Boring Pattern of Isopods in the Intertidal Hard Mud Substratum of Gulf of Khambhat, With Two New Records From Gujarat Coast

Abstract

The study of the burrowing and boring pattern is an important bioturbatory behavioral display that provides information about interactions of animals with their surrounding factors and habitat selection preferences. Previous studies have explored the boring activities of sphaeromatid isopods in a variety of substrates, including wood, polystyrene, and rock, across different regions worldwide. However, no previous reports have been documented on the boring pattern of isopods in hard mud substratum. Present studies were carried out on the silt-clay rich hard substratum of coastal mudflats at Kamboi, the northern innermost region of the Gulf of Khambhat, Gujarat. This habitat is selectively preferred by the isopod Sphaeroma annandalei Stebbing 1911, which is indicated by its abundance. To decipher the boring patterns, we examined the sediment blocks during low tides, took multidirectional sections of the exposed regions, and photographed the boring patterns. It showed that there were incidences of the bores of different sizes crossing each other. We primarily interpreted it as the borings of younger and older isopods. However, to further confirm, resin casting was done, which gave us a complex network of interconnected borings. It clearly exposed, for the first time, the continuous interconnected burrows of different sizes of individuals (0.56 mm to 4.75 mm) of S. annandalei in hard mudflat habitat. The study has recorded the presence of two species, S. annandalei and Cirolana willeyi Stebbing 1904, for the first time from Gujarat.