Coastal Bangladesh Research Articles

Length-weight relationships and Fulton’s condition factors of two flatfishes, Cynoglossus cynoglossus and Cynoglossus lingua, from Cox’s Bazar coast, Bay of Bengal

Abstract Length-weight relationships (LWRs) and Fulton’s condition factor were estimated for two flatfishes, Cynoglossus lingua Hamilton, and Cynoglossus cynoglossus (Hamilton), from the Cox’s Bazar coast of Bangladesh. Sampling was done from September to November 2022 from the landing center of Bangladesh Fisheries Development Corporation. In this study, the maximum total length of C. cynoglossus (34.0 cm) is a new record for this species. The length-weight relationships for these two species were highly significant (P < 0.001) with adjusted r2 values of 0.918 and 0.927 for C. lingua and C. cynoglossus, respectively. The calculated growth coefficient (b) for C. lingua and C. cynoglossus was 2.873 and 3.359, respectively. The estimated Fulton’s condition factor (Kn) was 0.42 ± 0.05 for C. lingua and 0.72 ± 0.11 for C. cynoglossus. No information about the population parameters of C. lingua from the Bay of Bengal has been reported previously in any scientific database. The maximum Kn value of C. lingua was observed in the 13.0–15.9 cm length class while that of C. cynoglossus was found in the 31.0–33.9 cm length class. Our estimated LWR and Fulton’s condition factor values for these two flatfishes can be useful for management and conservation.

Women as subjects of risk in Bangladesh’s coastal riskscapes

In this article, I examine the assumptions underlying the idea of women as vulnerable and at risk, and how this understanding contributes to shaping practices of climate change adaptation. The article is based on ethnographic fieldwork in the expert community in Dhaka and in a climate change adaptation field site in coastal Bangladesh. Following Ananya Roy’s work, I understand coastal Bangladesh to be a riskscape, a geographical space suffused with imaginations of anticipated risks that must be managed through disaster risk reduction and climate change adaptation. Roy further argues that riskscapes create new subjects of risk, and that such subjects are highly gendered because development has tended to focus on poor women ‘in very specific ways’. In this article, I build on Roy’s insights to explore how women are constructed as ‘subjects of risk’ in climate change adaptation. I also show how climate change adaptation, in becoming the new buzzword for development, continues to focus on poor women in very specific ways, which are applied to fit with the climate change ‘metacode’. While well-intended, the understanding of women as subjects of risk is imbued with ambivalence, because it may contribute to supporting structures that make women vulnerable by normalizing relations of risk.

Farmers’ perceptions, determinants of adoption, and impact on food security: case of climate change adaptation measures in coastal Bangladesh

ABSTRACT Coastal households in Bangladesh are exposed to a variety of extreme climate events, which represent a major threat to food security. However, there is a dearth of empirical research on the adoption and impact of climate change (CC) adaptation measures on food security. Using cross-sectional data from 750 households, this study investigates farmers’ perceptions of CC, the drivers of adaptation measures, and the impact on the household food security in coastal areas of Bangladesh. The data were analyzed using descriptive statistics, multivariate probit, and propensity score matching. According to the findings, most respondents believed that CC is occurring. Climate change adaptation measures were classified into six categories. Borrowing and selling of assets, as well as off-farm labour employment, were used as adaptation measures by more than 85% of the households. Crop farming-related adaptation measure was used by around 47% of the households. Among the explanatory factors, cultivable land area, farming experience, access to climate information, yearly income, and location of households had a significant role in the choice to use adaptation measures. The findings suggested that agriculture-based adaptation measures, such as a change in crop farming technique, significantly reduced food insecurity, whereas off-farm labour employment, as well as borrowing and selling of assets, increased it (as measured on the household food insecurity access scale [HFIAS]). This analysis suggests that government and non-governmental organizations operating in coastal communities may want to prioritize actions to increase understanding and access to climate information amongst farmers and other households. Policies that are location-specific and specific to farmers’ needs must also be developed to fully reap the benefits of adaptation measures.

