Mémoire
| Résumé : | Coral reefs are crucial for marine biodiversity and coastal communities. However, they arethreatened due to anthropogenic pressure and climate change. Here we describe a bleachingevent observed during the warmest months of 2019 in an understudied reef-complex ineastern Sri Lanka. 5 sites in Kayankerni were monitored from 2017 to 2022. In 2019 two siteswere added in Pasikudah. The impact of the bleaching event was heterogenous: at 6 sitesbleaching was extreme: 60.2% to 96.7% of the coral cover bleached. In contrast, bleaching wasmild in one site (5.1 %). Recovery also varied: most colonies recovered by the end of thebleaching event at some sites, and by 2022 coral cover was equal to or larger than what wasfound in the pre-bleaching period. In contrast, sites that underwent relevant mortality duringthe bleaching event only recovered a fraction of their pre-bleaching coral cover. The fishassemblage remained relatively stable at some sites; others showed a rise in the number ofherbivorous fish during the bleaching event, and others showed a marked decline in theabsolute abundance of most fish families from the pre-bleaching period to 2022. Loss ofbutterflyfish (family Chaetodontidae) was reported from all sites, a decline that was sharper inthe most affected sites by the bleaching event. The decrease was more pronounced forobligate corallivores than for other butterflyfish. Research shows reefs in Kayankerni andPasikudah are susceptible to ocean warming but have potential to recover. Such resilienceshould be sustained through management actions. |
