It has been well established that aquaculture will supply an increasing share of the world’s seaf... more It has been well established that aquaculture will supply an increasing share of the world’s seafood demand in the future. Most finfish are raised in marine fish cages consisting of a floating superstructure, polymer net chamber and a sinker weight(s). These systems are susceptible to large deformations, which can lead to reduction of the cage’s volume and severely impact the health of the fish stock. Net chamber deformation could be mitigated with the use of stiffer netting, such as copper alloy mesh. However, little is known regarding the bending characteristics of copper alloy nets and their relationship to the volumetric deformation of a fish cage. In this study, numerical modeling tools and techniques are developed and used to predict the dynamic structural behavior of gravity fish cages with copper alloy. An analytical model is validated by experimental testing to obtain an equivalent flexural rigidity. The model is used for finite element studies of the effect of bending resi...
Open ocean aquaculture is a rapidly growing industry with the potential to satisfy the global sea... more Open ocean aquaculture is a rapidly growing industry with the potential to satisfy the global seafood demand in the environment of declining wild fish harvesting. However, technologies developed for inshore aquaculture are not easily transferrable to the exposed fish farm locations. In particular, the structural integrity of fish cage/mooring systems, and the high cost of the maintenance (cleaning of the biofouled netting) are two major concerns in the engineering for open ocean aquaculture. This paper deals with introduction of copper alloy nets in open ocean aquaculture as a new technology to reduce biofouling, improve cage volume stability, its structural strength, and to provide additional protection from predators. Copper alloys have natural resistance to corrosion and biofouling combined with high strength and stiffness. However, these materials have higher density, different hydrodynamic properties and structural characteristics when compared to traditionally used nylon nets....
The University of New Hampshire (UNH) developed and maintained an offshore aquaculture test site ... more The University of New Hampshire (UNH) developed and maintained an offshore aquaculture test site in the Western Gulf of Maine, south of the Isles of Shoals in approximately 50 m of water. This site was designed to have a permanent moored grid to which prototype fish cages or surface buoys could be attached for testing new designs and the viability
A numerical model of an American Soybean Association (ASA) cage system was constructed using a fi... more A numerical model of an American Soybean Association (ASA) cage system was constructed using a finite element program developed at the University of New Hampshire (UNH) called Aqua-FE. The small volume, high density aquaculture system was modeled to determine how the system will operate in normal and extreme environmental conditions. The goals of the study were to determine the maximum
Netting is a basic functional and structural component of fishing nets, offshore aquaculture net ... more Netting is a basic functional and structural component of fishing nets, offshore aquaculture net pens and various fish enclosures. Advancements in the engineering analysis of nets are needed to improve design, performance and reliability of such structures. Research into the ...
... Igor I. Tsukrov1; Mustafa Ozbay1; M. Robinson Swift1; Barbaros Celikkol1; David W. Fredriksso... more ... Igor I. Tsukrov1; Mustafa Ozbay1; M. Robinson Swift1; Barbaros Celikkol1; David W. Fredriksson2; Kenneth Baldwin2: 1: Mechanical Engineering Department University of New Hampshire, Durham, NH; 2 ... Both surface and submerged positions of the net pen are considered. ...
Journal of Offshore Mechanics and Arctic Engineering, 2003
The Heave Response of a Central Spar Fish Cage. [Journal of Offshore Mechanics and Arctic Enginee... more The Heave Response of a Central Spar Fish Cage. [Journal of Offshore Mechanics and Arctic Engineering 125, 242 (2003)]. David W. Fredriksson, James D. Irish, M. Robinson Swift, Barbaros Celikkol. Abstract. As the aquaculture ...
