• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.35 no.2
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• pp.201-208
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• 1999

To develop a new fish cage which is required for offshore or moving cage culturing system has been gradually increased against being closely dense of fish cage in shallow water. Though submersible fish cage culturing system is essential technology for converting from shallow water into the offshore, it was pointed out the serious problem about stability of which are sinking and floating state. This study is presented conceptual design of submersible fish cage centered with a mooring steel pile to acquire stability and faculty. Design of mooring steel pile for submersible fish cage culturing system needs to carry out optimal design of mooring steel pile for which much efforts are required. Formulation and optimal design process of submersible fish cage are organized into using Sequential Quadratic Programming method of numerical optimization. For submersible fish cage system centered with a mooring steel pile, process of the optimal design is proposed and the optimal solutions are obtained.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.5
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• pp.690-699
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• 2011

A numerical model analysis was performed to analyze the stability of the mooring lines of an automatic submersible fish cage system in waves and currents. The fish cage system consisted of a 12-angled rigid frame, net cage, cover net, 12 upper floats, 12 tanks(for fixed and variable ballast), mooring lines, anchors, and a control station. Simulations were performed with the cage at the surface of the water and at a depth of 20 m. A Morison equation type model was used for simulations of the system in two configurations. The force parameters described both regular and random waves, with and without currents, and their values were input to the model. Mooring tension calculations were conducted on the mooring lines, grid lines and lower bridle lines of the cage. The stability of the mooring lines was checked under both static and dynamic conditions.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.46 no.1
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• pp.20-31
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• 2010

In this research, the submersible fish cage was designed to avoid structural and biological damage during harsh sea conditions. The submersible cage system consists of netting, mooring ropes, a floating collar, floats, sinkers and anchors. Whole elements of the cage were modeled on the mass-spring model. The computer simulations were carried out to investigate the dynamic behavior of the cage and to calculate mooring line tension subjected to tidal currents and waves. As expected, the tension values in the mooring line of the submerged position are 36% less compared to that of the surface cage under the same loading conditions. As the wave was used in combination with the current velocity of 1m/s, the average tensile load for the submerged cage showed 85% of the value for the floating cage. The simulation results provide an improved understanding of the behaviors of the structure and valuable information on the optimized design of the cage system exposed to open ocean environmental factors.

• Journal of Environmental Science International
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• v.22 no.6
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• pp.773-777
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• 2013

This study examined the effects of cage rearing system and backyard raising system on fatty acid profile of egg in laying hens during 9 weeks. Two hundred hens, 70-wk-old, Hy-line Brown, were used in this study and fed basal diets. 100 hens, randomly collected from facility, were transferred to cage rearing system and 100 remaining hens were moved to backyard raising system. For overall period, higher unsaturated fatty acid percentages in two different rearing systems than did saturated fatty acid (SFA) were observed. In unsaturated fatty acid compositions, both rearing system showed a higher mono unsaturated fatty acid (MUFA) contents than poly unsaturated fatty acid (PUFA) contents. Egg quality traits of laying hens reared in backyard system had considerably lower contents of SFA and higher contents of MUFA compared with eggs from cage rearing system (P<0.05). In addition, eggs from cage rearing system resulted in a significantly lower n-3 contents and higher n-6:n-3 ratios and CLA contents in comparison with backyard raising system (P<0.05). However, no significant effects of two different rearing systems on PUFA, PUFA:SFA ratio, and n-6 contents were observed during the experimental period. In conclusion, this result suggests that cage rearing system and backyard raising system will play an important role in improving egg production as functional foods.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.1
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• pp.153-161
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• 2008

Recently, the research and development of the fish cage in open sea from domestic is active and it is almost complement with commercial scale test on 'seogwipo'. But domestic technology is not sufficient of management RMS(Remote Monitoring System) with advanced country, so it is difficult to maintenance and monitor fish cage in open sea. This paper introduces a fish cage environmental monitoring system for measuring pH, DO and temperature. A signal is treated with DAU(Data Acquisition Unit) by a wireless communication method and transfers data to host computer for data processing. These data are graphically shown on the monitor with LabVIEW program and logged on the data processing system in the form of file.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.43 no.1
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• pp.38-48
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• 2007

