As storms and rising temperatures make the Arabian Sea increasingly unpredictable, fishers along India’s southwest coast are expressing concern over the future of the oil sardine – a long-time staple of their livelihoods. Their latest worry: unusually small sardines landing in large numbers.
Jackson Pollayil, president of the Kerala Swatantra Matsyathozhilali Federation, an independent trade union for fish workers, recently warned that sardines in the state’s coastal waters have dramatically shrunk in size. On March 15, fishers were forced to sell sardines for as little as Rs 18 per kg – less than a tenth of their usual price.
However, this trend may simply reflect an abundance of young fish, according to scientists at the Central Marine Fisheries Research Institute. “Since June 2024, breeding and recruitment have been strong,” says Grinson George, the institute’s director, referring to the natural process in which juvenile fish mature into adults. He notes that favourable environmental conditions have led to a large influx of “0-year class” sardines – those spawned within the past year.
Sardines are an iconic species, referred to as kudumbam pularthi (the one that nourishes the family in Malayalam) in Kerala. They are an affordable staple food and a lifeline for local fishers. Fluctuations in sardine catch always make headlines.
Question of timing
While the concerns among Kerala’s fishers are genuine, fisheries experts suggest that the appearance of small sardines at this time of year is not unusual. “What we are seeing now are not fully grown fish,” explains KK Baiju, a fisheries expert at the Advanced Centre for Atmospheric Radar Research at the Cochin University of Science and Technology. The spawning period for oil sardines along Kerala’s coast typically occurs from June to August, influenced by monsoon rains and cooler temperatures. “The sardine season tends to peak later in the year, during the monsoon,” he tells Mongabay India.
Marine biologists note that young sardines typically grow to around 14 centimetres within six to seven months and enter their spawning cycle within another two to three months. “The continued and significant recruitment of oil sardines in 2024 has led to a steady availability of small-sized sardines during the last quarter of the year,” says Ganga U, principal scientist at the Finfish Fisheries Division of the central institute. She also speculates that competition for food may be impacting their growth, adding, “Studies on this are currently underway.”
Climate factor
While scientists point to healthy recruitment as a reason for optimism, many fishers remain unconvinced. Pollayil attributes the shrinking size of sardines to climate change, highlighting the warming coastal waters that may be depleting essential nutrients and hindering the development of juvenile fish. Charles George, leader of the Kerala Malsyathozhilali Aikyavedi trade union, shares this concern. “It’s clearly a case of climate change reducing the food available for fish, not overfishing, as is often reported.”
Fishers in Thiruvananthapuram recall a time when sardines were abundant, swarming near the surface in large, shimmering schools. “They would come bouncing, close to the surface,” says Davidson Anthony Adima, a fisherman in his early 40s. “We don’t see anything like that these days.” He blames warming ocean waters and overfishing by trawlers, which catch even small fish.
“Overfishing is definitely a concern. We don’t know much about sardines, though there are several site-specific studies,” says Rajeev Rajakrishnan, a deep-sea fisheries expert based in Kerala.
New studies and findings
While the impact of climate change on local sardine populations is still being studied, existing research suggests a shift in their distribution. A central marine fisheries institute study, titled The Enigmatic Indian Oil Sardine: An Insight, notes that since the late 1980s, sardines have expanded their range toward India’s east coast, likely in response to rising sea temperatures and increased fishing pressure in the southwest. “The increase in sea surface temperature caused by climate change along the southern peninsula could have driven the northward expansion of Indian oil sardines to cooler areas,” the study observes.
The paper also warns that warming waters, marine heatwaves, and extreme weather events could disrupt the delicate environmental balance that sardines rely on – affecting food availability, reproductive cycles, and survival rates.
“Such influences affect gonad maturation and the progeny that will result,” says Ganga. Gonad development influences the fecundity, or ability to produce a new generation. “Extreme weather events can also indirectly affect fisheries by reducing the number of fishing days, which applies to all targeted fisheries.”
In Thiruvananthapuram, fishers say rough seas have already taken a toll. “The sea is not the same anymore,” says Mariyannii Miyyalpillai, a fisherman in his 70s from the district’s southern coast. “It can be rough – not just during the monsoon, but at any time. We have to take more risks now. There is a lot of uncertainty.”
Cycle of decline and recovery
The question of whether oil sardine stocks are collapsing has sparked considerable debate. Some scientists warn that declining landings are a sign of trouble. “A sharp decline has been observed in the annual landing of the resource, and it is on the verge of collapsing due to climatic and anthropogenic perturbations,” a recent study notes.
However, central marine fisheries institute scientists reject this claim. “There has been no history of any oil sardine collapse on a pan-India basis,” Ganga points out. “Whenever populations have seriously declined, a combination of reduced fishing pressure and favourable environmental conditions has led to the fisheries bouncing back.”
Baiju explains that oil sardine populations fluctuate in cycles. “Every 10 years or so, there is a decline – a cyclical fluctuation, so to speak,” he says.
The species is highly sensitive to environmental changes, including shifts in sea temperatures, rainfall patterns, and competition from other species.
Though sardine stocks have declined in certain years, historical data suggests resilience. “While the failure of the Indian oil sardine fishery in certain years has caused much concern among all stakeholders, the resource has always recovered after a few years,” the study notes.
A return to form
Kerala’s sardine fishery has experienced sharp fluctuations in recent years. Catch volumes dropped to around 3,000 tonnes in 2021, before rebounding to nearly 1.4 lakh tonnes in 2023. Nationwide, oil sardine landings were estimated at 245,420 tonnes in 2023, with total fish landings reaching 3.55 million tonnes.
“The oil sardine landings during the 2024 fishing season, especially in the last quarter (October–December), were quite high, and it is likely that the landings will show a stable trend for 2024 as well,” Ganga assures.
Final estimates of 2024’s marine fish landings are still being processed using ICAR-CMFRI’s stratified, multistage random sampling design. However, scientists remain optimistic.
Despite fishers’ concerns, experts note that the high presence of juvenile sardines – often described as “small-sized” – signals a strong recruitment cycle. However, they caution that high catch rates alone do not guarantee long-term abundance. “Understanding the biology of the fish and how it is influenced by weather and climate events is crucial to its management and long-term sustainability,” Baiju says.
With studies ongoing along Kerala’s coast and beyond, fisheries scientists stress the need for a comprehensive approach. “We still need multi-site studies to assess the climatic, environmental, and human impacts on sardines,” says Rajakrishnan.
This article was first published on Mongabay.
