While unrest boils in Sri Lanka’s commercial capital of Colombo — where protesters over the weekend stormed the presidential residence and forced President Gotabaya Rajapaksa to announce his intention to resign — daily life has become a fight for survival.

Unable to find kerosene for their boats, nor afford it on the black market, fishermen have not ventured out for three weeks. Without their catches, families can only buy fish from the market at inflated prices — $7 a kilogram in nearby Jaffna. Locals say they are skipping one or two meals a day.

At the same time, Sri Lankan fishermen worry that their Indian rivals from the state of Tamil Nadu are exploiting their absence. These fears became more acute last Sunday, when the Sri Lankan Navy arrested 12 Indians and seized their boats for allegedly fishing illegally in Sri Lankan waters.

The fisheries industry contributes around 2.7% to the country’s gross domestic product, providing direct and indirect employment to more than 575,000 people. There are 50,000 fishing families in the four districts of Mullaitivu, Jaffna, Mannar and Kilinochchi, with roughly 15,000 operating fishing boats. Each boat needs at least 20 liters of kerosene to get out to sea and return the same day. Kerosene that once cost about 88 Sri Lankan rupees (24 cents) per liter was recently selling for 400 to 500 rupees a liter on the black market.

Appeals to the government for fuel have had little effect. The last consignment came in the first week of June, when India sent 15,000 liters of kerosene. This was rationed out, with workers complaining that it was not enough to meet even one district’s daily needs.

Adding to the resentment, the Sri Lankan fishermen believe India is maneuvering to regain the rights to Katchatheevu, an uninhabited island that India ceded to Sri Lanka under a 1974 maritime agreement. The waters around the island are rich in prawns and other valuable seafood.