Fish Farming (Edexcel IGCSE Biology)
Revision Note
Fish Farming
Benefits of fish farming
Most fish are still caught in the wild (i.e. in the open ocean or in freshwater rivers and lakes)
However, overfishing has lead to dramatic declines in many fish populations
Fish farms are ways of raising large numbers of fish in a small space to provide food (protein) for humans
This has several advantages over wild-caught fish, including:
The ability to selectively breed fish to ensure high quality, fast-growing fish
The ability to protect against predators
The ability to control water quality (many wild-caught fish have significant levels of pollutants such as mercury in their flesh)
The ability to control feeding to ensure rapid growth
Methods used in fish farms to ensure high yields
Within fish farms, large numbers of fish are kept in freshwater or seawater enclosures and are carefully monitored and controlled in many different ways
This helps to ensure high yields (fast growth of healthy fish)
The methods used include:
The control (and maintenance) of water quality
The control of intraspecific predation
The control of interspecific predation
The control of disease
The control (and removal) of waste products
The control of the quality and frequency of feeding
The use of selective breeding
Fish farming methods table
Method | Explanation |
|---|---|
Maintenance of water quality | Water is filtered to remove waste and harmful bacteria to prevent diseases. Water is also cleaned to maintain high levels of oxygen for aerobic respiration |
Control of intraspecific predation | Intraspecific predation: predation within the same species |
Control of interspecific predation | Interspecific predation: predation between different species |
Control of disease | Antibiotics are given to fish to prevent disease which might otherwise spread quickly due to their close confinement, increasing the chances of survival. They are also kept in small numbers to minimise the spread of diseases |
Removal of waste products | Water can be filtered to remove waste products such as faeces and sewage. Fences, nets and tanks are cleaned or location of fish can be changed to ensure clean water |
Quality and frequency of feeding | Fish are fed food that is high in nutrients to ensure fast growth. They are fed frequently but in small amounts so they do not overeat or start eating each other |
Use of selective breeding | Fish are separated by gender so that selective breeding can be used by farmers to only allow fish with desired characteristics to reproduce. This ensures that the stock of fish is fast growing as these genes get passed on much more frequently |
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