Reef and reef fish responses to climate change

Project timeline: 1998 - present

The 21st century began with a major coral bleaching event, triggered by elevated temperatures, that led to the functional collapse of coral reefs worldwide. These reefs, often compared to terrestrial rainforests, play a crucial role in shaping their environments, providing essential regulatory and provisioning services to human societies along coastal and oceanic regions. The decline of coral reefs due to climate change is a significant concern. After a bleaching event, both corals and reef fish populations see dramatic declines, but their recovery is complex and unpredictable.


Since 1998, a long-term monitoring program in the Lakshadweep has been the foundation of ongoing reef-related research.

Project objectives:

• Continue our long-term monitoring of the reef ecosystem in response to climate change

• Document the impact of climate change on corals, coral reef fish, concurrent recovery patterns and the implications these patterns have on the functioning of the reef

• Use previously observed data to describe how reefs behave and which processes play an important role in mediating recovery and resistance in reefs

Since the inception of this programme, our observations have spurred inevitable questions of understanding the mechanism that drives these patterns and observations. From studying the role of coral recruits in colonising barren patches of reefs to quantifying the role of herbivorous fish in mediating coral recovery, each component has furthered our understanding of the ecological mechanisms that are at play within the reefs of Lakshadweep. 

In an effort to collectively analyse our observations, we are now taking a bird’s eye view of this ecosystem to identify how the reefs recover and resist the impacts of disturbances.

Timeline: 2022 - present

Coral bleaching occurs due to the breakdown of the symbiotic relationship between coral polyps and algae called zooxanthellae. The process of coral bleaching results in the expulsion of the zooxanthellae, and the consequent whitening of the coral. Global temperature anomalies such as El Nino Southern Oscillation events can cause mass bleaching events across the world. In the face of climate change, such mass bleaching events are becoming increasingly common, and are perhaps the biggest threat coral reefs worldwide currently face.

However, not all coral reefs bleach to the same extent, and research over this past decade has been dedicated to finding pockets of resistance to bleaching which may serve as coral refugia. For instance, coral living in highly variable thermal environments like the Red Sea and Rowley Shoals, have shown a greater degree of resistance to bleaching.

In Lakshadweep, the lagoons are highly enclosed, shallow spaces of water – which could lead to greater diurnal variability in temperatures as opposed to the outer reefs that encircle the atoll. Given the acclimation and adaptation potential of coral in high-stress environments, it is possible that certain sites within lagoons could host populations of more heat resistant corals.

Project objective:

• Evaluate the relative susceptibility of coral in the lagoon and outer reef towards thermal stress

• Identify potential local-scale coral hotspots that are resilient to higher temperatures