Pengaruh faktor-faktor persekitaran terhadap pertumbuhan dan kemandirian tiram komersil, crassostrea iredalei (faustino) di kawasan penternakan tiram di kg. Telaga Nenas, Perak.
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Date
2007-06
Authors
Loris, Izwandy
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Abstract
A study was done on the commercial oyster, Crassostrea iredalei that was
cultured at an oyster culturing site in Kg. Telaga Nenas, Perak which located at an
estuarine area. This study was done for duration of 17 months on the effects of the
environmental factors on growth of size, monthly weight wet and mortality of C. iredalei.
The environmental factors studied in this study were divided into 3 groups. They were
the physical factors (total suspended solids, turbidity, current speed, daily salinity and
temperature), chemical factors (nitrate, ammonia, phosphate and pH) and biological
factors (diversity and density of phytoplankton and concentration of chlorophyll-a). The
results showed that the overall mortality of commercial oyster, C. ireda/ei at Kg. Telaga
Nenas, Perak are low. The highest percentage of mortality recorded was 6.33 ± 1.15%
in October 2003. The percentage of survived C. iredalei at the end of the study was
62%, which was above 50% from total population and can be considered profrtable.
However, the size and wet weight of C. iredalei showed a relatively low growth
throughout the study period. Results from Pearson Correlation test showed the
mortality of C. iredalei have an intermediate correlation with ammonia (r= -0.454),
turbidity (r= -0.529), minimum daily temperature (r= -0.405), salinity (r= -0.548), and
dissolved oxygen (r= -0.456) while other environmental factors showed a low or very
low correlation (r ~ 0.390). As for the size of C. iredalei, all the environmental
parameters showed either low (0.20.::s_r.::s_0.39) or very low correlation (0.19.::s_r). However,
for the weight of C. iredalei, only pH showed a high correlation (r= -0.720). The other 7
environmental parameters (nitrate, phosphate, TSS, current speed, daily maximum and
minimum temperature and phytoplankton density) showed intermediate correlation
{0.40<r<0.69) with the weight of C. iredalei. The outcome from intensive samplings in
December 2004 and January 2005 also revealed that there were no significant
differences (P>0.05) between environmental parameters before and after the oyster's
baskets except for DO and turbidity in January 2005 where the value obtained before
and after the oyster's basket are significantly different (P<0.05). Phytoplankton
composition at the sampling site showed that Bacillariophyta was the dominant division
at Kg. Telaga Nenas, Perak while Cyfindrotheca was the dominant genus where it
dominated 6 out of 17 sampling months. The highest density of phytoplankton at the
sampling site was in October 2004 (4.981 ± 0.529 X 106 cell/l). However, 13 out of 17
sampling months showed low density of phytoplankton where the density was lower
than 1.0 X 106 cell/l. Low growth of C. iredalei were due to the lack of presence of
suitable dominant phytoplankton at the sampling site. Only 2 phytoplankton genera
(Chaetoceros and Skeletonema) which are suitable for C. iredalefs culture are
dominant throughout the sampling period. However, Chaetoceros is only dominant in 2
sampling months (June 2004 and January 2005) while Skeletonema is only dominant
in November 2004. Based on this findings it shows that Kg. Telaga Nenas is not a
suitable place for commercial culture of C. ireda/ei.
Description
Keywords
Persekitaran terhadap pertumbuhan , Kemandirian tiram komersil , Crassostrea iredalei (faustino) , Penternakan tiram , Kg. Telaga Nenas