Figure 4 - uploaded by Yunil Chu
Content may be subject to copyright.
Source publication
Fish farm operators worldwide are planning to move offshore due to lack of available nearshore production sites in heavily utilized coastal zones, where there is increasing community opposition to coastal development and conflict with other usages such as shipping, fishing, tourism, conservation and recreation. Moreover, offshore sites provide more...
Context in source publication
Context 1
... and servicing vessels to survive and operate in severe sea conditions from time to time. The issue of distance from the coast or from a safe harbour or shore base is often but not always a factor." Another definition of offshore, according to the Spanish law, is the sea area outside the straight line joining two major capes or promontories (see Fig. 4). The sea space within these capes is correspondingly defined as inshore (Cabello, 2000). Holmer (2009) defined 3 classes for fish farming sites: Class 1 -coastal farming, Class 2 off-coast farming and Class 3 -offshore farming based on physical and hydrodynamical settings as shown in Table 1. It can be seen from Table 1 that distance ...
Citations
... FCs are systems that allow controlled cultivation of fish and are used in both reservoirs (Varol, 2019) and marine aquaculture (Read & Fernandes, 2003). These FCs are typically mounted on a floating platform, which may be a large buoy or a floating ring structure, and are often covered with nets or similar materials to facilitate water flow (Chu et al., 2020). Different fish species can be cultivated in FCs, and the efficiency and sustainability of these cages depend on careful feeding management and environmental impact mitigation (Qi et al., 2019). ...
Fish cages are crucial for the establishment of sustainable fish farms. The selection of fish cages is an essential subject to be examined for ensuring sustainability. This research introduces an advanced decision support model for the selection of fish cage types used in fish farming in reservoirs (R-FFs). The decision support model is based on multi-criteria decision-making (MCDM) approach and utilizes type-2 neutrosophic numbers (T2NNs). The importance levels of criteria are determined using the T2NN-Entropy method, and the ranking of fish cage types is achieved through the alternative ranking order method accounting for two-step normalization (AROMAN). The developed model is referred to as the T2NN-Entropy-AROMAN hybrid method and relies on expert opinions. Two advanced aggregation operators based on Yager t-norm and t-conorm operations, named T2NN Yager weighted arithmetic mean and T2NN Yager weighted geometric mean, are developed for aggregating T2NNs. The validity of these two aggregation operators is demonstrated. A real-life case study is developed to confirm the applicability of the T2NN-Entropy-AROMAN hybrid method. This case study focuses on the selection of fish cage types for the Artvin-Borçka R-FF in Artvin province, Turkey. The research results indicate that floating cages are the best alternative type for sustainable fish farming. Sensitivity analysis scenarios confirm the robustness of the research model and findings. The research findings, coupled with the developed model, offer valuable insights and guidance to decision-makers, researchers, and practitioners within the sector.
... Sea cages are production units for intensive aquaculture of marine finfish, located either inshore or in open waters (off-coast and offshore). Marine coastal aquaculture contribution for global aquaculture increased last decade, related with the high productivity and cost-effective operations compared to on-land facilities (Chu et al., 2020) and the capacity to contribute with largescale production to comply with the increasing consumers seafood demand. Sea cages are normally divided into fixed, floating, submersible, and submerged, and selection is based on factors such as, site conditions, environmental features, culture fish species, among other factors. ...
... Sea cages are normally divided into fixed, floating, submersible, and submerged, and selection is based on factors such as, site conditions, environmental features, culture fish species, among other factors. Environmental issues, conflict with other activities like tourism are forcing sea cage farming to move offshore to mitigate conflicts with other sea space users (Chu et al., 2020, Moro et al., 2021. Although some environmental advantages (deeper water depth and the constant water flow) and high-quality product are envisioned by moving towards the open ocean (>3 km), it represents high economical costs (Chu et al., 2020) and insufficient data exist on fish welfare. ...
... Environmental issues, conflict with other activities like tourism are forcing sea cage farming to move offshore to mitigate conflicts with other sea space users (Chu et al., 2020, Moro et al., 2021. Although some environmental advantages (deeper water depth and the constant water flow) and high-quality product are envisioned by moving towards the open ocean (>3 km), it represents high economical costs (Chu et al., 2020) and insufficient data exist on fish welfare. The sea cage structures commonly used in BoBIC region are floating flexible surface-based structures with high-density polyethylene collars, holding large nets (double net panels for protection against storms and predators, mitigating fish escapees), are normally located in bays or coastal areas. ...
The Workshop on Bay of Biscay and Iberian Coast Aquaculture Overview (WKBoBICAO) was established to assemble and synthesize aquaculture related data and information and to inform the aquaculture overview for this ecoregion
... With the breakthrough of key technologies in deep-sea aquaculture, marine aquaculture is gradually advancing into deeper waters, and aquaculture equipment is being upgraded from traditional cage systems to large-scale aquaculture platforms [5,6]. Zhao et al. [7] conducted a series of physical experiments to study the hydrodynamic response of semi-submersible aquaculture farms to waves. ...
