Rise in jellyfish numbers, coral bleaching among impacts on India’s coastline
The Union ministry of earth sciences (MoES) has informed the Lok Sabha that there is a substantial increase in the population of jellyfish due to increasing sea temperature in the Arabian Sea. The proliferation of jellyfish has also resulted in the overfeeding of sardine larvae, leading to a considerable reduction in sardine fishery.
The MoES, on information from Centre for Marine Fisheries Research Institute (CMFRI), also said on Friday that frequent coral bleaching events occurred at Gulf of Mannar and Andaman and Nicobar Islands which are mostly coinciding with El Nino events indicative of increase in sea surface temperature. El Niño and the Southern Oscillation (ENSO) is a periodic fluctuation in sea surface temperature and the air pressure of the overlying atmosphere across the equatorial Pacific Ocean according to the National Oceanic and Atmospheric Administration (NOAA).
ENSO has a major influence on weather and climate patterns such as heavy rains, floods and drought. El Niño has a warming influence on global temperatures, while La Niña has the opposite effect.
During 2021-2026, MoES will continue its study of marine living resources including physical processes, bio-geochemistry and biological response to varying ecosystem processes in Arabian Sea and bio-inventorisation of various marine species, the reply added.
The fishing community has also been impacted by these changes in the past five years. “Fishermen along Arabian Sea have been impacted by a massive increase in jellyfish numbers. In fact, they have created a business opportunity out of it. In some ports like Okha and Jakhau in Kutch, fishermen have started processing jellyfish and exporting to China where its eaten. They sell it to exporters for Rs5 per kg. Fishermen have also been noticing a big fall in the catch of pomfret and some prawn varieties. Their reduction is very worrying and we are not sure what is the reason,” said Bharat Patel, general secretary of Machchimar Adhikar Sangharsh Sangathan, which represents the fishing community in Gujarat.
According to a paper led by Indian National Centre for Ocean Information Services published in Springer’s Ecological Processes journal, oceanic warming often result in higher jellyfish densities. Rising temperatures in global seas may trigger the success of some jellyfish species and change species distributions. It also states that jellyfish swarms and beach strandings have increased which has led to adverse impacts on aquatic ecology and human enterprises like clogging of fishing nets and disruption of tourism.
In reply to another question on climate change impacts in India raised in Lok Sabha, MoES has said, “Extreme climatic events or disaster weather events have increased significantly across India during the 21st century. An increase in various extreme weather and climate events such as heavy rainfall, floods, droughts, cyclones, heat waves and cold waves have been observed in the country in line with the increase in the extreme events observed over various parts of the globe.”
Based on the available climate records with MoES, surface air temperature over India has risen by about 0.7 degree C during 1901–2018 period which is also accompanied by an increase in moisture content. The sea surface temperatures in the tropical Indian Ocean have also increased by about 1 degree C during 1951–2015.
Rajasthan, Andhra Pradesh and Delhi are among states reporting increased number of heat waves and Haryana, J&K and Uttar Pradesh have reported increase in number of cold waves during the recent years, according to MoES.
Future projections based on modelling of various climate change scenarios indicate significant changes in the mean and extremes of several key climatic parameters over the Indian subcontinent and the adjoining areas like land temperature, monsoon, Indian Ocean temperature and sea level, tropical cyclones and the Himalayan cryosphere.
Among other measures, India Meteorological Department (IMD) in collaboration with local health departments has started heat wave warnings. National Disaster Management Authority and IMD are working with 23 states prone to high temperatures and heat waves to develop heat action plans.