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Not too long ago, the oil sardine was A Ilavarasu’s main catch. A country boat fisherman from Rameswaram, he says it is no longer the case although he recalls with optimism that three weeks ago his uncle netted a mini-bonanza of the fish, which he sold for Rs 5,000.

Out of the more than 750 marine animals that form part of fish landings in the eastern and western coasts of India, the oil sardine has been and still continues to be either the most or the second most numerous. In Rameswaram, the oil sardine season between December and March has been like the Diwali bonus of a salaried worker – a time that the fisherman would cite to his creditors, promising them that come “pechalai”, he will pay off all his debts. Researchers say that its presence in fishing nets is as much to do with fish breeding vagaries as it is about climate change and overfishing.

Story of migration
The oil sardine lives only for two and half years. On the eastern coast, it breeds on the sea off Chennai at a depth of 20 metres to 30 metres, research has shown. On the western coast, mid- and southern Kerala coasts are the breeding grounds. In the period 1985 to 1990, oil sardines were abundant off Chengalpattu, Cuddalore and so on. While in 1985, the oil sardine catch was some 4,270 tonnes as per the Central Marine Fisheries Research Institute (CMFRI), it grew nine times to touch nearly 38,000 tonnes in 1990. In the following years, the oil sardine catch began to grow in Rameswaram and further south on the coast.

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Though oil sardines are abundant on the Tamil Nadu coast, for some reason, Tamils don’t fancy eating them – people in Kerala do. And, as if to mark the historical disjunct between Kanyakumari and rest of Tamil Nadu, people in that district consume oil sardines.

When the cold water of the ocean bottom rises up, it creates conducive temperatures as well as brings protein-rich food for these fishes, promoting breeding. But due to climate change the water remains warm near the surface and breeding is curtailed.

In 2017, Tamil Nadu’s overall fish landings dipped by 7% because oil sardine catch went down by more than 35%, notes a CMFRI report. In 2016, however, all-India oil sardine catch had gone down after 20 years but Tamil Nadu held its fort. The fall in 2017 has been attributed to many factors. CMFRI scientists say there is a strong link between the breeding of oil sardines and climate change phenomena. Oil sardines lay their eggs mainly between June and August. At that time, if there is rainfall of 20 to 30 mm every day then they breed normally. Researchers also talk about the effect of sun spots that occur once in 11 years. In recent times, El Nino too has had its effect, says V Kripa, a researcher at CMFRI. “Oil sardines breed more off the eastern coast rather than the western. In 2015 and 2016, their catch was down nationally. The reason was overfishing in 2012 which destroyed the hatchlings too. In 2015 and 2016, El Nino effect was pronounced,” she adds.

When the cold water of the ocean bottom rises up, it creates conducive temperatures as well as brings protein-rich food for these fishes, promoting breeding. But due to climate change the water remains warm near the surface and breeding is curtailed.

In 2017, TN’s loss was Kerala’s gain. The oil sardine catch in that state went up. T T Ajithkumar, a researcher at the Indian Council of Agricultural Research’s National Bureau of Fish Genetic Resources, says, “It is natural that fish migrate towards regions that offer a supportive breeding environment.”

Fishermen in Tamil Nadu say they don’t use the oil sardine nets as much as they used to. C Brittos, a fishermen at Uvari, says: “Folks at my village and neighbouring villages in Tirunelveli go for oil sardine fishing, not as much elsewhere in the state,” he adds. “If merchants from Kerala who buy these fish get oil sardines from Kerala fishermen then they don’t come here. So we are hesitant about concentrating on oil sardines,” says M Ganesan, a fisherman of Cuddalore.

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