Toxic Residues in Fluid Commons: More-Than-Economic Dispossession and Shipbreaking in Coastal Bangladesh

ABSTRACT This article examines processes of ‘more-than-economic dispossession’ arising from pollution in the interconnected forests, tides, canals, rivers and humid airs – the fluid commons – of the shipbreaking region Sitakunda. It ethnographically explores how minority Zele fishermen and shipbreaking workers are experiencing three interrelated forms of ‘more-than-economic’ dispossession. First, extra-economic means of accumulating profits by dismantling ships in cheaper countries enables dispossession by pollution in coastal ecologies. Second, more-than-economic points to the structures of political power inequalities making marginalised Bangladeshis exposed to toxics in ways that cannot be economically compensated. Lastly, more-than-economic draws on ‘more-than-human’ ethnographies: affective experiences of sensing, tasting, hearing and smelling pollution reveal how toxic residues biophysically damage the health of both human and more-than-human, resulting in the loss of ability to ‘sustain life’. It thus joins the growing body of anthropological scholarship that expands on pollution as ‘matter out of place’ by taking its materiality seriously.

Early sowing increases nitrogen use efficiency of sunflower in wet clay soils

AbstractEarly sowing increases yield potential of sunflower on wet, saline clay soils but the effects on nitrogen (N) requirements have not been determined. In a 2‐year study on a drainable field with wet, saline clay soils in southwestern coastal Bangladesh, we investigated nitrogen use efficiency (NUE) and yield responses to N rates (0, 60, 90, 120, 150, 180 and 210 kg ha−1) for zero‐till sunflower cv. Hysun‐33 sown from November 30 (early) to December 30 (late). Early sowing produced highest seed yield (3.59 ton ha−1) and oil yield (1400 kg ha−1) at 150 kg N ha−1. Delayed sowing (December 15–December 30) reduced seed and oil yields by 4%–15% and 7%–18%, respectively. In late sowing, crops suffered from multiple stresses (soil–water deficit, salinity, and heat), which decreased yields. The N fertilizer requirement in late sowing was higher (180 kg ha−1) to achieve maximum yield, yet the yield was lower than from earlier sowing. Compared with nil N supply, the rates of 60–150 kg N ha−1 increased seed and oil yields of the early‐sown sunflower by 1.3–3.3 times and 1.2–2.9 times, respectively, whereas the rates of 180–210 kg N ha−1 decreased seed and oil yields by 2%–5% and 7%–14%, respectively. Higher net profit (US$764) was also achieved from earlier sowing with 150 kg N ha−1. We conclude that under wet and saline clay soils, higher sunflower yield in early sowing is attributable to lower stress that increased NUE and decreased N requirement.

Tropical cyclone data calibration for the estimation of a path of a cyclone along the coast of Bangladesh

Tropical cyclone data calibration for the estimation of a path of a cyclone along the coast of Bangladesh

Exploring the Experience and Well-being of Female Evacuees in Coastal Bangladesh through a Phenomenological Lens

Introduction:Women in coastal Bangladesh face greater challenges while staying at evacuation centers during cyclone emergencies. This study explores the lived experience of women and their well-being as evacuees.Method:The research undertook a phenomenological approach to conduct in-depth interviews of nineteen women from three extremely vulnerable districts of coastal Bangladesh.Results:The interviews revealed that women experienced obstacles to maintaining hygiene, using the toilets and accessing privacy, and suffered distress as pregnant women, lactating mothers, and through menstruation, which affected them physically and hampered their mental health. Coming from a male-dominated socio-cultural background, female evacuees unaccompanied by male guardians experienced fear and uncertainty. Some participants recollected facing social pressure and overwhelming emotions as carers of children and elderlies, whereas some reconciled traumatizing incidents such as witnessing death. Such experiences led to anxiety, stress, and depression with either temporary or permanent trauma. Participants frequently mentioned panic attacks and stress-related physical issues such as heart palpitations, dizziness and light-headedness. However, spiritual beliefs and social bonds within the community enabled peace and optimism among the women. Findings highlight that certain factors determined women evacuees' experience of wellbeing. Social context of the women imposed burdens of responsibility and caused inaccessibility of resources to restore physical-mental wellbeing. The settings, infrastructures and environment of the evacuation centers were not women-friendly, which resulted in many negative experiences among the evacuees, greatly affecting their sense of wellness. However, participants could channel positive mindsets through prayers and spiritual faith. Women were able to access some resources and use these for their well-being through social bonding and connecting with the women within the shelters.Conclusion:Unconditional trust in a deity and sisterhood within communities have been two quintessential features of women, which played major roles in women’s experiences and molded their understandings of well-being in the cyclone shelters.

