Similar to artificial offshore structures, natural structures such as an island also protect the low-lying shoreline and shape the pocket beaches. In the Gulf of Mannar, many long islands have formed protruding from shorelines. Formation of these indirect morphological structures depends upon a number of factors, such as the width of the island, offshore distance of the island to the morphological structure, supply of sediments and other geological conditions. The hydrodynamic conditions between Tuticorin Harbour and Van Island have changed because of various factors over the years. Van Island coral reef formation had attracted man-induced mining causing irreparable damage to the fragile ecosystem. The emerged natural breakwater and the submerged coral reef, together with the artificial breakwaters of Tuticorin Harbour, have been contributory to quantifiable change in hydrodynamic conditions around Tuticorin. As a result, the transmission of wave power to the shoreline has increased and the salient growth at Salaipatorri Point, Tuticorin, has started to recede. The bathymetric chart published in 1978 is used for all dimensions of Van Island and receding salient growth at Salaipatorri Point.

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