Extensive Aquaculture

1. Presented by: Hina Amir Extensive Aquaculture Topic

2.   Introduction Characteristics Food Management Productivity Advantages Disadvantages Comparison References Contents

3. Introduction Aquaculture Marine and freshwater species Categories: Extensive aquaculture. Semi-Intensive aquaculture. Intensive aquaculture.

4. C ulture and rearing in which human intervention is concentrated on the reproduction of the stock , in addition to capture. S elective increase of the production man’s food (salmon, oysters, etc.) industry ( algoculture ) pleasure (sport fishing, pearl culture, etc.). Extensive aquaculture

5. 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

6. Characteristics of Extensive Aqua culture

7. FOOD SUPPLY 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.).

8. 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.

9. Undeveloped parts of the World ( Southeast Asia ) Areas of coastal mangrove swamps, marshes, estuaries. ( not in use for other purposes ) Indonesia = six million acres Suitable Region

10. 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 Stocking and production

11. ADVANTAGES OF EXTENSIVE AQUACULTURE

12. Can be undertaken in existing farm dams. Negates the need for costly built structures. Low overheads and production costs due to no feeding and aeration requirements.

13. 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

14. 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. Disadvantages

15. 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

16. 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

17. 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) Diseases

18. Extensive aquaculture Intensive aquaculture Complete diet High density Limited space High water exchange Utilize natural productivity Low density No supplemental feeds Low water exchange

19. More Predation control More labor Large productivity qualified as ‘processing No or less predation control Less labor Small productivity qualified as ‘production’

20. 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.

21. 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