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37 Cards in this Set
- Front
- Back
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What is Aquaculture |
The farming of aquatic animals (fish, molluscs, crustaceans and aquatic plants) |
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Culture Intensity |
Intensity reflects the number of organisms per unit |
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Extensive Systems |
- Mostly self containing ecosystems that require little effort from the farmer, - the driving force is the sun for photosynthesis Example: Farm Dam (yabbies or trout) ocean ranching, long line mussel production |
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Intensive Systems |
- High maintenance and high cost culture methods - Man made environments - Lack lower trophic levels, feed is supplied by farmer - higher stocking densitys - waste treatment is usually needed - costly therefore usually only high value products Example: Sea cages, tanks, raceways |
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Integrated Aquaculture |
Or poly-culture involves the production of more than one species within the same system Example: Tilapia with rice paddies both benefit from the partnership |
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Water Quality |
The provision of water quality and quantity is a main consideration in both site selection and aquaculture production management |
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Dissolved Oxygen |
Amounts of dissolved oxygen varies geographically and seasonally, Photosynthesis can have an impact. There are often higher DO levels at the surface. - Temperature: Higher temp. lower oxygen - Salinity: Higher salinity lower oxygen - Altitude: Higher altitude lower oxygen |
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Super Saturation |
A body of water which contains more than the natural amount of a particular gas |
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Homeostasis |
Equilibrium with the surrounding environment |
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Osmosis |
Movement of water molecules from an area of high concentration to a region of low concentration through a semi-permeable membrane. |
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Freshwater Fish |
The fishes body fluids have a high ion content in relation to the surrounding environment - Result: Fish will gain water by osmosis and will lose salts by diffusion |
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Marine Fish |
These fish have a very low ion content compared to the surrounding environment -Result: Fish will lose water by osmosis and gain salts by diffusion |
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Ponds |
- %90 of global production - Natural, impoundment, excavated, levee - Topography influences the type of pond that can be used - Advantages: Can be cost effective particularly if gravity fed and drained. minimises loss of stock - Disadvantages: moderate to high land requirements and construction, no control over temp. evaporation can be high |
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Tanks and Raceways |
- Indoors or oudoors - Eliminate issues with soil and the environment - Many shapes and sizes - Raceways are long and rectangular, the have high water turnover - Fibreglass, Plastic, concrete etc. - Advantages: Easy to observe and manage stock, controlled environment, Easy to feed, high yields for a small space - Disadvantages: Original cost of build and production cost are high, increased stress, complex technology therefore risk greater risk of issues, treatment of water |
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Cages |
-Floating structures fitted with a suspended net, open culture usually in protected environment, float, collar, nets, mooring - Advantages: Requires less investment, easy installation, Inspection of fish and controlled feeding is easier, Treatment of disease is easier than pond culture. - Disadvantages: Fish feed can be wasted through the cages, Dissolved oxygen concentration can vary depending on the season with no way of controlling concentration, |
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Pens |
Are the original cage with stakes or poles driven into the ground with netting around, open culture |
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Longlines and Rafts |
long lines: horizontal headlines anchored at both ends with vertical ends cultured Rafts: vertical culture lines tied directly to the raft |
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Racks and Baskets |
Traditional oyster farming method |
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Aquifer |
A volume of geographical material i.i rock saturated with water that has filtered down from the ground surface |
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Springs |
Spring water maintains a narrow temp. range and is a clean source of water. low in oxygen |
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Fjords |
Freshwater run off from surrounding mountains can be very high in winter and during spring snow melt can cause a rapid decrease in temperatures |
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Estuary |
A semi enclosed coastal water body where salt from the open sea mixes with freshwater draining from land |
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Species Selection |
Growth Rate, Feeding requirements and habits, Reproductive biology, hardiness, marketing, economics Requirements for: Temp, DO, salinity, pH, ammonia, nitrite, nitrate |
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Site Selection |
Socio-economic considerations, Topography, water supply and quantity, Type and density of vegetation, Protection from wind etc. |
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Economics |
Profits = Total revenue - total cost Total revenue = volume of output x price/unit of output |
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Variable Cost |
- Water fees - Farm prep and maintenance - Purchase of fry, fingerlings - Fertilizers - Electricity and fuel - Labor |
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Fixed Cost |
- Depreciation of assets - Salaries - Interest - Travelling expenses - Insurance - Running Cost |
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Possible risk to loss to stock |
- Pollution - Disease - Food Poisoning - Failure of water supply - Natural disaster - Predation - Culture system failure i.e net breaking - Negligence |
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Exclude pathogen |
- Bio-security - Quarantine - Depopulate - Water treatment - Break parasites life cycle |
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Exclude Host |
- Less susceptible species - Species eradication |
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Improve Host: |
- Specific pathogen resistant - Selective breeding - immunity enhancement |
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Improve Environment |
- Good water quality - Good nutrition - Lack of predators |
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Acute Stress |
An event which the animal experiences for a short period. the stress response is quickly reversed to homestasis within hours Example: Trasportation |
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Chronic Stress |
A constant stress which the fish has now way of avoiding. Prolonged physical response that has an adverse effect on health etc. Example: Tank culture |
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Hatchery Requirements |
- Facilities for holding or rearing of brood stock - Spawning or stripping and fertilization of eggs - Incubation of eggs - Rearing of larvae to required stage |
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Egg Production |
- Stripping - Fertilization and water hardening - Incubation - Little Disturbance: low light etc Brood stock are often selected based on traits such as high growth rates, disease resistances, low maturation rates |
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Modifying Spawning Time |
Hormonal Induction: Environmental Manipulation: Can be used to alter the timing of reproduction development. |
