Progress report for
Climate change caused bleaching and subsequent mortality in 2016 - post bleaching monitoring in Gulf of Mannar, Tamil Nadu, India
Achievement at a glance
Recovery in 2018: After the mortality in 2016, there was no or only minimal bleaching in 2017 and 2018. Catalyzed by this positive trend the corals started to recover gradually, from 22.69% in 2016, and coral cover increased to 24.76% in 2018. Fast growing coral genera Acropora, Montipora and Pocillopora were the first to recover from the bleaching impacts. Recovery was comparatively faster and more in the Tuticorin group (southern part of Marine National Park) where the live coral cover increased from 26.82 in 2016 to 30.12% in 2018; in Keelakarai group the increase in coral cover was from 26.24 to 27.58% between 2016 and 2018. Incidentally, the area cover of algae had increased significantly from 22.12% in 2015 to 36.11% in 2016, during which period corals sustained the bleaching-triggered mortality. However, algae cover was 30.66% in 2018.Bleaching in 2019: Corals started to bleach in April 2019 when the intensity of bleaching was comparatively low and the bleaching intensity increased only in May 2019. Massive corals like Porites sp., Favia sp. and Favites sp. were the first to be affected by bleaching, followed by the branching corals like Acropora sp., and Montipora sp. Temperature level was as high as 32.1 C during April 2019 causing widespread bleaching. The prevalence of bleaching was less than 4% during April and it increased upto 25% in May. Acropora formosa, A. intermedia, A. nobilis, A. cytherea, Montipora divaricata, M. hispida, M. foliosa, Porites solida, P. lutea, Goniastrea retiformis, Platygyra lamellina, Favia sp. and Goniopora sp. were the coral species affected by bleaching in 2019. However, there was fall of temperature by the end of May, and there was no mortality. The bleached corals have also recovered slowly.
Challenges faced in implementation
The coral mortality due to bleaching in 2016 helped in the increase of algal cover, and sponges too flourished in Gulf of Mannar. The bleaching in 2019 had slowed down the coral resilience in Gulf of Mannar, though it did not cause any mortality.Beneficiaries
The beneficiaries are mainly the poor local small-scale fishers as the monitoring data will help to take appropriate remedial measures by the conservation agency in order to maintain the health of coral cover so that there will good fish production and diversity.
The monitoring data will also benefit researchers, conservation managers and policy makers in taking considered actions to protect corals from the climatic and non-climatic impacts.
Actions
The data collected by continuous monitoring are reported to conservation managers and policy-makers in order to take action to protect corals from natural and anthropogenic impacts. This would benefit the local fisher community and also support the ongoing conservation initiatives through the development of appropriate response and management plans.As a first of its kind initiative in India, the data have helped in the development of Indias Coral Bleaching and Disease Response Plan in support of coastal fisheries and livelihood by SDMRI as a part Ministry of Environment, Forest and Climate Change, Government of India Programme.