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.

1. Presented by: Hina Amir

2. 1. Introduction
2. Characteristics
 Food
 Management
 Productivity
3. Advantages
4. Disadvantages
5. Comparison
6. References

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

4. 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.).

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

7.  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

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

12. 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.

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.

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)

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

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

21. 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.

22. • 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