Reading a Changing Sea

The sea doesn’t disappear all at once. It retreats slowly, quietly, until one day the docks feel too still. For India’s coastal fishing communities, that slow retreat is already underway. The sea is changing: warmer, less predictable, and increasingly unkind to those who know it best. What happens when the sea changes faster than the people who depend on it can adapt?

I have lived along the coast all my life. The sea has been the one constant, the thing I orient myself with, the smell that means coming home. The fish markets, the docks, the boats going out before dawn; these were just part of the landscape I grew up in. On a recent visit to the docks, something made me pause… Fewer boats than I remembered. Not dramatically fewer, nothing so sudden. It was the kind of reduction that sneaked up on you, and things gradually became normal before you noticed they were ever different. That stillness at the dock made me wonder, which sent me looking for answers

India’s coastline runs approximately 11,000 kilometres, and every stretch of it is home to a community that has read the sea like a rhythm for centuries. The Mukkuvas of Kochi, the Kolis of Mumbai, and the Jalaris of Vizag are not just fishermen but living repositories of wisdom. They know which wind brings the rain and which current carries the sardines. This fluency has been passed down so long that it doesn’t feel like information anymore. It is instinct, but the sea, those instincts were built for, is not the same sea anymore… Rising water temperatures, erratic monsoons, and disrupted fish migration are quietly dismantling what generations built.  

The Indian Ocean, specifically, has been sounding alarm bells since the early 2000s. The Indian National Centre for Ocean Information Services (INCOIS) has issued marine heatwave alerts across six basins, including the Arabian Sea, which lines the entire western coast, the most recent in April 2026, its most widespread alert yet. The world’s oceans absorb nearly 90 percent of the excess heat trapped by greenhouse gases, and the upper layers are warming at a rate with no historical parallels, though marine heatwaves don’t announce themselves with drama. They are invisible upheavals. The coral reefs bleach, plankton dynamics shift, and fish crucially move. They migrate to cooler waters, away from where the nets are, away from where the boats go.

The Central Marine Fisheries Research Institute (CMFRI) in Kochi, for instance, went directly to the fishing communities. What the fishermen noticed was stark: an average of six species had simply vanished from their usual catches. Not shifted… not reduced… but gone from the nets entirely. The study mapped this district by district, finding declining fish populations across most of Kerala, with fishermen in Thiruvananthapuram and Alappuzha reporting particular difficulty predicting wind patterns and safe fishing windows. In Ernakulam, the crisis has precipitated a loss of workdays and falling income. The data added another dimension: fishing days in Kerala fell by 46 percent following Cyclone Ockhi in 2017. The communities weathering the sharpest consequences of a warming ocean are almost entirely unprepared for it.

When catches fall and fishing windows become unpredictable, the first thing that shifts is the work itself. Many have started to move into allied trades: boat repair, fish vending, and loading work at the docks. The National Innovations in Climate Resilient Agriculture (NICRA), a project initiated by the CMFRI, to address the slow erosion of livelihood and to build practical capacity. They focused on what rising sea temperatures mean for fish distribution and what fishermen can realistically do differently. On the ground, this translated into ice boxes for fisherwomen to extend the shelf life of catch in warming conditions, along with the provision of gillnets, cast nets, and seabass seeds to widen what communities could harvest.  

Whether these interventions have been enough is difficult to gauge. Initiated in 2024, the NICRA project in Ernakulam remains a localised effort, its reach too limited to draw broader conclusions. What is clear is that an ice box extends the shelf life of a catch; it does not restore the catch itself. Seabass seeds and cast nets diversify what a community can harvest, but they do not replenish the species that have already gone from the nets. These are thoughtful, ground-level responses to an immediate crisis. However, the gap between what is being done and the scale of disruption remains wide. Which brings the question back to the coastline, all 11,000 kilometres of it.

Kochi is one city, the Mukkuvas one community, and the Arabian Sea one basin among many that are warming; fishing communities all across the coast are navigating a sea that is behaving differently. Indian fishing communities collectively represent millions of livelihoods. However, the policy infrastructure around them — insurance coverage, early warning systems, climate adaptation support, among others — has not kept pace with the changes. CMFRI’s work in Kochi points towards what a more complete, cohesive response could look like: research that listens to fishermen, interventions that meet communities where they are. What remains to be seen is whether the solutions being implemented can keep pace with the urgency the situation demands.

-Written by Aarushi Senthil Kumar, Research Fellow, CCF