Mangroves ecosystem in India vulnerable to collapse due to cyclones, shrimp aquaculture, says report

The report said that Southeast Asia accounts for 49,500 sq km or 33.6 per cent of global mangrove cover with Indonesia alone having 21 per cent of the world’s mangroves.

At a mangrove patch near Khambhat in Gujarat. Photo by Bharat Jethva

Written by: Gopal Kateshiya

4 min readRajkotJul 27, 2024 10:26 AM IST First published on: Jul 27, 2024 at 10:26 AM IST

Large swathes of natural mangrove forests on the southern Indian coast are critically endangered while those on the west coast, including in Gujarat, are vulnerable to collapse due to human activities like development of shrimp aquaculture and natural threats such as tropical storms, a report released by Global Mangrove Alliance (GMA) on World Mangrove Day on Saturday, said.

Titled ‘The State of the World’s Mangroves, 2024’, the report assessed the world’s natural mangrove forests spread over 1.47 lakh sq km by using satellite data to plot a global map of mangroves with 2020 as the baseline.

The GMA report highlighted that mangroves in Lakshadweep archipelago and on the coast of Tamil Nadu are critically endangered, as they face rising sea levels due to global warming. The report also underlined that mangroves on the western seaboard – extending from Gujarat in the west to Kerala in the southern peninsular India – are vulnerable to collapse.

The report said that Southeast Asia accounts for 49,500 sq km or 33.6 per cent of global mangrove cover with Indonesia alone having 21 per cent of the world’s mangroves. It is followed by west and central Africa (22,802 sq km), north and central America and Caribbean (21,270 sq km), south America (19,469 sq km), Australia and New Zealand (10,348 sq km) and south Asia (in which India is located) with 9,749 sq km or 6.6 per cent of the world’s mangrove forests.

“Conversion to aquaculture, oil palm plantations and rice cultivation together explain 43 per cent of mangrove losses between 2000 and 2020. Natural retraction, influenced by climate change, sediment shifts and rise in sea level, also significantly impacted mangrove areas,” the report said, adding mangrove area of 4,083 sq km has been lost since 1996.

The report highlighted that shrimp aquaculture is a major driver behind the loss. “From the 1980s, what had been aptly termed a ‘slash and burn industry’ has wreaked havoc on both mangroves and the traditional coastal communities… Significant losses are still occurring in Kerala and eastern India, Indonesia, northeast Brazil and northwest Mexico, where the industry is still expanding.”

“Industrial shrimp farming, in particular, has spread especially fast into the mangrove areas of Asia, Africa, and Latin America with devastating results… Most shrimp farms are constructed within the vital intertidal zones, resulting in the total removal of mangroves,” the report added.

Incidentally, shrimp farming has emerged as a major commercial activity in states like Andhra Pradesh, West Bengal and Gujarat in recent years. In 2024-25 Union Budget, the government has announced incentives for shrimp farming and exports of shrimps.

As per the India State of Forest Report, 2021, mangrove cover in India is estimated to be spread across 4,992 sq km. With estimated 2,114 sq km of mangrove forests, West Bengal has the largest mangrove cover in India. Gujarat comes second with an estimated area of 1,177 sq km, with mangrove forests largely located in Gulf of Kutch and Gulf of Khambhat. With an estimated mangrove forests spread over 794 sq km, Kutch district has the largest mangrove area in Gujarat.

To augment mangrove cover in India, the Union government had launched the Mangrove Initiative for Shoreline Habitats & Tangible Incomes (MISHTI) programme last June to plant mangroves in 540 sq km on the coastline of 11 states and two Union territories. Last year, six major corporations had signed MoUs with the Gujarat forest department to plant mangroves in 30 sq km on the state’s coastline.

“One of the major drivers of degradation of mangroves on the coast of Gulf of Cambay (Khambhat) is severe grazing and lopping during the flowering season of mangroves. This not only damages the mangrove stock but also reduces the availability of propagules for their natural regeneration. Therefore, mere protection of mangroves could also ensure their growth and enhance ecosystem benefits multi-fold,” said Bhart Jethva, executive committee member of Mangrove Society of India and a well-known conservationist of Gujarat.

Experts said that mangroves, which grow in intertidal zones of sea coasts, act as breeding grounds for fish and crabs, natural barrier against cyclones, seashore erosion and salinity ingress, as well as sequester large amounts of carbon. The GMA report said that mangroves store an average of 394 tonne of carbon per hectare. The GMA has set a target of doubling protection by 2030 and reducing mangrove losses due to human activities to zero.