100 Fish as feed inputs for aquaculture – Practices, sustainability and implications
To examine the economic efficiency of the two feed types, CE and feed cost were
used. CE was calculated for each grouper farm based on the feed and production
data collected with a questionnaire and in field surveys. The standard formula for
calculating CE^5 was used.
Trash fish is widely used in the studied areas, particularly in Thailand and Viet
Nam, where availability of commercial pellet feed and its use in grouper culture are
still very limited. Farmers in Indonesia reported that stocks fed commercial pellet feed
performed poorly in comparison with stocks fed trash fish/low-value fish and that feed
costs were much higher, often becoming unaffordable.
The CE for commercial pellet feed averaged about 2.64 on the four farms in
Lampung, Indonesia, producing humpback grouper (Cromileptes altivelis) (Table
15). By contrast, the CE for trash fish/low-value fish ranged from as low as 3.1 to a
high of 18.8 across the three countries. In Indonesia, CE for trash fish averaged 7.8,
in Thailand, it averaged 12.6 for cage culture and 8.1 for pond systems, and in
Viet Nam, it was 8.2. Grouper produced using commercial pellet feed cost an average
of US$2.64/kg, while fish raised using trash fish cost from US$0.62 to US$4.80/kg to
produce, with an average production cost of US$2.20/kg for grouper produced from a
total of 21 farms. Table 15 shows the details of CE for various farms on the study sites
and the associated feed costs.
The equilibrium price level for trash fish/low-value fish at various price and CE
levels of commercial feed is presented in Table 16. At the lowest trash fish/low-value
fish price of US$0.20/kg, a CE below 13.2 provides farmers a saving on feed cost if they
use trash fish/low-value fish, while at a trash fish/low-value fish price of US$0.26/kg, a
CE lower than 10.3 permits farmers to make a significant saving on feed cost.
Based on the current study, nine of the 21 farms that used trash fish/low-value fish
had CE greater than 10.0 and three farms had CE below 6.0. It is likely that CE greater
than 10.0 is a result of overfeeding or wastage, and six farms in Thailand encountered
this problem. Survey observations indicated that farmers in Thailand tend to buy in
bulk to obtain a discount, and consequently they tend to overfeed, as they do not have
good refrigeration facilities. By contrast, farmers that have CE lower than 6.0 are likely
to be underfeeding. These farms are mostly located in Cat Ba Island, Viet Nam, where
grouper are not fed on a daily basis during winter.
Feed costs in Indonesia account for 32.2 and 40.2 percent of total production costs
for grouper (Epinephalus fuscoguttatus and C. altivelis) farmers feeding trash fish/
low-value fish and commercial pellet feed, respectively. In Thailand, feed accountsTABLE 15
Conversion efficiency (CE), feed costs and cost of production of humpback grouper in Indonesia (grouper)
and humpback and brown-marbled grouper in both Thailand and Viet Nam
Indonesia Thailand Viet Nam
Farm
No.*CE Cost (US$) Farm No. CE Cost (US$) Farm No. CE Cost (US$)
Feed Production Feed Production Feed Production
L1 2.63 2.63 11.28 K1** 15.00 3.84 10.00 CB1 4.70 0.94 5.56
L2 2.65 2.65 11.40 K2** 12.50 3.20 8.74 CB2 7.80 1.56 10.18
L3 2.65 2.65 9.43 K3** 11.40 2.93 7.99 CB3 6.70 1.34 8.80
L4 2.63 2.63 8.22 K4** 18.80 4.80 11.04 CB4 10.40 2.08 9.06
S1 7.20 1.80 8.78 K5* 7.80 2.00 5.48 CB5 16.40 3.28 11.32
S2 8.35 2.09 9.42 K6** 12.00 3.08 8.53 CB6 4.00 0.80 7.78
K7** 10.50 2.69 6.89 CB7 12.70 2.54 9.37
C1 8.10 2.07 4.40 CB8 8.10 1.62 5.68
CB9 6.00 1.20 7.37
CB10 3.10 0.62 6.73
CB11 10.00 2.00 5.38
*L1 to L4 – farms using commercial compounded pellet feeds; all others use trash fish/low-value fish
**Cage systems
Source: Sim (2006)