A Submerged Cage Designed for Aquatic Research (original) (raw)
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Aquaculture with floating and submersible cage
Gianluigi Negroni
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Engineering consideration for cage aquaculture
IOSR Journal of Engineering, 2014
Cage aquaculture has grown very rapidly during the past 20 years and is presently undergoing rapid changes in response to pressure from globalization and growing global demand for aquatic products. A cage represents a delineated volume in the body of water where the aquatic organism can be farmed. Designing and engineering are major components for cage aquaculture and it is essential to select ideal construction material, proper designing, suitable mooring and good management practices in bringing out commercial cage aquaculture which is quite simple and economically feasible. A range of cage systems is now potentially available for off-shore mariculture in world, though not all of these may prove to be effective in the intended environmental conditions and production regimes. The cost of installation and operation is also very critical. This paper provides an overview of the engineering components, and gives a brief description about various engineering materials.
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Cage culture is an utilisation of existing water bodies with little or no economic costs. The selection of a suitable site for a cage farm is indispensible for their effective function, particularly in relation to proper water quality within the cage and reduced environmental impacts around the cage and for the economic viability of the cage farm. The natural tolerance of species should be studied for assessment of suitable site.
Aquaculture operations in floating HDPE cages A field handbook
FAO Fisheries and Aquaculture Technical Paper No. 593, 2015
Global aquaculture production has been steadily growing in recent decades, increasingly contributing fish and other edible aquatic organisms of commercial importance entering national, regional and international markets. The growing demand for such products has stimulated the development and expansion of aquaculture production systems both on land and in all waterbodies, covering technologies ranging from the production of seed material to ongrowing structures and other farming support facilities. In recent decades, the aquaculture industry has also intensified its production output per unit area of space or volume, mainly to compensate, among other things, for the growing competition for land and water surfaces for other uses. The expansion of fish farming in the sea, also referred to as “mariculture”, has happened as a result of several supporting factors. These include the acquisition of reproduction and ongrowing technologies for species of interest, and the development of physical structures to contain the cultured organisms. Modern marine cages, whether floating or submersible, represent one such development. These have evolved significantly from basic and rudimental systems to sophisticated and carefully engineered structures. Many cage designs and models have been developed and are commercially available. Among these, high-density polyethylene (HDPE) cages are widely used, because of the versatility of the materials used, the relative simplicity in the performance of the various farming operations, and the comparatively limited investment capital required. Technological improvements of HDPE cages are evolving with the availability of new materials and the various equipment items needed to service all farming operations. This manual focuses on technical aspects of HDPE cages; however, the introductory chapter covers the importance of proper site selection in terms of site exposure and environmental parameters that affect the well-being of the culture fish and affect farm structures. Proper siting of a cage farm is of paramount importance with regard to the overall technical and economic success of the commercial operation, and for reducing as far as possible the environmental footprint of the farm. Prior to describing the characteristics of HDPE cages and elements making up a culture unit, the handbook describes the grid and mooring systems that support the fish cages. Information is provided on the components of the two systems, their technical specifications in relation to farm size as well as on-land assembling and sea installation procedures. A chapter focuses on the floating collar of the cage, describing the components that make up this key farming structure. The technical specifications and design options are provided for the key elements of the collar readily enabling the construction of structures that meet the needs of the operator and are suitable for the environment in which they will be placed. Technical information is then provided on the ropes, netting and net cage design and on determining the appropriate size and shape. Based on procedures developed over years of field experience, practical information on collar and net installation, net changing, maintenance and inspections technique is provided. The final sections of this publication covers practical procedures related to the stocking of cages with seed material, feeding and managing the fish stock, as well as practical information on pre-harvesting and harvesting methods, fish handling and transportation. Some information is also provided on farm safety procedures, highlighting the potential risks when working on a cage farm either on the floating structures or underwater.
Cage aquaculture : regional reviews and global overview
2007
This document contains nine papers on cage aquaculture including a global overview, one country review for China, and seven regional reviews for Asia (excluding China), northern Europe, the Mediterranean, sub-Saharan Africa, Latin America and the Caribbean, North America and Oceania, all of which were presented during the FAO Special Session on Cage Aquaculture - Regional Reviews and Global Overview at the Asian Fisheries Society Second International Symposium on Cage Aquaculture in Asia (CAA2), held in Hangzhou, China, from 3 to 8 July 2006.Each review, by geographic region, gives information about the history and origin of cage aquaculture; provides detailed information on the current situation; outlines the major regional issues and challenges; and highlights specific technical, environmental, socio-economic and marketing issues that cage aquaculture faces and/or needs to address in the future. The review recognizes the tremendous importance of cage aquaculture today and its key ...
Netting specifications and maintenance of cages for finfish culture
2009
A cage is a space enclosed with some type of mesh forming a container for aquatic animals to grow. It is typically box-shaped or tube like structure with a rope system which supports the netting material, gives shape and allows for tying to the raft unit. In box type cages, the cage is constructed of four panels at the sides and one bottom panel. Anti-predator nets are deployed around the cage to prevent entrance of predators such as sharks and sea lions into the cages. An additional net would be provided on top of the cage to prevent bird predation.
Environmental monitoring in Sea cage culture
2012
Cage culture is a fast growing industry all over the world and demands good environmental practices to assure sustainability. The sustained development of coastal aquaculture has reached a good understanding with the environment, respecting it and undertaking actions that tend to diminish the possible impacts that may arise from this activity. In order to do so, measures are to be taken in production to avoid degrading the environment, whilst still being appropriate, economically viable and socially acceptable. In this sense, it has been considered necessary to develop some basic environmental strategies to assure the best site for the aquaculture purposes, avoiding possible confrontations with other coastal uses.
Technological Approaches to Longline- and Cage-Based Aquaculture in Open Ocean Environments
Aquaculture Perspective of Multi-Use Sites in the Open Ocean, 2017
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Submersible sea-cages represent an alternative method to standard surface-based cages, and could help solve several production problems that exist in surface-based farming, such as heavy storms, algal and jellyfish blooms and attacks by predators. In this study, we investigated growth, haematological, biochemical and immunological parameters of European sea bass (Dicentrarchus labrax) farmed in surface and submersible cages, to compare the physiological status under different rearing conditions. In addition, we evaluated the use of erythrocyte HSP70 levels as a biomarker of fish welfare. The study was conducted in two submerged and two surface cages filled with D. labrax. No significant differences were observed in the growth rate and the relative condition factor between the two groups. Significantly higher levels of serum cortisol, haematocrit plasma glucose and total plasma proteins were measured in surface-based cages. Conversely, fish in submerged cages showed higher haemolytic activity and lysozyme levels in both mucus and kidney than surface reared sea bass. Results obtained in this study indicate that submergence could be a favorable condition for sea bass farming, suggesting mariculture in submerged net cages as a promising system that allows producers to minimize stress (included that from predation by fish-eating birds) and therefore favor animal welfare.