Spatio-temporal analysis identifies marine mammal stranding hotspots along the Indian coastline

Marine mammal strandings provide vital information on species' life histories, population health and status of marine ecosystems. Opportunistic reporting of strandings also serve as a powerful low-cost tool for monitoring these elusive mammals. We collated data over similar to 270 years available through various open access databases, reports and publications. Annual strandings along the Indian coast (mean =11.25 +/- SE 9.1) increased in the last two years of the study (2015-2017, mean = 27.66 +/- SE 8.5 strandings/year). We found that stranding events spike during June-September along the west coast and during December-January along the east coast. We identified several sections of the coastline, such as Mumbai (0.38 strandings/km), Kozhikode (0.28 strandings/km), Tuticorin (0.4 strandings/km), Rameswaram (1.82 strandings/km), Chennai (0.32 strandings/km) and Bhubaneshwar (0.26 strandings/km) with a higher number of stranded animals reported. Emerging Hotspot Analysis located new and consecutive hotspots along the north-west coast, and sporadic hotspots along the south-east coast. We recommend establishing regional stranding response centres at the identified hotspots coordinated by a National Stranding Centre with adequately trained personnel and central funding support. Regular stranding response training programs for field veterinarians, and frontline personnel of State Forest Departments near stranding hotspots would provide an improved understanding of marine mammal health and threats in Indian waters. Further, the suggested National Stranding Centre needs to maintain a 'National Stranding Database' for long-term marine mammal conservation planning in India.

Automated summary

Marine mammal strandings provide important information on species' life histories, population health, and the status of marine ecosystems. The study analyzed data over 270 years and found an increasing trend in strandings along the Indian coast. Peak stranding events were observed from June to September on the west coast and from December to January on the east coast. Several sections of the coastline were identified as hotspots with higher numbers of stranded animals reported. The study recommends establishing regional stranding response centers at these hotspots and maintaining a national stranding database for long-term marine mammal conservation planning.