KOCHI: While the strengthening of El Nino has caused concerns about monsoon failure in India, the Central Marine Research Institute (CMFRI), has issued an advisory to fishermen to brace for the situation. El Nino will adversely affect the recruitment of small pelagic species, especially oil sardine, which can reduce the overall marine fish production in 2027, said CMFRI director Grinson George.
“Though El Nino is a climate phenomenon characterised by the unusual warming of the surface water in the central and eastern equatorial Pacific, it influences the Indian Ocean through shifting wind patterns and oceanic currents. There is an atmospheric bridging mechanism called Walker circulation that transfers heat from the Pacific Ocean to the Indian Ocean,” he explained.
“There will be a lag of four to six months for the heat transfer. As per the forecast, El Nino is expected to peak by November-December period and the impact will be visible by April-May 2027,” Grinson added.
Though there were concerns about the climate driven stunting of oil sardine, the stocks are abundant this year and the fishermen are getting good catch of the normal size sardine, Grinson told TNIE.
“The small pelagic fish resources, including oil sardine, are expected to shrink in 2027 due to the impact of El Nino. Sardine is a zero year fishery resource, which enters the fishery cycle during the same year of recruitment. So the survival of individual sardine is important to ensure further recruitment,” he said.
“The physiological activities of the oil sardine will start in May and it will start laying eggs during May-June period. This new recruits will enter the fishery in four months. The maturing of the egg to larvae will be hindered due to the warming of the surface water caused by El Nino,” he added.
Though other pelagic species will also be affected by the warming of the surface water, there is no other species that are climate sensitive like oil sardine. The reduction in recruitment of oil sardine may affect overall fish production.
“We are trying to sensitise fishermen against juvenile sardine to avoid depletion of resources. There will not be any big difference in overall catch as other species will try to occupy the space of oil sardine. Oil sardine is a resilient species that can bounce back even if the recruitment is affected due to El Nino, said Grinson.
Addressing a scientist-farmer interface programme on the occasion of the National Fish Farmers Day at CMFRI on Friday, he said, “Established information indicates probability of marine heatwaves, increased sea surface temperature and high salinity during April and May in 2027. Sustained warming could adversely affect coral reefs, resulting in coral bleaching and reducing the natural abundance of reef-associated species such as red snapper”.
Urging fish farmers to brace for the situation, Grinson said sudden rainfall following prolonged periods of high temperature and salinity could also trigger rapid salinity fluctuations, disrupting coastal aquaculture activities.
He stressed the need for continuous monitoring of ocean conditions and adaptive management to minimise the impact of climate-driven changes on marine resources.