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Uploaded byhina amir
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Extensive Aquaculture

The document presents information on extensive aquaculture. It describes the characteristics of extensive aquaculture such as utilizing natural food sources with low stocking densities and production. The advantages are low costs due to no feeding requirements but disadvantages include habitat destruction and invasive species. It compares extensive and intensive aquaculture and lists references.

Presented by: Hina Amir
1. Introduction 2. Characteristics  Food  Management  Productivity 3. Advantages 4. Disadvantages 5. Comparison 6. References
• Aquaculture • Marine and freshwater species Categories:  Extensive aquaculture.  Semi-Intensive aquaculture.  Intensive aquaculture.
Culture and rearing in which human intervention is concentrated on the reproduction of the stock, in addition to capture. Selective increase of the production  man’s food (salmon, oysters, etc.)  industry (algoculture)  pleasure (sport fishing, pearl culture, etc.).
• Not rely on excessive working in the growing process. • The stock is left to grow on its own, utilizing natural food sources. • Fish chosen for extensive aquaculture are very hardy • Prawns, muscles, seaweed, carp, tilapia, tuna and salmon
 Utilizes natural photosynthetic production of food (algae, plankton, molluscs, crustaceans) to feed the fish.  (insect larvae, snails; and worms).  Certain producers provide additional feed.  Examples – Carp, in mixed farming with other species (whitefish, catfish, etc.).
Water Management Water management is totally dependent on tidal fluctuation. Water change is effected through tidal means, i.e., new water is let in only during high tide and the pond can be drained only at low tide.
• Undeveloped parts of the World (Southeast Asia) • Areas of coastal mangrove swamps, marshes, estuaries. (not in use for other purposes) • Indonesia = six million acres
• Low stocking densities (e.g., 5 000-10 000 shrimp post larvae (PL)/ha/crop) • The ponds used for extensive culture are usually (more than two ha) and may be shallow • Production is generally low at less than 1 t/ha/y
1. Can be undertaken in existing farm dams. 2. Negates the need for costly built structures. 3. Low overheads and production costs due to no feeding and aeration requirements.
4- Low labor costs.  low stocking densities  less attention to water quality issues and stock monitoring . 5- Many other uses of the waterway, such as recreational boating and fishing, occur simultaneously
1- Natural habitat destruction Example: • Philippines, shrimp aquaculture, destruction of thousands of acres of mangrove fields • Benthic habitats are being depleted, organic waste produced by the fish.
• Phytoplankton and algae, reduces the amount of available oxygen in the water column, kills the Benthic organisms. 2-Another serious problem, extensive aquaculture is the introduction of invasive species into ecosystems
3- Foreign fish interbreed with wild species, upset the genetic variability of the species, more prone to disease and infection. 4- Some farmers protect their stocks from predatorily birds such as pelicans and albatross by shooting sometimes endangered creature
5- Diseases and Parasites Example: • "black gill " disease caused by fungus, bacteria or detritus. Necrosis and browning of exoskeleton, 6- A non-reliable water supply (e.g. drought)
• Intensive aquaculture • Extensive aquaculture • Complete diet •Utilize natural productivity •High density •Low density •Limited space •No supplemental feeds •High water exchange •Low water exchange
More Predation No or less predation control control More labor Less labor Large productivity Small productivity qualified as qualified as ‘processing ‘production’
REFERENCES • Allen, .(1989). Freshwater Fishes of Australia. T.F.H Publications: New Jersey, USA. • Mackinnon, M. (1995). Fish for Farm Dams. Queensland Department of Primary Industries, Brisbane. • . • NSW Fisheries (1994). Freshwater Crayfish Advisory Pack. NSW Fisheries, Sydney.
• Tidwell, J. H. (2012) Aquaculture Production Systems ,John Wiley & Sons, ISBN0813801265 :pp.88-89 • McCormack, G. and Jackson, P. (1991). The Farm Fish Book - Proceedings of the Seminar on Stocking Fish in Farm Dams for Recreation and Farm Table Use. Queensland Department of Primary Industries, Brisbane