Thankachan Polayalil has been a fisherman for 42 of his 65 years, long enough to remember when fish were visible from land, brimming just beyond the palm trees of the Malabar Coast.
Now his boat is equipped with an echolocation machine, but fish still are hard to find – and the catch isn't nearly as diverse. The anchovies are gone, and the mackerel now often swim in deeper water, making them harder to snare.
Joy Valiaparinb, another fisherman at Chellanam Fishing Harbour, said he regularly pushes off at 2 a.m., knowing it can now take hours just to spot fish.
Often, according to fishermen along India's southwestern coast, they find nothing.
Climate change is making an already difficult search for fish harder, according to scientists at the Central Marine Fisheries Research Institute (CMFRI) in the nearby city of Kochi.
Fish populations are always shifting, sometimes drastically, and overfishing has emptied waters once teeming with life, they said.
But as climate change has warmed India's coastal waters by more than half a degree Celsius over the past three or four decades, scientists say, fish populations have sought cooler waters - often away from where fishermen are used to finding them.
That has forced fishermen to spend even more on nets, fuel and ice to keep fish fresh as they spend more time at sea.
They stay afloat only because fish prices are rising as shortages grow, and they can find a market for almost anything that shows up in their nets, they say.
Sardines on the move
On a January morning, the Chellanam Fishing Harbour beach is strewn with silvery oil sardines piled into red and yellow baskets.
It's evidence of a good catch, something now relatively rare. Traders heave boxes of fish into the back of yellow trucks, to set off on the jostling journey to buyers.
Fishermen say sardines are a favourite because the fish is popular and relatively affordable for buyers.
"Even if other fishes are there, (fishermen) always say if oil sardines aren't there, there is a shortage of fish," said P.U. Zacharia, a CMFRI principal scientist with expertise in climate change and marine fisheries.
Oil sardines used to swim in India almost exclusively around the Malabar Coast - but climate change has pushed them east and northeast, into waters around Mumbai and Kolkata, scientists say.
Fish all over the planet are migrating toward the globe's poles, often seeking the cooler water they are used to as the ocean warms, the scientists say.
With buyers in Mumbai, Gujarat, and West Bengal not as used to eating oil sardines, the fish caught there are often shipped south, losing value and freshness in transit, Zacharia said.
Fishermen are also struggling to catch mackerel, another long-time staple. More mackerel are now found at depths where the water is cooler, forcing fishermen on days-long trawling operations that require expensive nets, more manpower, more fuel, and more ice to keep the fish fresh.
One fisherman, from the coastal city of Kanyakumari, said fuel for an average trip has risen from around 70,000 to 200,000 rupees ($980 to $2,800) over about the last seven years.
Mijeesh Xavier, a fish trader along the Malabar Coast who serves as a middleman between fishermen and buyers, says he has felt the sardine shortage in rising prices.
As other traders showered boxes of sardines with crushed ice, he said that just three or four years ago a box of the fish went for 1,500 rupees ($20). Now, he said, the same box costs 5,000 rupees ($70).
The Malabar Coast's oil sardine catch declined through the 1970s and 1980s, according to data provided by Zacharia. It rebounded in the late 1990s, but has again fallen since 2012.
Finding a way forward
When fishermen throughout India pull up a trawl net, about 15-20 percent of what they get is considered "bycatch" – less valuable species they weren't looking for, according to CMFRI principal scientist Shyam Salim, who has studied climate change and vulnerability in India's coastal communities.
But with more valuable species disappearing, the market for bycatch is expanding, he said.
"Now there is no fish being wasted," Salim said. "Everything which lands will be getting a small value or another."
Fishermen often sell bycatch to be ground into animal feed, and higher fish prices have helped many fishermen maintain their income, Salim said.
The unlucky ones have been forced to buy food, nets, and new boats with loans from money lenders that they then struggle to pay back, according to National Fishworkers Forum General Secretary Thomas Peter.
Fishermen in Kerala mostly don't have other skills to bring in an additional income or to land another job, Salim said, though some are farming fish for extra money.
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As of 2016, according to Zacharia, the number of regional fishermen had fallen to 130,000 from a height of 145,000.
The younger generation has skills their parents lack, and many have bypassed the industry for white collar jobs in the city, Salim said.
To help fishermen get through the year, the government now provides supplemental food during the monsoon season when trawling is banned, he said.
Fishermen can also earn income through a yearly program in which the state and central governments match savings contributions fishermen make.
Hoping to help fishermen adapt to changing conditions, CMFRI scientists are beginning to model the ways climate change may influence the movement of sardines, mackerel, and several other species in decades to come.
They hope their models will predict the size and species of future catches so fishermen will know what to expect.
But as increases in climate-changing emissions drive higher temperatures, fisheries are likely to see continuing change, scientists warn.
"I think there will be no such thing as an equilibrium," said Gretta Pecl, a climate change ecology specialist at the University of Tasmania. "Not for our lifetimes."