A modified gravity-type cage, developed by SADCO Shelf Ltd., was examined using numerical and phy... more A modified gravity-type cage, developed by SADCO Shelf Ltd., was examined using numerical and physical models to determine if the cage and mooring system is suitable for an exposed site south of the Isles of Shoals, NH. The 3000-m3 SADCO Shelf Submersible Fish Cage has angled stays between the upper framework and the ballasted bottom rim (in addition to net)
This paper deals with the finite-element analysis of compliant structures containing nonlinear el... more This paper deals with the finite-element analysis of compliant structures containing nonlinear elastic components and subjected to loading by waves and currents. An efficient procedure to model such components is developed and implemented in a computer program. It can be applied to analyze nonlinear elastic ropes, rubber tethers, risers, and hoses. The elastic modulus is assumed to depend on the amount of strain in a component. The Newton-Raphson iteration scheme is modified to account for the change of elastic properties on each step of time integration procedure. The approach is applied to develop feed buoy mooring systems for the University of New Hampshire Open Ocean Aquaculture site. The complex nonlinear and viscoelastic load-elongation behavior of suitable high stretch mooring elements for this application is modeled to obtain realistic numerical predictions at sea conditions. Various designs and environmental loading scenarios are considered. Numerical simulations provide predictions of the overall dynamics of the system and maximum values of tensions in critical components.
As wild fish stocks decline, marine aquaculture is expected to play an increasing role in satisfy... more As wild fish stocks decline, marine aquaculture is expected to play an increasing role in satisfying the global need for seafood. Since the expansion of near-shore aquaculture is becoming more difficult because of multi-use issues and environmental impact concerns, the feasibility of moving aquaculture into the open ocean is being studied. To enable the optimum design and evaluation of fish
There is an increasing pressure on marine fisheries and resources, mainly by uncontrolled or over... more There is an increasing pressure on marine fisheries and resources, mainly by uncontrolled or overfishing practices. Due to the increasing need for seafood, a valuable protein source for human consumption, aquaculture has become one of the most important industries for the supply of marine fish production for future generations. The sustainability of aquaculture plays an important role in fulfilling this new duty with success. Aquaculture, the production of aquatic animals or plants for food, will have to face some challanges in the future in terms of the ecological, social and health impacts on the environment. Hence, aquaculture industry will need to diverse the production scale in to a combination of aquaculture of fed organisms (fish or shrimp) with the culture of organisms which extract either particulate organic matter (shellfish) or dissolved inorganic nutrients (seaweeds). This type of combination, the so called Integrated multi-trophic aquaculture, helps balancing the biolog...
It has been well established that aquaculture will supply an increasing share of the world’s seaf... more It has been well established that aquaculture will supply an increasing share of the world’s seafood demand in the future. Most finfish are raised in marine fish cages consisting of a floating superstructure, polymer net chamber and a sinker weight(s). These systems are susceptible to large deformations, which can lead to reduction of the cage’s volume and severely impact the health of the fish stock. Net chamber deformation could be mitigated with the use of stiffer netting, such as copper alloy mesh. However, little is known regarding the bending characteristics of copper alloy nets and their relationship to the volumetric deformation of a fish cage. In this study, numerical modeling tools and techniques are developed and used to predict the dynamic structural behavior of gravity fish cages with copper alloy. An analytical model is validated by experimental testing to obtain an equivalent flexural rigidity. The model is used for finite element studies of the effect of bending resi...
Open ocean aquaculture is a rapidly growing industry with the potential to satisfy the global sea... more Open ocean aquaculture is a rapidly growing industry with the potential to satisfy the global seafood demand in the environment of declining wild fish harvesting. However, technologies developed for inshore aquaculture are not easily transferrable to the exposed fish farm locations. In particular, the structural integrity of fish cage/mooring systems, and the high cost of the maintenance (cleaning of the biofouled netting) are two major concerns in the engineering for open ocean aquaculture. This paper deals with introduction of copper alloy nets in open ocean aquaculture as a new technology to reduce biofouling, improve cage volume stability, its structural strength, and to provide additional protection from predators. Copper alloys have natural resistance to corrosion and biofouling combined with high strength and stiffness. However, these materials have higher density, different hydrodynamic properties and structural characteristics when compared to traditionally used nylon nets....
