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2552
2
Abstract
At present, monoculture of Sarai Phom Nang
(Gracilaria fisheri
) was not popular due to low price. Co-culture of
the seaweed and seabass (
Lates calcarifer
Bloch) in the earthen pond was one alternative way to earn more.
Abandoned shrimp ponds could be use to increase their productions. The experiment was conducted in two
earthen ponds of 30 x 45 m
2
at Division of Faculty of Science and Technology, Prince of Songkla University,
Pattani Province. The seaweed was broadcasted with initial weight of 50 g/m
2
. The fish with initial size of 10.3 ±
0.1 (mean ± SD, N=30) cm long and 13.2 ± 0.1 g weigh were used in density of 750 individuals/ pond. Every 2
weeks, biomass of the seaweed was sampling randomly by quadrat 50x50 cm
2
to weight whereas biomass of the
fish was netted and randomly took to weigh and lengthen. The results showed that maximum density of the
seaweed was found at 6
th
week of 1,015.7 g/m
2
. The relative growth rate (RGR) within 6 weeks was 3.7% day
-1
.
The density was then decreasing dramatically. The seabass showed 30.6 ± 0.6 cm in length and 429.2 ± 39.9 in
weight at 20
th
week and showed an average daily growth (ADG) of 2.97% day
-1
. Water quality parameters,
salinity, pH, water temperature, dissolved oxygen, transparency, hardness, alkaline, phosphate, nitrate, and depth
of water were 13.6 ± 7.7 ppt, 7.9±0.6, 28.9 ± 2.0
0
C., 7.9 ± 2.9 mg/l, 32.8 ± 18.1 cm., 2034.5 ± 1476.3 mg/l
137.2± 34.2 mg/l,. 0.11 ± 0.09 mg/l, 0.07± 0.19 mg/l, and 85.0± 11.0 cm respectively. Total income of the seabass
selling (25 weeks) was 46,530 bath while the income of the seaweed was zero. The low seaweed production was
obtained because of sediment, and high depth. An operation of paddle wheel aerators caused the seaweed
accumulation at the central of the pond. These might caused light obscuration
and
disease for the seaweed
decreasing after week 8
th
. However seabass show good growth and high survival rate.
Keywords :
Gracilaria fisheri
; Sarai Phom Nang, agarophyte ;
Lates calcarifer
, co-culture
