Page 13 - IJMS-2014v4n66

International Journal of Marine Science 2014, Vol.4, No.67, 1-6
http://ijms.biopublisher.ca
5
waste, household and agriculture in the upstream.
Nevertheless, the effect has not shown a real change on
the distribution of the molluscs; they are only found at
one station that has a very high abundance of
pelecypoda, where the location of the station is in the
mouth of the river. Hence, it is assumed that the area
occurs accumulation of the very high pollutants
characterized by high rate of some environmental
parameter values such as multiple BOT with a range
from 21.98 to 52.78, low brightness with a range from
12.78% to 22.17%, the high turbidity with a range from
2.81 NTU to 7.25 NTU. However, some of the other
environmental parameters are still under optimal
conditions such as temperature with a range of 29.5 °C
to 31 oC, salinity with a range from 20 ‰ to 31 ‰, pH
with a range from 7.7 to 8.2, and oceanographic
parameters (Table 2).
The management of the habitat molluscs
Principal Component Analysis (PCA) of the three
classes of mulluscs and seven environmental
parameters having an impact on the habitat of the
molluscs diffuses in 20 stations. It points out that the
factorial axis is on four sides of the two factorial axes,
i.e., axis 1 and 2 (F1, F2), where each axis describes the
probative value based on the level of percentage, the
axis F1 illustrates the probative value of 37% and the
axis F2 explains 28% of the probative value of the total
variance. Thus, the total percentage of the probative
value is 65% (Figure 2). Principal Component Analysis
chart shows that the three groups of molluscs based on
each class are characterized by the different
environmental parameters.
Bivalves are characterized with a contribution of
+0.1571, which mean the habitat conditions for
Bivalves‘growth are very limited by salinity
fluctuations on the habitat. The range of the salinity in
the location of the observations is approximately
29-31‰. The range is a decent range for the growth
and survival of molluscs. In addition, the
environmental parameter, an identifier of molluscs’
survival, is the depth with contribution value is
+0.5284 with a range of 1.7 to 4.1 m. The other
environmental parameters such as temperature, pH,
BOT. turbidity, and stream show the contribution with
negative correlation in the range of -0.1460 to -0.5357.
The gastropods are characterized by a contribution of
+0.1084, which mean the habitat conditions of
gastropods’ growth are very restricted by salinity
fluctuations of the habitat. The range of the salinity in
the location of observations is approximately 29.5 to
30 o /oo. The gastropods are also individualized by pH
with a contribution of +0.5834, which signify that the
habitat conditions of the gastropods’ growth ranged
from 7.7 to 8.2. The organisms are also identified by
dissolved organic materials in the high contribution of
+0.0083 with a range of 31.2 to 52.1. Furthermore, the
environmental parameters that become the identifier
are turbidity with a contribution of +0.1730. In other
words, Gastropods’ life are limited in the turbidity
ranged of 2.81 to 7.25 NTU. The range is a proper
range for the growth and survival of molluscs, while
the other environmental parameters such as the
temperature, the depth, and the stream show a
contribution with negative correlation in range of
-0.0128 to 0.3313. Pelecypods are characterized by
turbidity of 4.4 to 7.25 NTU with a contribution of
+0.2069. It denotes that the habitat conditions for the
growth of Pelecypods are limited by fluctuations of
the turbidity. Moreover, the depth gives a contributes
of +0.3627 or of 1.2 to 3.5 meters, which mean the
habitat conditions for the growth of Pelecypods is a
decent range for the growth and survival of mollusks.
The other environmental parameters such as
temperature, pH, and stream indicate that the
contribution of the negative correlation is in the range
of -0.0148 to -0.5271 (Table 3 and Figure 3).
Table 3 Results of the principal component analysis on the correlation matrix and the contribution of environmental parameters on the
habitat of the molluscs
Environmental parameters Bivalvia Gastropoda Pelecypoda
temperature -0.2709 -0.3313 -0.0488
Salinity +0.1571 +0.1084 -0.5271
pH -0.3852 +0.5834 -0.0148
BOT -0.1700 +0.0083 -0.0690
NTU -0.5357 +0.1730 +0.2069
depth +0.5284 -0.3811 +0.3627
Stream -0.1460 -0.0128 -0.1389