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

Abstract

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 ~ 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.

When and Where Did They Strand? The Spatio-Temporal Hotspot Patterns of Cetacean Stranding Events in Indonesia

“…The lack of funding, insufficient knowledge and training for first responders and veterinarians, limited equipment and the lack of systematic data collection have been identified as obstacles to effective marine mammal stranding management in other developing countries [31,42,46,47]. Our analysis of the available stranding data in Indonesia concurs with that list, but several more issues have also been identified above.…”

“…To date, there have been some insights into the trends or management of marine mammal stranding events in developing countries such as Brazil, Chile, India, Mexico and, to some extent, Indonesia [20,31,42,46,47]. Our paper contributes to that growing body of knowledge and provides an update on the progress of the marine mammal stranding management in the country.…”

“…We conducted a cluster analysis [29] to determine if hotspot locations for individual and mass stranding events correspond to locations with high incidents in both time periods. The term 'hot spot', an area that has high occurrences compared to neighbouring locations, has been widely used, from biodiversity, to crime and emergency reports, forestry loss, disease outbreaks and marine mammal strandings studies [30][31][32][33]. By applying the fixed distance bands, the 'Optimized Hot Spot' geoprocessing tool used the Getis-Ord Gi* statistics to identify the areas of significant hotspots in three confidence intervals (90% CI, 95% CI, and 99% CI).…”

Spatio-temporal trends in cetacean strandings and response in the south-western Indian Ocean: 2000-2020

“…Temporal factors (e.g., breeding season, residency patterns, etc.) and anthropogenic pressures may partially explain the pattern of stranding events reported here (Jackson et al, 2015;Webster et al, 2020;Dudhat et al, 2022;Piwetz et al, 2022;Russell et al, 2022). The seasonal analysis revealed that strandings occur throughout the year, but the stranding peaks differed between mysticetes and odontocetes.…”

Short Communication: Pregnant dwarf sperm whale (Kogia sima) stranding in Palk Bay, India: Insights and significance of stranding records

“…Little is known about the occurrence of dwarf sperm whales in Indian waters, but there have been some recent efforts to document strandings, e.g., Dudhat et al (2022). Here we provide details of a stranded pregnant dwarf sperm whale, the first record of its kind in Indian waters.…”