Post-cyclonic migration in coastal areas: An assessment of who, where, why migrates, and barriers to migration

As cyclones increase in frequency and severity, more people experience their adverse impacts. However, little is known about post-cyclonic migration patterns in coastal southern Bangladesh, a cyclone-prone area. This paper compares post-cyclonic migration patterns with non-cyclonic migration in terms of who migrates, where they migrate to, why they migrate, and the barriers to migration. 472 households across 16 blocks (moujas) were selected by stratified sampling. A survey collected individual and household-level information regarding demographics, socioeconomy, and migration patterns in non-cyclonic and post-cyclonic situations. The analysis demonstrated that, in non-cyclonic situations, secure employment represented the migrants’ main livelihood while, following a cyclone, non-secure professions such as day-labouring were the most prevalent. The post-cyclonic migrants were, overall, less educated and less wealthy landless and marginal farm holders compared to those who migrated in the non-cyclonic period. Most people migrated to nearby districts following a cyclone, whereas long-distance migrations were found in non-cyclonic periods. We thus argue that, in a non-cyclonic period, people migrate for employment and are in a stronger position, socioeconomically, than post-cyclonic migrants, while, in a post-cyclonic period, it is mainly socioeconomically distressed people with non-secured day-labouring jobs who migrate a short distance area.

Estimating Stock Status and Biological Reference Points of the Sardine Fishery Using the Surplus Production Model from the Bay of Bengal, Bangladesh

This research examined the biological reference points (BRPs) and stock status of the sardine fishery in the Bay of Bengal (BoB), Bangladesh, to determine the sustainability of this resource. The Monte Carlo method (CMSY), the Bayesian state-space Schaefer surplus production model (BSM), and the ASPIC (a Stock Production Model Incorporating Covariates) software suite, were used to analyze catch–effort data obtained from the Yearbook of Fisheries Statistics of Bangladesh. All models derived maximum sustainable yields (MSY) ranging from 37,900 to 41,280 t, which is quite near to the catch from the latest year (38,051 t in 2020), indicating the fully exploited status of sardines. The estimated B < BMSY and F > FMSY values from the BSM and Schaefer models indicate a poor biomass and an unsafe fishing status. For Schaefer and BSM, the calculated F/FMSY values were 1.07 and 1.06, and the B/BMSY values were 0.92 and 0.75, which also indicate the overexploited status of the sardine fishery in the BoB, Bangladesh. This information will aid in developing management strategies and conservation policies for the sustainability and rebuilding of this commercially important resource in the BoB on the Bangladesh coast.

Climate refugees or labour migrants? Climate reductive translations of women’s migration from coastal Bangladesh

ABSTRACT Climate reductive translations of migration attract international attention, but result in three problematic misreadings of Bangladesh’s socioecological landscape. First, attributing migration to climate change misreads coastal vulnerabilities and the importance of migration as a gendered livelihood strategy to deal with rural precarity and debt- both in the past and present. Second, misreading migration caused by brackish tiger-prawn cultivation, infrastructure-related waterlogging and riverbank erosion as ‘climate-induced’ hinders a discussion of long-term solutions for rural underemployment, salinisation, siltation and land loss. Lastly, framing climate change as causing ‘gendered displacement’ ignores the importance of affective kinship relations in shaping single women’s migration choices.