The University of New Hampshire (UNH) developed and maintained an offshore aquaculture test site ... more The University of New Hampshire (UNH) developed and maintained an offshore aquaculture test site in the Western Gulf of Maine, south of the Isles of Shoals in approximately 50 m of water. This site was designed to have a permanent moored grid to which prototype fish cages or surface buoys could be attached for testing new designs and the viability
A numerical model of an American Soybean Association (ASA) cage system was constructed using a fi... more A numerical model of an American Soybean Association (ASA) cage system was constructed using a finite element program developed at the University of New Hampshire (UNH) called Aqua-FE. The small volume, high density aquaculture system was modeled to determine how the system will operate in normal and extreme environmental conditions. The goals of the study were to determine the maximum
Netting is a basic functional and structural component of fishing nets, offshore aquaculture net ... more Netting is a basic functional and structural component of fishing nets, offshore aquaculture net pens and various fish enclosures. Advancements in the engineering analysis of nets are needed to improve design, performance and reliability of such structures. Research into the ...
... Igor I. Tsukrov1; Mustafa Ozbay1; M. Robinson Swift1; Barbaros Celikkol1; David W. Fredriksso... more ... Igor I. Tsukrov1; Mustafa Ozbay1; M. Robinson Swift1; Barbaros Celikkol1; David W. Fredriksson2; Kenneth Baldwin2: 1: Mechanical Engineering Department University of New Hampshire, Durham, NH; 2 ... Both surface and submerged positions of the net pen are considered. ...
Journal of Offshore Mechanics and Arctic Engineering, 2003
The Heave Response of a Central Spar Fish Cage. [Journal of Offshore Mechanics and Arctic Enginee... more The Heave Response of a Central Spar Fish Cage. [Journal of Offshore Mechanics and Arctic Engineering 125, 242 (2003)]. David W. Fredriksson, James D. Irish, M. Robinson Swift, Barbaros Celikkol. Abstract. As the aquaculture ...
A modified gravity-type cage, developed by SADCO Shelf Ltd., was examined using numerical and phy... more A modified gravity-type cage, developed by SADCO Shelf Ltd., was examined using numerical and physical models to determine if the cage and mooring system is suitable for an exposed site south of the Isles of Shoals, NH. The 3000-m3 SADCO Shelf Submersible Fish Cage has angled stays between the upper framework and the ballasted bottom rim (in addition to net)
This paper deals with the finite-element analysis of compliant structures containing nonlinear el... more This paper deals with the finite-element analysis of compliant structures containing nonlinear elastic components and subjected to loading by waves and currents. An efficient procedure to model such components is developed and implemented in a computer program. It can be applied to analyze nonlinear elastic ropes, rubber tethers, risers, and hoses. The elastic modulus is assumed to depend on the amount of strain in a component. The Newton-Raphson iteration scheme is modified to account for the change of elastic properties on each step of time integration procedure. The approach is applied to develop feed buoy mooring systems for the University of New Hampshire Open Ocean Aquaculture site. The complex nonlinear and viscoelastic load-elongation behavior of suitable high stretch mooring elements for this application is modeled to obtain realistic numerical predictions at sea conditions. Various designs and environmental loading scenarios are considered. Numerical simulations provide predictions of the overall dynamics of the system and maximum values of tensions in critical components.
As wild fish stocks decline, marine aquaculture is expected to play an increasing role in satisfy... more As wild fish stocks decline, marine aquaculture is expected to play an increasing role in satisfying the global need for seafood. Since the expansion of near-shore aquaculture is becoming more difficult because of multi-use issues and environmental impact concerns, the feasibility of moving aquaculture into the open ocean is being studied. To enable the optimum design and evaluation of fish
There is an increasing pressure on marine fisheries and resources, mainly by uncontrolled or over... more There is an increasing pressure on marine fisheries and resources, mainly by uncontrolled or overfishing practices. Due to the increasing need for seafood, a valuable protein source for human consumption, aquaculture has become one of the most important industries for the supply of marine fish production for future generations. The sustainability of aquaculture plays an important role in fulfilling this new duty with success. Aquaculture, the production of aquatic animals or plants for food, will have to face some challanges in the future in terms of the ecological, social and health impacts on the environment. Hence, aquaculture industry will need to diverse the production scale in to a combination of aquaculture of fed organisms (fish or shrimp) with the culture of organisms which extract either particulate organic matter (shellfish) or dissolved inorganic nutrients (seaweeds). This type of combination, the so called Integrated multi-trophic aquaculture, helps balancing the biolog...
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