AQUATIC ANIMAL DISEASES AND INVASIVE SPECIES THREATS TO TROPICAL ISLAND ECOSYSTEM: ANDAMAN AND NICOBAR ISLANDS PERSPECTIVE

Aquatic animal disease surveillance is currently being conducted in Andaman and Nicobar Islands (ANI) to detect prevailing diseases and infestations. The study reported several new diseases and infestations, which proved that comparatively less number of diseases reported earlier might be due to lack of intensified research on aquatic animal disease surveillance in ANI (Table 1).

A serious issue concerning biosecurity to be addressed is the introduction of invasive species. Freshwater carp seeds were brought from the mainland India to meet out the local demand which had mainly contributed for the introduction of exotic fishes and amphibians which in turn became invasive in these Islands. Around 57 freshwater species were recorded during our survey reports of which 23 species were introduced and 34 species were native to these Islands. Besides, carnivorous invasive fishes such as catfishes, murrels, anabas and pacu also fetch very high market price and are in greater demand. The extent of invasive species could also be recorded in the remotest Islands such as Great Nicobar and Car Nicobar.  

Invasive species can offer a tough competition for food and niche with native species and pose a threat to the fate of biodiversity hotspot of Island ecosystem. Besides, invasive aquatic animals are accompanied with the risk of establishing exotic diseases in the Island ecosystem and local transportation of seeds may spread the disease among the  

Islands and perhaps collectively lead to the extinction of endemic species in near future. With this background, suggested measures to control the deleterious effects of invasive species in ANI are provided in Fig. 1.