Microplastics and mesoplastics in surface water, beach sediment, and crude salt from the northern Bay of Bengal, Bangladesh coast

Microplastics and mesoplastics in surface water, beach sediment, and crude salt from the northern Bay of Bengal, Bangladesh coast

Assessing the Impact of Extensive Severe Cyclonic Storm Fani on the Coastal Communities of Bangladesh: A Case Study

This research article presents a numerical simulation of the extensive severe cyclonic storm Fani and its impact along the coast of Bangladesh, which made landfall in the coastal region of Odisha, India, on May 3, 2019. A semi-implicit finite difference method in Cartesian coordinates was employed in this study to solve vertically integrated shallow water equations. The approach allowed for effective forecasting of the storm Fani's impact on the region of choice. Our considered physical domain is discretized with high-resolution gird to cover all the big and small offshore islands. The model predicted water levels for a total of sixteen coastal stations of the Bay of Bengal along the coast of Bangladesh (from 2 May to 03 May 2019, at 3-h interval). Simulated water levels are found closely co-related to the reported data. The simulation results demonstrate that the semi-implicit finite difference method is an effective tool for simulating the storm surge and flooding caused by any severe cyclonic storm. The study also shows that the storm surge and flooding caused by Fani were significant, with a maximum surge height of over 5 meters in some areas. The simulated results provide insights into the spatial and temporal evolution of the storm surge and flooding, which can be useful for designing and implementing appropriate disaster management strategies in the affected regions. Overall, this research article contributes to the scientific understanding of the behavior of severe cyclonic storms and the associated storm surge and flooding, and provides a valuable tool for policymakers and stakeholders to develop and implement effective disaster management strategies in cyclone vulnerable coastal regions.

Growth performance and survival of oyster, Saccostrea cucullata (Born, 1778) and green mussel, Perna viridis (Linnaeus, 1758) cultivated in Bangladesh Coast

Oyster and mussel farming along the coasts and the desire to increase fishing revenue have created a boom in these types of farms. An experiment on culture of edible oyster (Saccostrea cucullata) and green mussel (Perna viridis) was performed at Gangamoti estuary in Kuakata, Bay of Bengal coast of Bangladesh from December 2021 to March 2022 to find out the appropriate culture method of the oyster, S. cucullata and green mussel, P. viridis. Initially, the average shell heights of S. cucullata and P. viridis were 8.8±1.62 and 6.9±1.89 cm, respectively; where average weights were153.4±13.23 and 84.78±11.78 g, respectively. After the culture period, oysters shell height and weight grew up to 9.1±1.98 cm and 163.2±12.54 g, respectively in rectangular basket and 8.9±1.45 cm and 157.2±11.31 g, respectively in velon screen bag. In case of oysters, the rectangular basket and velon screen bag displayed the minor progress in specific growth rate, 0.09±0.01 and 0.07±0.03, respectively. But green mussels did not show any growth rate. Oysters cultured in rectangular basket showed total mortality at day-90 and velon screen bag at day-75. Green mussels showed 100% mortality within 21 days of culture. Our experiment was the first attempt to culture these two mollusks in the Kuakata coast of Bangladesh. However, further intensive researches would be required to evaluate the culture feasibility of these two mollusks’ species in the Kuakata coast of Bangladesh.

Common sources and needs of weather information for rice disease forecasting and management in coastal Bangladesh

Rice farmers in coastal Bangladesh are severely affected by climate change. Climate variability and change impact crop production in numerous ways, including by changing occurrences of different rice diseases. Weather and climate information services (WCIS) can assist farmers in improving agricultural decision-making, in relation to rice disease management. Currently, however, farmers in coastal Bangladesh have limited access to accurate, timely, and location-specific information on weather and climate. To design actionable information services, it is important to know the types of information that farmers need. With this in mind, the current research addressed three questions: (i) What types of weather information do coastal farmers need to forecast rice diseases? (ii) What types of weather information are currently available to coastal farmers? (iii) How does weather information play a role in rice disease management-related decision-making? Results indicate that coastal rice farmers have access to weather and climate information services mainly through personal experiences, neighbouring farmers, agricultural extension agents, local knowledge and input dealers. During interviews, farmers indicated that they mainly needed information on temperatures, rainfall, relative humidity, cloud cover, fog and wind information to predict rice disease outbreaks sufficiently in advance. Raising awareness about application of climate information services in rice disease management and building the capacity of farmers through training and education is vital to address major challenges faced by the coastal farmers in accessing weather information. We conclude that the farmers need more accurate, timely, location-specific, trustworthy and actionable weather information services to forecast and manage rice diseases.

