Assessing the Effects of Ghost Nets on Coral Health: An Examination of Coral Reefs on Androth Island, Lakshadweep

Abstract

In our study, we investigated the impact of derelict fishing gear on coral reefs in various locations on the Androth reef of the Lakshadweep. We found significant variations in coral health across the surveyed sites, with some areas showing a high percentage of live coral while others exhibiting a high percentage of dead coral. Ghost nets snagged on reefs at all depths had a significant negative impact on coral health, according to pairwise analyses. Pearson's correlation analysis of coral health and stress relationships confirmed a significant relationship between ghost nets and coral health (LC, DC, R, and AA) at all sampled depths. In our analysis, we examined coral mortality, tissue loss, and variations in zooxanthellae density among different coral species. The average sedimentation ranges recorded monthly were 49.75 ± 43.2 and 116 ± 41.05, respectively. The sedimentation rate in the Androth reefs of the Lakshadweep was approximately five times greater than in the other regions. During our survey, we observed abandoned fishing gear, including 6 mm fishing ghost nets (28%), 5 mm fishing ghost nets (11%), ropes (31%), buoys (19%), and lines (11%) across the study sites. The overall composition of live coral cover on averaged was 22.1%, while dead coral accounted for 24.3% and rubble constituted 53.6%. Furthermore, we removed more than 48 kg of ghost nets from the NIOT underwater pipe, and significant quantities of these nets were retrieved from sites SW3 and SW2 (12.5 kg each) during our efforts. This study highlights the critical importance of addressing ghost net entanglement and its detrimental effects on coral health, as well as the urgent need for conservation efforts in the surveyed reef ecosystems.