Numerical modeling was used to evaluate the submerging characteristics of the submersible fish cage system operated by compressed air. The submerging characteristics calculated by numerical analysis as the cage was moved up and down were nearly identical to existing experiment results. Thus, the numerical model proposed in this study could be very useful in analyzing various parameters required for optimizing the design of a submersible fish cage system operated by compressed air.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.6
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• pp.989-996
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• 2008

Recently, a few types of fish-cage in open sea are researched. This fish-cage has to operate monitoring system for keeping an optimum living condition for fish. The most efficient monitoring system is WVMS(Wireless Vision Monitoring System) for fish-cage in open sea. WVMS should be able to transmit video signal and communicate with each controller. So. it needs to be based on WLAN(Wireless LAN) which has characteristic of higher transfer-rate, In this paper, we propose a structure of WVMS using WLAN equipments for maritime environment and prove its effectiveness. We present the propagation loss model of WVMS's communication channel. measured by field test, and discuss its validity compared with the predictive value based on the Friss propagation model and Plane earth reflection model. We present the number of frames that is received from WLAN modem connecting with underwater-camera in field test spots. As a result, we confirmed that proposed WVMS is suitable for maritime environment and it is possible to be applied to fish-cage in open sea on 'seogwipo'.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.56 no.2
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• pp.83-93
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• 2020

In fisheries, the importance of designing efficient fish cages is being emphasized as aquaculture has become more production than capture fishing. Particularly, the gravity cage system is one of the popular fish cage system in Korea. Currently, gravity cages of various shapes and sizes are being widely designed and installed in offshore and inland seas. The cage is subject to external forces, such as currents and waves, and the shape of the structure and tension on the ropes changes according to these external forces. Thus, it is important to accurately calculate these dynamic behavior, including the external forces and tension on the structure during the design stage. In this study, three types of cage systems with an equal internal volume of 8000 ㎥ were analyzed using mass-spring models and their behavior was interpreted through simulations. These simulations were used to analyze the behavior and tension of the ropes in response to currents and waves to aid in the selection of individual cage sizes for a given total volume. The numerical calculation results indicate that depending on the flow rate, the most resistant system is System 1, which has eight strays, and System 2 and System 3 have 69.4% and 54.8% of the resistance of System 1. Further, total resistance increased as the number of cages increased for all flow rates.

• Wind and Structures
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• v.36 no.1
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• pp.31-40
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• 2023

This paper investigates the mechanical behavior of full-scale offshore fish cages under hydrodynamic loads. To simulate different cases, different materials were used in the fish cage and analyzed under different flow velocities. The cage system is studied in two parts: net cage and floating collar. Analyses were performed with the ANSYS Workbench program, which allows the Finite Element Method (FEM) and Computational Fluid Dynamics (CFD) method to be used together. Firstly, the fish cage was designed, and adjusted for FSI: Fluid (Fluent) analysis. Secondly, mesh structures were created, and hydrodynamic loads acting on the cage elements were calculated. Finally, the hydrodynamic loads were transferred to the mechanical model and applied as a pressure on the geometry. In this study, the equivalent (von Mises) stress, equivalent strain, and total deformation values of cage elements under hydrodynamic loads were investigated. The data obtained from the analyses were presented as figures and tables. As a result, it has been shown that it is appropriate to use all the materials examined for the net cage and the floating collar.

• Journal of Environmental Science International
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• v.21 no.6
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• pp.763-768
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• 2012

The objective of this study was undertaken to investigate changes in fatty acid profile of breast and thigh muscle of old laying hens as transferred from cage to backyard raising system and to provide basic information on using old laying hens to producers for environmental managements. Overall, percentages of unsaturated fatty acid obtained from breast and thigh muscle with cage and backyard raising system are the most abundant, followed by saturated fatty acid. For breast muscle, there were no differences (P>0.05) between cage rearing system and backyard raising system in saturated fatty acid (SFA) and mono unsaturated fatty acid (MUFA). Poly unsaturated fatty acid (PUFA) and PUFA:SFA ratios were significantly higher in backyard raising systems in comparison with cage rearing systems (P<0.05). No differences (P>0.05) were detected between both rearing systems for MUFA, PUFA, and PUFA:SFA ratios with thigh muscles. SFA in thigh muscle was significantly (P<0.05) higher in cage rearing systems compared with backyard raising systems. In conclusion, using breast and thigh muscle meats from old laying hens as functional foods or investigating impact assessment on the improvement of farm management system may serve as a good management practice to encourage producers.