Groundwater quality assessment and health issues in coastal zone of Bangladesh

The purpose of this study was to assess the water quality index (WQI), heavy metal evaluation index (HEI), heavy metal pollution index (HPI) and hazard index (HI), and the associated environmental/human health issues of the south-western coastal Bangladesh (SWCB). Rajoir, Gangarampur and Ganapatipur villages were purposively selected from shoreline (X), interim (Y) and inland (Z) coast of SWCB. 40 ground water samples were collected from 20 sampling sites; and 18 variables, such as, temperature, pH, electrical conductivity (EC), dissolved solids (TDS), suspended solids, dissolve oxygen, total hardness, Cl, K, Ca, Cr, Mn, Fe, Ni, Cu, Zn, Cd and Pb ions were tested to perform the study. In addition, four focus group discussions were also conducted to understand the current health scenarios. The strong positive correlation between EC:Cu (r = 0.856), TDS:Mn (r = 0.664), TDS:Cu (r = 0.880), K:Mn (0.736) and Mn:Cu (r = 0.601) suggested the homogeneous sources of origin or/and anthropogenic activities or pollutant movement of these variables. The changing patterns of mean WQI, HEI, HPI, HIinfant, HIchild and HIadult of the study area were X(79.19)<Y(91.54)<Z(102.31); X(4.96)>Y(4.93)>Z(3.79); X(78.66)<Y(91.72)<Z(102.11); X(0.8)<Y(1.11)<Z(1.32); X(1.77)<Y(2.46) <Z(2.93); X(1.15)<Y(1.60)<Z(1.91), respectively. Therefore, it is argued that 66.67, 50 and 50% water samples from X, Y and Z coast grouped into category ‘very poor’, ‘excellent’ and ‘unfit’ based on WQI. In addition, 50, 40 and 50% water samples from X, Y and Z coast grouped into category ‘slightly affected’, ‘seriously affected’ and ‘moderately affected’ depending upon HEI. 100, 70 and 50% water samples from these villages were within the HPI (<100). Finally, the degree of pollution was increased from shoreline to inland areas based on HI results for infant, child and adult, respectively. Lastly, it confirmed that human health should be deteriorated for the long-term consumption of polluted/contaminated water and negatively impacted on biodiversity loss of the study area.

Correction: Islam, M.A.; Sato, T. Influence of Terrestrial Precipitation on the Variability of Extreme Sea Levels along the Coast of Bangladesh. Water 2021, 13, 2915

In the original publication [...]

Assessing effectiveness of nature-based solution with big earth data: 60 years mangrove plantation program in Bangladesh coast

BackgroundIn the climate change context, nature-based solution (NBS) is considered one of the effective tools to increase the resilience of socio-ecological system. The concept coincides with the government’s attempts of afforestation and reforestation programs that have been going on for 60 years in Bangladesh. This study, therefore, envisaged understanding how NBS (mangrove afforestation and reforestation) works to promote climate change resilience through the synthetization of remote sensing-based big earth data, statistical tools, and models. The study took the entire coast of Bangladesh except for Sundarbans Reserve Forest and rolled back to 1962 to work on 60 years’ time series data. Declassified CORONA satellite imagery along with Landsat satellite imagery was used, which is the first-ever attempt in the remote sensing-based ecosystem work in Bangladesh.ResultsThe study's main innovation is to spatially establish the effectiveness of the NBS. The study critically assessed and estimated stable lands and their socio-economic benefits as part of the effectiveness of the NBS. As part of the NBS-derived benefits in the context of climate change, it estimated the sequestrated carbon in mangrove forests. A significant positive relationship was observed between the increase of mangroves and stable lands. Near about 448,011 ha of agricultural land was stabilized due to the NBS intervention whose economic value is 18,837 million USD. In addition, 29,755.71 kt of carbon have been sequestrated due to NBS program.ConclusionsThe concept of NBS is still in the development stage and very little or no work has been done so far in measuring and labeling the effectiveness of the NBS. Therefore, our study can innovatively contribute to the scientific community to show the effectiveness of the NBS in three domains (social, economic and ecological) in the changing climatic scenario.

