Is sardine phasing out? Effects of climate change on marine ecosystem, blue economy in Kerala

The signs of the climate crisis are real and emphatic, whether it's the melting of the ice in the Arctic, the record rise in global temperature or the unseasonal torrential rain in various parts of the globe. Kerala, the land of backwaters and greenery, too has been feeling the brunt of the climatic changes.
While the extreme temperatures and heatwave conditions brought us closer to this fact, the story of the marine ecosystem in the region is no different. Prof A Bijukumar, Head, Department of Aquatic Biology and Fisheries, in a chat with Onmanorama, analyses the effects of climate change on Kerala and its economic implications on marine livestock.

Though the local oceanic phenomena need not always have a connection with climate change, it is tough to analyse one-off unprecedented events. They can be properly assessed only when they are repeated or happen elsewhere, says Bijukumar. Occurrences like the receding sea along a small stretch of Alappuzha beach recently and the swell waves there days later could have been triggered by neap tides. They are rare, but not unusual. The National Centre for Earth Science Studies (NCESS) conducts studies on such developments regularly. Nevertheless, there is an overall change in the water balance in the marine system. It is in the arctic region where the change is mostly evident and the effects reverberate on other parts of the globe, he says.

Huge change in the overall oceanic temperature
The Arabian Sea was a region identified with comparatively low temperature. But due to the impact of climate change, there has been an increase in the temperature above average. That leads to an increase in the presence of water vapour in the atmosphere which ultimately results in the rise in humidity and the number of low-pressure areas in the sea. The presence of hot winds has also been increasingly observed in the region.

Local fisheries and the marine economy affected
Climate change has left a huge dent in the fisheries sector. Some years ago, Kerala was numero uno in the production of sardines (mathi). The state cannot claim the status any more now, as there has been a 35 per cent decline in the availability of that fish species here. The increase in temperature diminishes the capacity of the seawater to carry oxygen, increasing the number of Oxygen Minimum Zones (OMZs). This low oxygen saturation in seawater drives fish to migrate to other regions rich in oxygen. For example, earlier, sardine fishing nets were absent in Andhra Pradesh. Now there is a large-scale use of the fishing nets for this variety of fish as its population in this region has soared.
It's estimated that sardines worth about 2500 crore is caught every year in India. However, the drought in the fish species from 2013 to 2021 has incurred a loss of Rs 10,000 crore to the fisheries sector. Though it registered a comeback in 2022 with a catch of 1.01 lakh ton, they were smaller in size, according to the fisheries department.

Other varieties
Changes have also been noted in the population of fish like tuna (choora) which are migratory. Studies have shown a change in the breeding pattern of fish like red snapper fish (navara) as well.
How these changes will affect the future of such species depends on how we manage the situation. In India, there is regulation on trawling small fish only in Kerala. The government has issued order prohibiting the trawling of 59 varieties of small fish when their numbers dwindle.
Most of the time it doesn't take effect because of the dearth of a proper surveillance system. So, when the bigger fish varieties face a dip, fisher folks go for smaller ones causing an overall decline in their count. So, we need a proper system of sustainable fishing practices in place. Otherwise, the common fish varieties will disappear soon from Kerala coast as in the case of catfish (Thed), Trevally (Parava) and so on. Indian Halibut (Ayirampalli) was yet another fish, which was common in Kerala but is hardly seen on the Kerala coast these days.

Newcomers
Meanwhile, in Kerala, some new species are now abundant. For instance, the presence of triggerfish (Klathy) has increased considerably across the state. It may adversely affect the fishermen as they are very cheap now. However, they seem to be slowly gaining domestic as well as export markets.
The solution
We have taken steps for sustainability like changing to solar power, e-vehicles and so on. But, where we lack is in adapting to changing circumstances. When a resource is exhausted vis-a-vis climate change, there should be a system that helps us make use of new or available resources. For instance, we were cultivating crops, which need large amounts of water but when there is a shortage, we must start using seed varieties that are capable of resisting dry conditions. Turning to farming techniques tolerant to water salinity is yet another example. Similarly, fishermen should take recourse to alternative resources when there is a depletion of conventional marine livestock. Adaptability is the need of the hour for a better future.