As nearshore aquaculture spaces become saturated, the development of fisheries aquaculture for deep sea has become an inevitable trend. This paper proposes an innovative deep-sea aquaculture platform that incorporates a vessel-shaped main structure and a single-point mooring system. The potential flow theory and the Morison equation are utilized to calculate the hydrodynamic loads on the main structure and the netting and mooring systems, respectively. The deformation and force of the netting in current are simulated, and the accuracy of the analytical methods used is validated based on experimental results. The influences of the netting system on the hydrodynamic characteristics of the platform are analyzed. Optimization on the single-point mooring system is conducted under static and dynamic conditions, considering the influences of various mooring parameters, including mooring line length, buoyancy of buoys, and mass of sinkers. The patterns of changes in motion response, mooring line tension, and minimum touchdown length under different mooring parameters are calculated and analyzed. The results indicate that changes in mooring line length have minimal impact on the dynamic response of the platform and mooring system. The addition of appropriate buoys or sinkers can reduce the motion response of the platform and the tension in the mooring lines. Moreover, compared to adding buoys, incorporating sinkers more effectively enhances the overall safety and stability of the platform system.
... As shown in Fig. 1, as a typically closed floating aquaculture tank, the floating closed containment system (FCCS) as mentioned is mainly classified as the single-tank aquacultural system and muti-tank aquacultural system according to the difference in unit connection, in which the mutitank type represents the farming system is divided into several aquacultural tanks (Chu et al., 2020;Tao et al., 2023). Relative to open and semi-enclosed aquaculture systems, the FCCS exhibits numerous advantages in farming fish, for example, it can protect farmed fish against sea lice and other parasites, and the economic damage caused by predators, the algae blooms and other pollution incidents from the external environment can be completely eliminated. ...
... The optimization of the FCCS model is still in the exploratory stage, indicating it is a challenge to find prototype parameters for our model design. Fortunately, Chu et al. (2020) and Wang et al. (2020) proposed that FCCS exhibits low requirements on aquaculture devices, even a floating container can be used as an aquaculture tank. Yang et al. (2021) experimentally found that a floating breakwater with built-in ballast water tanks can efficiently improve hydrodynamic performance, including motion response and wave attenuation performance. ...
... As a result, it has become evident that exploring offshore sites for fish farming is an essential choice to maintain sustainable and high-quality fish production. In offshore fish farms, aquaculture structures, including fish cages as well as mooring lines, play a pivotal role in providing a controlled environment for fish rearing in open water meeting the rising global demand for seafood [4]. ...
... where ωp = 2π/Tp is the angular spectral peak frequency, and σ = 0.07 when ω ≤ ωp and 0.09 when ω > ωp. The value of γ is determined according to Equation (4). The wave spectrum corresponding to E1-E3 is shown in Figure 10. ...
The growth of the aquaculture industry has led to the development of innovative fish farming technologies, such as semisubmersible fish farms which offer significant advantages in terms of scalability and environmental sustainability. The study utilizes a new workflow based on an open-source finite element solver, Code_Aster, to calculate the hydrodynamic dynamic response of a fish farm. The mooring line configuration of a semisubmersible fish farm plays a crucial role in ensuring its stability and overall performance. This study presents a comprehensive numerical investigation aimed at evaluating the influence of different mooring line configurations (i.e., 4 × 1, 4 × 2, and 4 × 3) on the global performance of a semisubmersible fish farm under regular waves and irregular waves conditions. Increasing the number of mooring lines can reduce the mean and extreme tension in individual mooring lines and suppress the horizontal motions, but bring neglectable effects on the rotational responses. The findings from this research provide valuable insights into the optimal mooring line configuration for the global performance of semisubmersible fish farms.
... KJA is a fairly productive aquaculture technology which consists of net cages mounted on floating rafts in coastal waters [9]. Cultivation with marine cage technology has many advantages [10]. One of the advantages of fish farming with KJA is that fish can be kept in high density, save land, have high productivity, do not require special water management, the quantity and quality of water is always adequate, predators are easy to control, and easy to harvest products. ...
This research aimed to develop science teaching materials based on marine aquaculture bioecology using floating net cage technology that is practical and effective in improving students’ scientific literacy skills at Lombok coastal schools. This was development research based on the Thiagarajan 4D model, which consists of four stages: design, define, develop, and disseminate. The research subjects consisted of six junior high schools on the coast of Lombok, who were selected using the purposive sampling technique. The instrument used was a scientific literacy assessment of 16 reasoned multiple choice questions. Data were analyzed using normalized gain analysis. The results showed that science teaching materials based on marine aquaculture bioecology with floating net cage technology were effective in increasing the scientific literacy skills of students in the six sampled schools, obtaining an average N-gain value of 0.5 in the medium category. Keywords: marine aquaculture, bioecology, scientific literacy skills
... In contrast to traditional farming, tank culture fish farming [2] provides an opportunity to grow a large number of fish in a limited space. Figure 1 shows a Biofloc water tank. ...
