Surviving in a warming and crowded world: a review of Irrawaddy dolphin in Asia’s largest brackish water lagoon

Abstract

In human-altered environments, wildlife is impacted by a range of factors; therefore, understanding on responsible factors can aid in developing conservation strategies. Irrawaddy Dolphins (IRD: Oracella brevirostris) are a group of cetaceans listed as highly endangered species under - threatened species red list of IUCN. A subpopulation of IRD is found in Chilika lagoon, a brackish-water ecosystem in the eastern seaboard of India, which is also the single largest habitat of IRD in the world. They are survived by only a few hundred individuals in small pockets in Chilika and are therefore given maximum protection under the Indian Wildlife Protection Act (1972), but much remains to be done for their conservation as they have not drawn enough investigation. This article comprehensively synthesizes existing literature on IRD, has established linkages between their behavior and physiology with threats (both climate-driven and anthropogenic), and has finally laid down a conservation and management roadmap to safeguard their future in Chilika. Damming and diversion of rivers opening in Chilika, unsustainable dolphin watching tourism, pollution, and net entanglement are some of the prominent threats faced by IRD in Chilika. Predicted climate change scenarios such as potential warming of the lagoon, increased littoral drift, sea level rise, and increased frequency of cyclones would exacerbate their survival crisis. It is also emphasized that the conservation strategy of IRD must be moved from species-centric to ecosystem-based for their long-term sustenance.