Seasonal variation in the abundance of wood boring molluscs in Vellar estuary, southeast coast of India

Abstract

Wooden blocks of Mangifera indica, each 30 x 5 x 5 cm in size and 650 cm^ surface area, were exposed in the tidal zone of the Vellar Estuary at various positions from January 1981 to December 1981. The season of the settlement of wood-boring molluscs was determined by exposing the blocks for 1 month at a time, and the rate of growth and the dominant borers were studied by exposing the blocks for 3 to 12 months. Martesia striata Linne, Teredo furcifera von Martens, Bankia carinata (Gray), Bank/a campanellata Moll and Roch and Lyrodus pedicellatus Quatrefages were the common species encountered in the test blocks. Intensive settlement was seen during Summer (Aprii-June) and post Monsoon (January-March) periods.