Invasion of lionfish Pterois volitans and other reef fishes in the Vellar estuary, Parangipettai (lat. 11 degrees 29'N, long. 79 degrees 46'E) southeast coast of India, is a cause of concern as it may affect the local fishing communities and the estuarine ecological conditions. The present study reveals the temporal variations in the abundance of the reef-inhabiting fishes in the different estuarine locations (oyster beds, mangroves and bridge). A total of 184 individuals of lionfish were captured from the three locations during April-September 2011. Different size groups were caught (total length 6.8-17.8 cm) throughout the sampling period and captured individuals were more (n = 164) near the mangroves and oyster beds, than those (n = 20) found near the man-made structure (bridge). Percentage capture of lionfish was higher during August. Other reef-associated fishes were also recorded and the family Acanthuridae (n = 51) was dominant and the remaining taxa were less abundant. Twelve prey taxa were identified through gut content analysis of lionfish that includes penaeids, non-penaeids and teleosts. The dominant taxa were found to be the shrimps, indicating the colonization of lionfish in newer but natural habitat as feeding ground. The human-driven changes may facilitate the successful intrusion of reef fishes in the estuaries.
