Indian mackerel (Rastrelliger kanagurta) is one of the major small pelagic fishery resources in India and the most important mackerel in terms of bulk landings and with a pan-India distribution along coastal waters of the Indian Ocean and West Pacific (FAO 2016)(Rohit et al. 2024). Previous studies seemed to indicate that no morphometric differences were found between the SW and the SE Indian coasts considering the existence of a unique stock (Remya et al. 2014) although further genetic studies are needed to complement this conclusion. It was also concluded that a Southeast Asia population surrounding the Indonesian-Malaysian archipelagos (South China Sea, Strait of Malacca, Sulu Sea, Celebes Sea, Andaman Sea) and an Iranian population (western Indian Ocean) exist but more samples should be gathered in the western Indian Ocean to have a clear evidence of the stock structure in the region (Akib et al. 2015). Finally, a recent study was able to differentiate the populations of Indian mackerel from the Arabian Sea, Bay of Bengal, and Andaman Sea using geometric morphometric analysis (Kasinath et al. 2024).

For the specific region covered by this profile, one other study, reported morphometric differentiation between two groups from the north and south regions of the western Indian coast albeit concluding that the Indian mackerel exists as a single stock along the west coast of India, and the observed differentiation was induced by a reduced intermixing of populations of distant locations (Sajina et al. 2011), which is in line with other study reporting one single unit in this region based on phenotypic features (Remya et al. 2014). Given the uncertainty regarding the Indian mackerel stock structure along the Indian coast, the profile was here structured based on the currently implemented statewise stock assessment method (Mini et al. 2023).