Amid increasing instances of whale stranding, a research response team from the ICAR-Central Marine Fisheries Research Institute (CMFRI) has embarked on a 100-day coastal survey to better understand the diversity and distribution of marine mammals on the Indian coast.
The survey is a continuation of a joint research project with the Fishery Survey of India under the Ministry of Fisheries aimed at assessing marine mammal stock and population in Indian waters.
The researchers, who began the survey from Kochi, will study the marine mammal diversity on the Indian coast within 12 nautical miles and analyse the relation between stranding events and changing climatic conditions, said a communication here.
Conservation measures
They will also engage in habitat modelling and recording of stranding events, considering the potential impacts of climatic and oceanographic conditions on the biological dynamics of marine mammals. The collaborative project also aims at achieving a holistic understanding of marine mammal behaviour, population dynamics and ecology, setting the stage for effective conservation measures.
Scientists believe that climate change and the ensuing impact on ocean ecosystems might be one of the reasons for the increased whale stranding. Recently, the carcass of a 50-ft blue whale was washed ashore in Kozhikode. The increased frequency of cyclones and storm surges could potentially lead to such stranding. However, there is a critical need to study the impact of these extreme climatic events on behaviour and distribution patterns of marine mammals, the communication said.
Highly sensitive
These species are highly sensitive to both biotic and abiotic environmental factors, including habitat changes, shifts in distribution, alteration in migration routes, and climatic conditions such as rising ocean temperatures, changing cyclonic patterns and storm surges. Factors such as bycatch, underwater noise pollution, and injuries resulting from collisions with ships or boats are also significant contributors to marine mammal standing. These issues can significantly impact the reproductive success and survival rate of marine mammals.
R. Ratheesh Kumar, principal investigator of the project, said the CMFRI team would closely monitor such occurrences at sea and collect data on these for further analysis.
The CMFRI had initiated a marine mammal assessment project in 2021, during which 16 species were recorded through on-board visual surveys within the Indian Exclusive Economic Zone, including different species of whales and dolphins. After a temporary hiatus, the project was resumed in 2023. The survey employs the line transect methodology, primarily involving the sighting and species-level counting of animals.
