Mixed-species groups of herbivorous reef fish show variable responses to ecosystem perturbations in the Lakshadweep Islands, India

The Lakshadweep islands, located 200-400 km off the west coast of India, are an archipelago of atolls and small islands, located on the Laccadives-Chagos ridge. This study was carried out within the lagoon and in the reef areas of three of islands within the archipelago, namely Kavaratti, Kadmat, and Agatti. Mixed-species groups were sampled between the months of October-April over the course of three field seasons; 2012-2013, 2013-2014, and 2014-2015. A total of 45 sites were sampled during each year of the study: 15 at each island, with 5 each in the lagoon and in reefs on the eastern and western aspects of the islands. The depth of the sites in the reef ranged from 12-18 meters, and sites in the lagoon ranged between 0.5 to 2 meters. Sampling was conducted using SCUBA in the reef and by snorkelling within the lagoon, between 8 a.m. to 2 p.m. Groups were sampled using a 60-minute random-walk at the three study islands. The local species pool of fish was sampled by visual census using timed belt transects.