Exploring Values and Beliefs in a Complex Coastal Social-Ecological System: A Case of Small-Scale Fishery and Dried Fish Production in Sagar Island, Indian Sundarbans

The survivability of the small-scale fishery and dried fish production in Indian Sundarbans, despite increasing threats posed by climate, environmental, economic, and policy drivers, suggests that they possess certain unique strengths and capabilities. One thread of these strengths is connected to the fact that Sundarbans’ fishery system is strongly anchored in the values and beliefs of the local fishing communities. There is, however, limited empirical information available on the prevailing individual and collective attitudes, expectations, traditions, customs, and, above all, values and beliefs that strongly influence local fishing communities of Sundarbans. This manuscript aims to address this gap by drawing on qualitative data to (1) map the nature of values and beliefs associated with the Sundarbans’ Sagar Island fishing communities who are engaged in small-scale fishery and dried fish production; and (2) highlight the contributions of values and beliefs to the small-scale fishery and dried fish production systems of Sagar Island. Our study reveals that historical factors such as the patriarchal and patrilineal system prevalent in the Indian Sundarbans as well as the current drivers, including environmental and social-economic changes, create inconsistent values and beliefs among male and female members of its society. Issues around values and beliefs are heavily influenced by social-ecological realities comprising material, relational and subjective dimensions. They can range from being strictly personal to largely community-oriented as they are shaped by realities of gender, class, power dynamics, and politics. Values and beliefs are fundamental to human perception and cognition but often get neglected in mainstream literature covering human dimensions of resource management. Our research adds weight to the theoretical and place-based understanding of the contributions of values and beliefs to the small-scale fishery and dried fish production systems. We learn from the case study that values and beliefs can act as mirrors, reflecting the current as well as future realities of small-scale fisheries and dried fish production systems and provide important directions for sustainability and viability of the entire social-ecological system that hosts this sector.

Assessment and Attribution of Mangrove Forest Changes in the Indian Sundarbans from 2000 to 2020

The Indian Sundarbans, together with Bangladesh, comprise the largest mangrove forest in the world. Reclamation of the mangroves in this region ceased in the 1930s. However, they are still subject to adverse environmental influences, such as sediment starvation due to migration of the main river channels in the Ganges–Brahmaputra delta over the last few centuries, cyclone landfall, wave action from the Bay of Bengal—changing hydrology due to upstream water diversion—and the pervasive effects of relative sea-level rise. This study builds on earlier work to assess changes from 2000 to 2020 in mangrove extent, genus composition, and mangrove ‘health’ indicators, using various vegetation indices derived from Landsat and MODIS satellite imagery by performing maximum likelihood supervised classification. We show that about 110 km2 of mangroves disappeared within the reserve forest due to erosion, and 81 km2 were gained within the inhabited part of Sundarbans Biosphere Reserve (SBR) through plantation and regeneration. The gains are all outside the contiguous mangroves. However, they partially compensate for the losses of the contiguous mangroves in terms of carbon. Genus composition, analyzed by amalgamating data from published literature and ground-truthing surveys, shows change towards more salt-tolerant genus accompanied by a reduction in the prevalence of freshwater-loving Heiritiera, Nypa, and Sonneratia assemblages. Health indicators, such as the enhanced vegetation index (EVI) and normalized differential vegetation index (NDVI), show a monotonic trend of deterioration over the last two decades, which is more pronounced in the sea-facing parts of the mangrove forests. An increase in salinity, a temperature rise, and rainfall reduction in the pre-monsoon and the post-monsoon periods appear to have led to such degradation. Collectively, these results show a decline in mangrove area and health, which poses an existential threat to the Indian Sundarbans in the long term, especially under scenarios of climate change and sea-level rise. Given its unique values, the policy process should acknowledge and address these threats.

