Wood boring teredinid molluscs engulf most of the wooden particles scrapped by them while actively boring into wood, obtaining nourishment for their metabolic activities. In order to protect the wooden structures from the biodeteriorating activity of such organisms, the wood is treated with different chemical formulations to prolong their service life. Copper chrome arsenic (CCA) is one such wood preservative chemical offering excellent protection to wood under marine conditions. Field observations with CCA treated test stakes as well as actual wooden structures have, however, shown that they are not free from wood borer attack after considerable service life. The successful settlement and growth of these organisms are a reflection of their metabolic ability under such adverse chemical stress conditions. As copper and arsenic are known to be metabolic inhibitors, a study was undertaken to investigate the respiratory behaviour of Lyrodus pedicellatus (Quatrefages), the most virulent teredinid wood borer at Visakhapatnam harbour, East Coast of India. As a first step, experiments were conducted on this aspect under copper stress. The results show that in situ oxygen consumption of the animal under normal conditions was found to range from 0.8 – 5.6 μl.mg-1.hr-1 averaging 2.43 μl.mg-1.hr-1. Under acute toxicity of 0.5 ppm copper, the oxygen demand was observed to fall almost to half the normal levels (0.4 – 3.5 μl.mg-1.hr-1), but showed a gradual increase subsequently during the next 24 hours. However, when the stress was continued for 96 hours, the oxygen uptake gradually decreased again to 0.2 – 2.1 μl.mg-1. hr-1.

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