World Food Policy
Table 5. The Characteristics of Fish Farms in Hai Duong Province
Unit FS system
(N=51) AF system
(N=65) VAC system
(N=35)
Age
Household size Year 52.1 (9.79) 52.5 (8.35) 55.8 (8.36)
People 3.02* (1.09) 3.80* (1.12) 3.51 (1.40)
Number of laborers Labor 2.45 (0.92) 2.86 (1.10) 2.66 (1.45)
Agriculture land Sao (#) 18.7 (9.10) 18.3 (7.76) 11.7* (3.82)
Homestead land m 2 353.0* (271) 512.3* (430) 459.5 (228)
Paddy land Sao (#) 4.20* (3.48) 6.17* (3.10) 5.20 (3.42)
Area of fruit trees
Number of fruit
trees
Number of animals
raised
Area of aquaculture
land
Number of owned
ponds
Experience in aqua-
culture m 2 230 (371) 317.2 (600) 515.6 (878)
Tree 36* (56.00) 45 (64.75) 103* (171.20)
23* (26.36) 188* (234.4) 39 (36.01)
14.49 (9.58) 12.12 (7.01) 6.51* (2.46)
Ponds 2.27* (1.56) 1.88 (0.89) 1.34* (0.48)
Year 16.5 (7.23) 17.6* (7.27) 14.1* (4.85)
Heads of
animals
Sao (#)
(#)1 sao = 360 m 2 .
(*) The mean difference is significant at the 0.05 level.
Parentheses are standard deviations.
Source: survey, 2015.
health management. Often in more
intensive aquaculture production sys-
tems, there is a change in food man-
agement during a production cycle,
e.g. from an initial basis of manure and
fertilizer inputs, to a gradual shift to
pellet feeding as the main input. The
freshwater aquaculture system’s trends
are characterized by product specializa-
tion, market/commercial orientation,
off-farm or between-farm integration,
and de-integration (i.e. reduction in
emphasis on recycling flows) and great-
er emphasis on inorganic fertilizers and
fish feeds, compared with a previous re-
liance on manure or sewage as the main
nutrient sources. However, a trend to-
ward diversification of the produced
fish into the production of high-value
marketable species is emerging in the
survey sites.
In Hai Duong, polyculture is
applicable mainly for fish production
in which the number of species of fish
ranges from 2 to 6; carp being the most
common species found in stock in the
survey households. Fish were normal-
ly harvested after 10 months of being
stocked. The stocking density was cal-
culated based on the total area for fish
production (included bankers/dikes
of the pond), so the calculation of the
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