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Fish Farming IGCSE
Transcript of Fish Farming IGCSE
What is Fish Farming?
Types of Fish Farming
Fish are high in PROTEIN, low in FAT
Fish are efficient at converting Biomass
Good for human diet
Over 1 billion people eat fish regularly
Demand is growing , putting pressure on wild fish stocks
Like farming controlling variables increases yields
Maintenance of water quality
Water quality is maintained by fresh water moving through the pond, lake or sea tank.
Maintaining flow, filtering and aeration ensures good water quality
-high oxygen levels
-low toxin levels
Water quality can be monitored
Diet of fish can be controlled
Protection against predators
Pesticides can kill parasites
Quality and yield of fish can be improved
by Mr Woolf
Fish farming is the principal form of aquaculture.
Fish farming involves raising fish commercially in tanks or enclosures.
Open system- Usually a lake or pond
Closed System- Artificial pond or tank
Farmed sea fish grown in special tanks suspened in sea water
Explain the methods which are used to farm large numbers of fish to provide a source of protein, including maintenance of water quality, control of intraspecific and interspecific predation, control of disease, removal of waste products, quality and frequency of feeding and the use of selective breeding.
Disease & Pests
Feeding frequency & quality
Maintenance of water quality 2
In closed systems waste products and left over food build up encouraging microorganism growth. These could cause disease, so the ponds need to be emptied and cleaned regularly.
Interspecific predation is prevented by:
In fresh water farms fish need to be protected from birds and mammals such as otters with netted cages over the ponds.
In sea fish farming the tanks are covered by nets to protect the fish from birds. They are protected from sea predators such as seals and dolphins by strong metal cages.
Different species of fish are kept in separate tanks
Intraspecific predation is prevented by:
Keeping the fish in smaller numbers in each tank or pond.
Keeping fish of different ages in different enclosures
Fish of different genders are kept separately (unless being bred)
Disease & Pests
The high densities in which the fish are kept mean they are more prone to pests and diseases. This is avoided by.
Keeping water sterile
The fish are treated with pesticides and antibiotics to control this.
Removing waste products regularly.
To increase the size of fish, rate at which they grow and overall yield,fish are fed:
High quality feedstock with essential nutrients maximising energy transfer
Little and often to prevent overeating and discourage competition
Growth hormones can be added
Competiton between different species
Competiton within the same species
Farmers can ensure they produce fish with the desired charcteristics.
1.Eggs and sperm from the adult fish are removed and mixed in the lab.
2.The eggs are hatched in tanks of gently flowing water.
3.When the fish have grown to a suitable size the best fish are selected (biggest and most healthy) are allowed to breed.
Potential spread of disease, as animals are closer together
Antibiotics used may not be degraded before human consumption
Can cause eutrophication from food pellets and animals' faeces
Pestcides could be toxic to non-harmful species
Fish pellets are made from 'wild' fish stocks, and may deplete numbers