporarily effective and preventing counteraction to natural trends. The coastal protection strategies differ widely from country to country, not only in respect of distinct geographical boundary conditions but also in terms of the length of the planning period and the amount of regulations. Their further development is indispensable and emphasis must more and more be laid on strategies considering the effects of long-term development of coastal processes for future coastal protection. Filling gaps in knowledge is essential for developing sustainable adaptation strategies.

Mariculture (marine aquaculture) has been intensified and has created essential employment opportunities over the last two-decades in Indonesia, as well as many other countries in the world. This development has also augmented environmental concerns and questions about possible environmental impacts. Considerable amounts of nutrient waste in dissolved and particulate form were released by intensive fish faming into the environment through feed excess, soluble fish excretion and faeces production. One of the first steps to avoid the dangerous environmental impacts is careful site selection. Hence, before the implementation of fish farming mariculture activities, appropriate site conditions for culturing the species should be selected in order to minimize environmental impacts arising from the farming activities (sustainability) as well as to guarantee adequate conditions from the operational point of view (suitability). The paper focuses on the development of a Decision Support System (DSS) as a tool for the decision maker in coastal zone management and mariculture for the appropriate selection of mariculture site location. Extensive use of GIS as part of the Decision Support System was deployed in this study. The DSS is based on physical, chemical and sediment criteria as well as on data of conflicting coastal use. The GIS analysis results in a map indicating the suitable areas for the improved method of offshore cage mariculture. In this study, emphasis was placed on finfish species, however the methods and results may be employed for other species as well following some modifications. The DSS was applied for the western part of Java Sea, Indonesia. The data were acquired from direct field measurement, numerical modelling and existing information from particular agencies. Numerical modelling was used to obtain spatial and temporal distributions of hydrodynamic parameters (i.e. current velocities and water levels). The Delft3D modelling system (Delft Hydraulics, The Netherlands) was employed for this purpose. The DSS was developed under GIS application of ESRI® ArcGIS™ using weighted overlay method. Due to lack of data, some parameters were excluded from the analysis. The results showed the adequacy of the system for supporting governmental authorities in the implementation, environmental controlling, and estimation of overall carrying capacity for environmental sustainable marine fish farming.

In this paper, an advanced methodology developed for the assessment of tidal stream resources is applied to several straits between Indian Ocean and inner Indonesian seas. Due to the high current velocities up to 3-4 m/s, the straits are particularly promising for the efficient generation of electric power. Tidal stream power potentials are evaluated on the basis of calibrated and validated high-resolution, three-dimensional numerical models. It was found that the straits under investigation have tremendous potential for the development of renewable energy production. Suitable locations for the installation of the turbines are identified in all the straits, and sites have been ranked based on the level of power density. Maximum power densities are observed in the Bali Strait, exceeding around 10kw/m2. Horizontal axis tidal turbines with a cut-in velocity of 1m/s are considered in the estimations. The highest total extractable power resulted equal to about 1,260MW in the Strait of Alas. Preliminary assessments showed that the power production at the straits under investigation is likely to exceed previous predictions reaching around 5,000MW.

The objective of this paper is to give an overview of the present status of the developments, limitations, difficulties, future trends and demands in the applications of the finite element models to real world problems. Apart from describing the three dimensional flow solvers employed and two applications to complicated real world problems, some important aspects such as pre-and post-processing, verification and validation of computer models as well as computer performance are also included.