Effect of stocking density and water depth on the growth and production of red seaweed, Gracilaria tenuistipitata in the Kuakata coast of Bangladesh

Seaweed aquaculture, the quickly growing global food production segment, provides plenty of options for mitigating and adapting to developed-world conditions. In Bangladesh, the rise of seaweed cultivation gives hope for increasing incomes in fishing villages. The effect of stocking density (1, 2, 3, and 4 Kg/m2) and water depth (surface, 0.5 m, and 1.0 m) on cultivating red seaweed, Gracilaria tenuistipitata, using the square raft (1 m × 1 m) method was evaluated on the Kuakata coast of Bangladesh from December 2021 to March 2022. The raft was made of bamboo, rope, and plastic containers. Hydrological parameters and other growth indicators were monitored fortnightly. Temperature (27.3–29.5 °C), transparency (53.8–57.3 cm), salinity (18.6–21.4), pH (7.4–7.9), and dissolved oxygen (5.7–6.2 mg/L) were all found to be adequate for seaweed farming, however, salinity was somewhat lower than the ideal range. The initial stocking density of 2 Kg/m2 with a culture period of 60 days was found to be the most suitable for G. tenuistipitata than other stocking densities in terms of daily growth rate (DGR). The maximum biomass yield (13.52 ± 2.04 Kg/m2) was observed at a stocking density of 4 Kg/m2, but no significant difference (p < 0.05) was detected among stocking densities of 2, 3, and 4 Kg/m2. Furthermore, as compared to the surface and 1.0 m water depth, the daily growth rate was significantly higher at a depth of 0.5 m. However, at a water depth of 0.5 m, there was a rising trend in biomass yield, after which it declined significantly (p < 0.05). Based on the findings, the current study suggests that cultivating G. tenuistipitata at a stocking density of 2 Kg/m2 at a water depth of 0.5 m can produce greater DGR and biomass production, which might provide monetary benefits to small farmers in Bangladesh's Kuakata coast, Bay of Bengal.

Land Use Land Cover Change and Related Drivers have Livelihood Consequences in Coastal Bangladesh

Land Use Land Cover Change and Related Drivers have Livelihood Consequences in Coastal Bangladesh

How Do Left-Behind Families Adapt to the Salinity-Induced Male Out-Migration Context? A Case Study of Shyamnagar Sub-District in Coastal Bangladesh

The knowledge regarding male out-migration due to climate change and large-scale, rapid-onset disasters and their impacts on the left-behind families is well known. However, research on the adaptation strategies for the families left behind due to disaster-induced male-out seasonal migration is rarely carried out. Thus, this study attempts to explore the coping and adaptation strategies adopted by the left-behind families in the salinity-induced male out-migration context. Analyzing the factors affecting the adaptation behaviors is also a major objective of this study. The study was carried out in Shyamnagar sub-district of coastal Bangladesh, where male-out seasonal migration for both rapid and slow-onset disasters is evidenced. The data regarding the adaptation measures were explored through different participatory rural appraisal techniques. Primary data were collected from 213 women from the left-behind families through a semi-structured questionnaire. Descriptive statistics as well as multiple linear regression for analyzing the factors affecting adaptation behaviors were applied. The results revealed that the left-behind families, especially the women and children, adopted a total of 35 coping and adaptation strategies in five different aspects, such as economic adaptation, social adaptation measures, environmental measures, educational measures, and health-related measures. Migrant husbands’ age and their education, the household’s alternative income sources’ availability, receiving loans, disaster history, and migration history variables contributed most significantly to the adaptation behavior. This study provides a new perspective on seasonal male out-migration and the adaptation strategies of the left-behind families, which could be helpful for disaster-induced human migration management and enhancing the resilience of vulnerable communities.