Fishes of Lakshadweep archipelago: new records, review and a revised checklist

Extensive studies on fish diversity in Lakshadweep waters began with Jones and Kumaran’s in 1964. Reports after these authors were sparse and sporadic until the turn of this century. Although recent reports have increased the tally, targeted studies are lacking, and there is a possibility of listing more species for this region. Studies on the diversity and abundance of fishes are due, given the atoll system undergoing rapid changes: structural decline due to several bleaching related coral mortality events, changes in the seagrass meadows, and the increase in fishing reef-associated species. These circumstances call for a revised checklist of fishes for this region, for the latest dates back to 1991. Thus, we present an inventory of ichthyofauna of Lakshadweep atolls based on published literature and incorporating 15 new species records identified through a rapid survey. The new species records for this region are presented here with the diagnostics of these species. The checklist shows 856 species of 432 genera, 43 orders, and 144 families known from these islands, including 16 freshwater forms. 49.3% of the contribution is from 14 fish families having > 15 species each, while the remainder 131 families contributed 52.5%, which have < 15 species. About 154 species belonging to 12 families are known to contribute to the commercial fisheries of these islands. The new records reported in this work for this region are found in the Maldives, and Sri Lanka proves the zoogeographical affinity of these two regions with the Lakshadweep archipelago.

Two new Pseudoceros (Platyhelminthes: Polycladida: Pseudocerotidae) from Agatti Island, India and a species checklist from Indian waters

The Lakshadweep archipelago constitutes a major coral region of India but still lacks sufficient biodiversity data owing to its remoteness and a low number of faunal studies in the past. The present paper describes two new Pseudoceros species collected from Agatti Island, Lakshadweep, India. Pseudoceros bipurpurea sp. nov. and Pseudoceros galaxea sp. nov. are described based on external and internal characters, supported with histological studies and photographs. Pseudoceros bipurpurea sp. nov. is characterized by a cream background colour and an orange median line surrounded by dense patches of purple spots, which tend to disperse and broaden towards the posterior end. Pseudoceros galaxea sp. nov. displays a brown background colour with numerous white to cream dots covering almost the entire dorsal surface and a thin black margin. This study adds two new species to the polyclad fauna in Indian waters, raising the count to 68 species. An updated checklist of polyclads from Indian coast is also provided.

Composition and behavior of mixed-species foraging groups of reef fish in the Lakshadweep islands, India

Mixed-species foraging groups of reef fishes, although relatively common in occurrence, have historically received little attention. Most studies on this topic have been descriptive accounts of specific associations. In this study, we collected data on mixed-species foraging groups seen in the Lakshadweep islands, resulting in a dataset of 1289 groups. Data was collected from both reefs and lagoons of three islands (Kadmat, Kavaratti, and Agatti) within the Lakshadweep Archipelago over a period of three years. Cluster analysis revealed nine categories based on species composition in groups: parrotfish, juveniles, surgeonfish (small), surgeonfish (large), Anampses spp., wrasses, Parupeneus macronema, Parupeneus barberinus, and other goatfish groups. The clusters are named based on the nuclear species or most frequently seen species within the groups. These groups are distinct not only in terms of composition but also other parameters such as behavior (shoaling or attendant groups), habitat affinity, and group cohesion. Groups comprising herbivorous species such as parrotfish and surgeonfish were almost entirely shoaling in nature (large groups without nuclear individuals), whereas goatfish and wrasses tended to form smaller attendant associations. Groups also occupied different habitat types; for example, parrotfish and P. barberinus groups were seen mostly in lagoons while surgeonfish, wrasses, and P. macronema groups were more abundant on reefs. Our findings suggest that mixed-species foraging groups in fishes are comprised of distinct compositional categories that vary in behavior, cohesion, and habitat affinity.

Incursion of the killer sponge Terpios hoshinota Rützler & Muzik, 1993 on the coral reefs of the Lakshadweep archipelago, Arabian Sea

Our study documents the outbreak of a coral-killing sponge Terpios hoshinota in the coral reefs of Lakshadweep archipelago and highlights that it has further extended its territory into the isolated atolls of Arabian Sea and maybe a growing threat to the existing coral reefs in the region.