International Journal of Marine Science, 2016, Vol.6, No.11, 1-10
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2.3 Statistical analysis
The Pearson correlation coefficient was calculated to establish the relationship between carapace lengths of the
crab and different morphological parameters of the burrow cast. The mean values of various morphological
characters of burrow cast were also compared using paired t test. All the statistical analysis was carried out using
PAST statistical package.
3 Results
3.1 Burrow structure
A total of 55 intact burrow casts were obtained of which the host crab was captured for 38 times (28 males and 10
females). Total 8 different types of burrow shapes were recorded which include single tube burrow (15 burrow
cast), J shape with branch at the base (12 burrow cast), J shape (7 burrow cast), bulb shape (6 burrow cast), Y
shape burrow (4 burrow cast), multi branched burrow (4 burrow cast), Y shape with double opening (4 burrow
cast) and U shape burrow (3 burrow cast) (Figure 2). The crab carapace length showed significant correlation with
burrow opening diameter (r = 0.89, p < 0.001) (Figure 3a), burrow volume (r = 0.55, p < 0.001) (Figure 3d) and
burrow total length (r = 0.57, p < 0.001) (Figure 3e). The crab carapace length did not show significant correlation
with burrow depth (r = 0.24, p = 0.07) (Figure 3b) and burrow inclination angle (r = 0.03, p = 0.80) (Figure 3c).
Figure 3 Pearson’s correlation coefficient and regression values for the relationship between crab carapace length and burrow
opening diameter (a), burrow depth (b), burrow inclination angle (c), burrow volume (d), and burrow length (e).
