What is Cage Culture

What is Cage Culture?

Cage culture of fish utilizes existing water resources but encloses the fish in a cage or basket which allows water to pass freely between the fish and the pond. The first true cages for producing fish were seemingly developed in Southeast Asia around the end of the last century. These early cages were constructed of wood or bamboo, and the fish were fed trash fish and food scraps. Modern cage culture began in the 1950s with the advent of synthetic materials for cage construction.Today cage culture is receiving more attention by both researchers and commercial producers.
Fish cages are placed in lakes, bayous, ponds, rivers, or oceans to contain and protect fish until they can be harvested. The method is also called "off-shore cultivation" when the cages are placed in the sea. They can be constructed of a wide variety of components. Fish are stocked in cages, artificially fed, and harvested when they reach market size. A few advantages of fish farming with cages are that different types of waters can be used  such as rivers, lakes, filled quarries, etc, many types of fish can be raised, and fish farming can co-exist with sport fishing and other water uses.Cage farming in open sea is gaining popularity day by day. 
The cage aquaculture sector has grown very rapidly during the past 20 years and is presently undergoing rapid changes in response to pressures from globalization and growing demand for aquatic products. Fish consumption in developing countries will increase by 57 percent from 62.7 million metric tons in 1997 to 98.6 million in 2020.By comparison, fish consumption in developed countries will increase by only about 4 percent, from 28.1 million metric tons in 1997 to 29.2 million in 2020. Rapid population growth, increasing affluence and urbanization in developing countries are leading to major changes in supply and demand for animal protein from both livestock and fish.

The move within aquaculture toward the development and use of intensive cage farming systems was driven by a combination of factors, including the increasing competition faced by the sector for available resources, the need for economies of scale and the drive for increased productivity per unit area. Particularly the need for suitable sites resulted in the sector accessing and expanding into new untapped open water culture areas such as lakes, reservoirs, rivers and coastal brackish and marine offshore waters.

Cage culture operations

Cage culture operation involves:

Stocking: The stocking density of fish depends on the carrying capacity of the cages and feeding habits of the cultured species. For those species which are low in the food chain, stocking will also depend on the primary and secondary productivity of the sites. The optimal stocking density varies with species and size of fish and ensures optimum yield and low disease prevalence.

Feeding: Many biological, climatic, environmental and economic factors affect feeding of fish in the cages.Growth rate is affected by feeding intensity and feeding time. Each species varies in maximum food intake, feeding frequency, digestibility and conversion efficiency. These in turn affect the net yield, survival rates, size of fish and overall production form the cage. Trash fish is the main feed for yellowtail, grouper, bream, snapper and other carnivorous fish species cultured in marine cages. The shortage of trash fish is a major problem in many countries with large scale cage farming.

Farm management: Farm management must optimize production at minimum cost. Efficient management depends heavily on the competence and efficiency of the farm operator with regard to feeding, stocking, minimizing loss due to diseases and predators, monitoring environmental parameters and maintaining efficiency in technical facilities. Maintenance works are also very vital
in cage culture.

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