PHYTOREMEDIATION OF HEAVY METALS BY THE DOMINANT MANGROVE ASSOCIATE SPECIES OF INDIAN SUNDARBANS

The present study aims to investigate the phytoremediation potential of zinc (Zn), copper (Cu), and lead (Pb) by two dominant mangrove associate species, Suaeda maritima, and Salicornia brachiata, found in the high saline supralittoral zone of Indian Sundarbans in four stations of the Hooghly-Matla estuarine complex during the premonsoon season (May 2019). We found that concentrations of biologically available heavy metals (HMs) in the ambient soil and bioaccumulated HMs within the vegetative plant parts occurred as per the order: Sagar South > Bakkhali > Jharkhali > Bali Island. The order of biologically available and bioaccumulated HMs was Zn > Cu > Pb. Interestingly, the selected HMs display high organ-specificity for both species with the highest enrichment in roots, followed by stems and leaves. We propose that these halophytes could be used as agents of phytoremediation and their farming would be effective in the ecorestoration of this deltaic complex in context to conservative pollutants.

Trend analysis of weather parameters over Indian Sundarbans

Sundarbans in West Bengal of India by virtue of its strategic location in the Eastern coast on the Bay of Bengal falls in one of the most vulnerable zones of abrupt climate change. Temporal trends of weather parameters of Canning Town (22o18'10.8'' N Latitude, 88o39'58.4'' E Longitude, elevation 3.52 m msl) representing Indian Sundarbans were analysed by non-parametric Mann-Kendall test and Sen's slope approaches. Analysis of long term rainfall data (1966-2015) indicated that Canning receives a mean annual rainfall of 1821 mm (±341.8 mm) with a considerable variation (CV = 18.8%). The results revealed that total annual rainfall trend decreased non-signicantly at the rate of 0.94 mm yr-1. On an average 84.4 rainy days in a year was recorded in the region, whereas during last ten years (2006-2015), the number of rainy days was reduced to 79.7 days yr-1. There was no signicant change in maximum, minimum and mean temperature of the region. Bright sunshine hours declined signicantly at an annual rate of 0.055 hr yr-1. Reference crop evapotranspiration (ET ) calculated using FAO Penman-Monteith method revealed that annual ET signicantly decreased at the rate of 5.98 mm yr-1. There was 2.7 times surplus rainfall than crop evapotranspiration during monsoon months indicating very high scope of water harvesting to tackle water logging during the monsoon season and unavailability of fresh water for irrigation during lean season.

COMPARATIVE STUDY OF HEAVY METALS IN THE MUSCLE OF TWO EDIBLE FINFISH SPECIES IN AND AROUND INDIAN SUNDARBANS

We analyzed the concentrations of zinc, copper, and lead in the muscle of two commercially important finfish species namely, Pampus argenteus and Scatophagus argus in and around the World Heritage site of Indian Sundarbans from 8th to 15th July 2021 using an Atomic Absorption Spectrophotometer. The sequence of bioaccumulation of the selected metals is as per the order Zn > Cu > Pb irrespective of the species. The degree of metal accumulation showed variation between the species with the highest value in Scatophagus argus followed by Pampus argenteus, which may be related to the difference in their food habit or degree of exposure to ambient media contaminated with heavy metals.

New records of cheilostome Bryozoa from the eastern coast of India encrusting on the exoskeleton of live horseshoe crabs of Indian Sundarbans

Bryozoans are common commensal on hard surfaces and cover slow-moving animals like molluscans, sea turtles, brachyuran crabs, and horseshoe crabs. A total of six species of bryozoans belonging to four genus under three families of order Cheilostomatida were recorded encrusting on the carapaces of horseshoe crabs collected from Indian Sundarbans along the east coast of India and two among them, viz., Biflustra savartii (Audouin, 1826) and Sinoflustra arabianensis (Menon & Nair, 1975) are reported for the first time. Additionally, Jellyella tuberculata (Bosc, 1802) is reported for the first time from West Bengal coastal waters, previously known only from the Odisha coast of India. Both male and female horseshoe crabs were found to have been encrusted with bryozoan mats, although adequately not known about the life stages of their encrustation.