R. Kiruba Sankar

Wetlands of Small Island Nations in South Asia vis-à-vis the Mainland and Island Groups in India: Status and Conservation Strategies

The wetlands of small island nations in South Asia such as Sri Lanka and the Maldives are compared with that of India with respect to their status, biodiversity, threats and conservation measures. Sri Lanka has diverse coastal habitats, which are known to support fishes (1800 species), marine turtles (5 species), marine mammals (38 species), corals (183 species), mangroves (40 species), birds (100 species), reptiles (33 species) and seagrasses (10 species). The Maldives boasts one of the world’s richest marine biodiversity comprising 250 species of corals, over 1200 of reef fishes, 200 species of sponges, over 1000 species of crustaceans and over 100 species of echinoderms. Marine biodiversity of India comprises 12,913 species, of which more than 5800 species are reported from Andaman and Nicobar Islands. Marine biodiversity of Lakshadweep islands is represented by corals (172 species), fishes (396), sponges (95), molluscs (260), echinoderms (84), crustaceans (80), turtles (04), birds (142), marine mammals (6), seagrasses (07) and mangroves (03). The major threats to these wetlands of South Asian countries are climate change, extreme events like tsunami, coastal erosion, population pressure, habitat destruction and over-exploitation. The chapter emphasises the need for adopting frontier tools for biodiversity documentation and innovative strategies for their conservation.

New record of the pantropical seagrass Halophila decipiens Ostenfeld (Hydrocharitaceae) from the Andaman and Nicobar Islands, India

Abstract The pantropical seagrass Halophila decipiens (Hydrocharitaceae), representing a new record for the Andaman and Nicobar Islands, was reported from two locations: Scissostris Bay of Port Blair at 6–7 m deep and Nursery of Neil Island at 10–12 m deep. Observations on the reproductive and vegetative characters indicate that the flowering plant is monoecious, has a pair of petiolated leaves with a hairy surface and serrated leaf blade margins with 5–9 cross leaf veins. Leaf morphometric characters varied significantly between the two sites. The leaves of the Scissostris Bay specimens were smaller (1.11×0.4 cm) than the leaves of the specimens from Neil Island (1.73×0.59 cm), which might be due to the deeper depth ranges at Neil Island or other environmental factors. The present record is the 11th seagrass species from the Islands and this species could have been overlooked due to its habitat in deeper water.

Investigation and confirmation of white spot syndrome virus (WSSV) infection in wild caught penaeid shrimps of Andaman and Nicobar Islands, India

White spot syndrome virus (WSSV) is one of the most prevalent, widespread and devastating pathogen associated with shrimp population. The present study was aimed at screening the wild caught shrimps from Andaman and Nicobar Islands (ANI) for WSSV infection. Shrimp samples of different penaeid species including Penaeus monodon, Penaeus indicus, Penaeus merguiensis and Metapenaeus monoceros collected from nine different landing centers across the coast of ANI were screened for WSSV infection. Presence of white spots, a typical clinical sign of white spot disease was observed on the exoskeleton of WSSV infected shrimp samples. Out of 241 shrimp samples, 39 samples of P. monodon were found positive for WSSV by nested PCR. Histopathological examination revealed eosinophilic to basophilic intranuclear inclusion bodies in gill tissue which are typical characteristics of WSSV infection. Nucleotide sequence of WSSV isolated from ANI showed 100% identity to the sequences of WSSV reported from Thailand, Taiwan, China, Egypt, Mexico, Korea, France and 99% identity to WSSV reported from India. The detection of WSSV in wild P. monodon of ANI further confirms the virus spread and biogeography.

Wetlands of Tropical Islands under Changing Climate: A Case from Nicobar Group of Islands, India

Wetlands have significant value to the tropical islands owing to their significance in terms of biodiversity, coastal protection, and economic values. This chapter highlights the impact of climate change on the wetlands of tropical islands, with Nicobar group of islands in India as a representative case. Nicobar has a prominent tribal group practicing community living by gathering resources available from the terrestrial and coastal waters. The islands are vulnerable to sea level rise and extreme events such as tsunami, earthquake, and cyclones that affect their routine life. The receding arable and forest areas also affect their livelihood. The projected changes in mean temperature and precipitation for Nicobar region indicate that the rainfall pattern is all set to change significantly during different seasons and the pattern of change in Nicobar would be different from that in Andaman. The magnitude of climate vagaries is likely to be more prominent in the years to come. This chapter illustrates the vulnerability of tropical island ecosystems in general and the Nicobar Islands in particular, to changing climate and calls for incorporating sea level rise into coastal planning and development of appropriate decision-support systems for taking adaptive action, in order to mitigate the impacts of climate change on these islands and their wetland ecosystems.

Growth and survival of marine sponges, Stylissa massa (Carter, 1887) and Liosina paradoxa (Thiele, 1899) in sea and land based culture systems

Two species of marine sponges Stylissa massa and Liosina paradoxa were cultured in cages (in situ) and in land based aquaria (ex situ) over a period of 120 days. Growth and survival were evaluated using four substrates viz., tile, block, coral rock and rope) under both in situ and ex situ conditions. L. paradoxa in cages recorded significant increase (p<0.05) on day 90 i.e., by 70% compared to initial volume whereas at 120 days there was a significant (p<0.05) decrease (54.22%). S. massa showed significant increase (p<0.05) in growth by 95.6% at 120 days compared to initial volume. Negative growth was recorded in S. massa under aquarium conditions while L. paradoxa recorded good growth as well as survival and performed exceptionally well in aquarium during the entire experimental period of 120 days. In cages, 90.62% survival was recorded for S. massa in 120 days. Among the different substrates used, coral rocks gave 100% survival whereas other substrates such as tiles, blocks and ropes showed 87.5% survival. Under aquarium conditions, S. massa showed overall survival of 81.25% and among the different substrates, 100% survival was obtained with coral rocks, 87.5% with blocks, 75% with ropes and the lowest survival of 62.5% was recorded with tiles.