Abstract:
Caged fish farming at Riam Kanan Rivers, South Kalimantan has been done by the local
farmers since 1986. The huge profit from this business triggers exploitation of the rivers without
environmental consideration. As a consequence, it increased the fish mortality rate and the decrease of
fish farmers’ income. In order to control the number of fish cages, a study in regard of its condition
and/or carrying capacity is needed. The objective of this study was to estimate the amount of
phosphorus (P) waste produced by the fish farming activity. The research was conducted from six cages
with the size of 2.5 x 1.75 x 1 m3
: three cages with capacity of 220 fish per cage and the rest of 3 cages
with capacity of 500 fish per cage. Cultivated fish is common carp (Cyprinus carpio L.) with the size of 5-
7 cm long. Two times feeding per day with 5% body weight was applied. The cultivation was done for 16
weeks. The daily distribution of P of the caged fish farming was calculated based on the total amount of
leftover food and the feces in 12 hours. The weight of leftover food and the feces, collected from the net
surrounding the cages, were sampled every two weeks. The result indicated that the total P increased
with the length cultivation. The total amount of P in every cage with capacity of 220 and 500 fish were
approximately 0.035 g day-1
and 0.207 g day-1
, respectively. Hence, the optimum number of cages on
Riam Kanan Rivers based on the existing P was as follow, cages with 220 and 500 fish were 60-64 and
10-12 units per 100 m, respectively.
Description:
The level of P total resulted from caged fish cultivation was varied based
on organic waste amount produced. Although there was a tendency of increasing amount
of P total as the fish grew.
To support the sustainability of caged fish cultivation in Sungai Alang, the number
of cage units must be limited. The size of the cage suggested is 2.5 m x 1.75 m x 1 m.
There should be only around 60 units of cages every 100 m with stocking density of 50
fish m-2
. The allocation of space for cages across the river is 4 cage units which there
AACL Bioflux, 2017, Volume 10, Issue 5.
http://www.bioflux.com.ro/aacl 1096
should be 1 meter gap every 2 units. The number of cages in longitudinal position is 15
units which there should be 8 meter gap every 3 units of cages.