Biofloc technology assists in increasing the sustainability of fish farming by reusing and recycling waste water. However, its sophisticated operation makes it very sensitive to environmental conditions. A slight disturbance in one or more parameters can lead to high fish mortality and loss. IoT systems provide an efficient way of closely monitoring the biofloc to avoid catastrophe. The best aqua conditions vary depending on the fish. Therefore, there is a strong need to explore ideal conditions for different fishes. In this work, we have focused on Tilapi fish in the southern Punjab region to find the most suitable parameters. We have developed an IoT solution for monitoring Biofloc and gathering data. We have used low-cost sensors in our product to make it feasible for poor fish farmers. Multiple machine learning algorithms such as decision trees, random forest, support vector machine, logistic regression, Gaussian naive Bayes, XGBoost and ensemble learning are applied to the collected dataset to effectively predict mortality. Our analysis exhibits that the random forest and XGBoost achieved 98% accuracy in estimating mortality. The union of IoT, machine learning, and affordability positions our study at the forefront of advancing sustainable aquaculture practices in southern Punjab, Pakistan.
... Aquaculture cages (AC), pivotal in marine aquaculture, are classified into nearshore and offshore cages, based on water depth [3]. Nearshore cages, situated in shallower waters, predominantly use high-density polyethylene (HDPE) gravity cages, valued for their simplicity and durability. ...
Floating wind turbines (FWT) are facing the challenges of high cost of energy. Integrating floating wind with offshore aquaculture cages presents a mutually beneficial approach to address cost concerns and maximize overall benefits. This study introduces and numerically models an integrated system, encompassing a self-designed semi-submersible FWT coupled and an aquaculture cage (FWT + AC). Comprehensive, fully coupled aero-hydro-servo-elastic-mooring models for this integrated system are established. Subsequently, the numerical model of the FWT is validated against wave basin model tests. The research further discusses the coupled dynamic response characteristics of the integrated system for both the FWT with and without the aquaculture cage. The results highlight that integrating aquaculture cages leads to an increase in the mean surge response by up to 12.6%, while significantly reducing pitch motion by as much as 7.69% under combined wind, wave, and current conditions. Moreover, the mean mooring loads, particularly for line 4 which faces the direction of wind, wave, and current, do not exhibit an increase of more than 15%. This integration not only enhances the stability of wind power generation under different wind degree, but also minimally impacts the average power generation efficiency, showing a variation of only about 2% under rated wind speed. The findings provide beneficial theoretical support for the design of the integrated FWT + AC system, demonstrating the potential of such integrated systems in promoting offshore sustainable development and enhancing wind energy utilization efficiency.
... Further, the research has been expanded to offshore farming and multipurpose projects such as fish cages integrated with wave energy converters and breakwaters [9], [13]- [16]. To study the dynamic behavior of the offshore cages, experimental studies are conducted on scaled models [17]- [20] and numerical studies are carried out for prototype models [16], [21], [22]. ...
The aquaculture industry is emerging exponentially because the demand for seafood is at its peak and the capture of fish production is reached its saturation point. Aquaculture is classified into nearshore and offshore farming. The nearshore cages are mostly flexible and subjected to calm to moderate sea conditions. Whereas offshore cages are robust and designed to withstand severe sea environmental conditions. The present article describes the hydrodynamic behavior of a semisubmersible square fish cage subjected to regular waves. The square cage is submerged by three different submergences of 50%, 75% and 100% overall depth with a constant water depth. A numerical analysis is carried out to study the hydrodynamic properties such as added mass, radiation potential damping, wave excitation force, motion responses and mooring line tension. The numerical work results are plotted and correlated with each case of different submergence. The cable tensions and responses of the cages are increasing with a decrease in the percentage of submersion. Among all the cases, the cage with full submergence showed better performance for all wave environmental conditions.
... Further, research has been extended to multipurpose projects like cages combined with waves, wind energy converters, and breakwaters [18]- [21]. Researchers carried out a detailed review of offshore farming [22]- [24]. ...
Cage farming has historical roots spanning centuries, while its commercialization has only commenced within the past few decades. The unsustainability of captured fish production leads to the development of the aquaculture industry. The initial practice has been carried out in ponds, rivers and later moved on into sheltered zones of the sea as a part of nearshore farming. Nowadays, farmers are keen to relocate offshore due to space constraints and pollution-related issues. This article presents a hydrodynamic analysis of the semisubmersible square fish cage with a net solidity of 0.26 subjected to regular waves. The cage is studied numerically under different drafts of 17.5cm, 26.25cm and 35cm under regular waves with a water depth of 55cm. Frequency and time domain analyses are performed to investigate the hydrodynamic characteristics of the cage. Each case's motion responses and anchor line tension are studied and results are analysed. The results indicate that the increase in draft depths leads to decreased motion responses and anchor line tensions. The cage behaves well in three different submerged conditions and shows better performance at the draft of 35cm.
