International Journal of Marine Science, 2017, Vol.7, No.34, 344-352
347
Table 1 Seasonal variation in the mean values (Mean ±SD) of different abiotic variables of the sediments at the four different sites
Veraval
Sutrapada
Dhamlej
Kodinar
Sediment temperature (°C)
Winter
29.33±0.45
28.46±0.83
28.60±0.72
28.00±0.81
Summer
33.35±1.04
33.60±1.08
33.62±0.65
33.66±1.15
Monsoon
31.10±1.13
29.70±0.56
30.3±0.84
29.6±0.98
Sediment pH
Winter
7.76±0.15
8.05±0.15
7.96±0.05
8.06±0.20
Summer
8.25±0.17
8.32±0.22
8.32±0.09
8.35±0.17
Monsoon
7.50±0.14
7.50±0.15
7.75±0.21
7.55±0.35
Sediment salinity (%)
Winter
38.66±0.57
37.09±1.07
39.75±1.08
36.66±2.08
Summer
39.75±1.07
39.00±0.81
40.00±1.82
38.75±1.5
Monsoon
35.00±1.41
32.5±0.70
34.0±1.41
32.5±0.85
2.2 Biotic variables
There was a strong positive relationship between crab carapace width and burrow opening diameter (R
2
=0.95;
p<0.001, Figure 2). Burrow abundance of
O. ceratophthalmus
was recorded very low in the lower part of the
shore, which increased maximally in the mid part and then decreased slightly on the upper part of the shore at all
the sites (Figure 3B). Burrow diameter showed the opposite pattern, with increasing size towards the mid and
upper part of the shore at the study sites (Figure 3A).
Figure 2 Regression analysis for the relationship between crab carapace width and burrow opening diameter pooled for the four sites
throughout the year (n=45)
The density (Figure 4A) abundance (Figure 4B) and frequency of occurrence (Figure 4C) of
O. ceratophthalmus
burrows varied between different seasons and sites. Maximum density (Figure 4A) abundance (Figure 4B) and
frequency of occurrence (Figure 4C) of burrows were recorded at Kodinar followed by Sutrapada, Dhamlej and
Veraval in the monsoon season. The result of
Two – way ANOVA showed significant variation for the mean
values of the seasonal and site specific burrow density, abundance and frequency of occurrence of the species
(Table 2). Regression analysis between sediment temperature and burrow abundance of the
O. ceratophthalmus
did not show significant correlation at all the study sites. Sediment salinity also did not show significant
correlation with the abundance of the species for different study sites except Kodinar. Sediment pH showed
