Signals from the sea: why sardines, jellyfish are washing ashore

Key points

• The Indian oil sardine has long sustained the livelihoods of coastal communities along the west coast.
• Thriving in the nutrient-rich waters driven by seasonal upwelling, these small but economically vital fish are now behaving strangely, washing ashore in large numbers along the coasts of Kerala, Karnataka and Goa.
• The fishermen community reports poor catches in the days following such strandings, signalling deeper disruptions in the marine ecosystem.
• Scientists at the Indian Centre for Ocean Information Services (INCOIS) here in Hyderabad, have now pieced together the reason behind this.
• Drawing on satellite data and ocean models, they have identified a web of interacting forces: marine heatwaves, coastal upwelling, ocean currents, tidal forcing and extreme weather events.