Building Climate Resilient Fisheries and Aquaculture in Bangladesh: A Review of Impacts and Adaptation Strategies

Abstract

This study examines the impacts of climate change on fisheries and aquaculture in Bangladesh, one of the most climate-vulnerable countries in the world. The fisheries and aquaculture sectors contribute significantly to the national GDP and support the livelihoods of 12% of the total population. Using a Critical Literature Review (CLR) approach, peer-reviewed articles, government reports, and official datasets published between 2006 and 2025 were reviewed across databases such as Scopus, Web of Science, FAO, and the Bangladesh Department of Fisheries (DoF). The analysis identifies major climate drivers, including rising temperature, erratic rainfall, salinity intrusion, sea-level rise, floods, droughts, cyclones, and extreme events, and reviews their differentiated impacts on key components of the sector: inland capture fisheries, marine fisheries, and aquaculture systems. For inland capture fisheries, the review highlights habitat degradation, biodiversity loss, and disrupted fish migration and breeding cycles. In aquaculture, particularly in coastal systems, this study reviews the challenges posed by disease outbreaks, water quality deterioration, and disruptions in seed supply, affecting species such as carp, tilapia, pangasius, and shrimp. Coastal aquaculture is also particularly vulnerable to cyclones, tidal surges, and saline water intrusion, with documented economic losses from events such as Cyclones Yaas, Bulbul, Amphan, and Remal. The study synthesizes key findings related to climate-resilient aquaculture practices, monitoring frameworks, ecosystem-based approaches, and community-based adaptation strategies. It underscores the need for targeted interventions, especially in coastal areas facing increasing salinity levels and frequent storms. This study calls for collective action through policy interventions, research and development, and the promotion of climate-smart technologies to enhance resilience and sustain fisheries and aquaculture in the context of a rapidly changing climate.

1. Introduction

Climate change is reshaping human and natural systems worldwide, affecting not only ecosystems but also social formations, economies, and cultural relations [1]. The global mean surface temperature during 2006–2015 was 0.87 °C higher than that of 1850–1900. Human-induced global warming is currently increasing at a rate of 0.2 °C per decade [2]. Many natural resources have already been degraded due to rising temperature and elevated CO₂ levels, and these impacts could become irreversible if global temperatures exceed 1.5 °C [3,4,5]. The trends indicate growing environmental degradation, which is likely to exacerbate existing world issues such as poverty, inequality, and shortages of resources.

Among the countries most affected by these global changes, Bangladesh stands out as a climate hotspot [3]. Due to its low-lying deltaic topography and geographic location along the Tropic of Cancer (Figure 1), Bangladesh is particularly prone to the impacts of climate change [3,6]. This makes the country highly susceptible to a range of climate-induced hazards, including floods, droughts, cyclones, tidal surges, tornadoes, earthquakes, infrastructure collapse, waterlogging, river erosion, salinity in water and soil, epidemics, and pollution [7]. These vulnerabilities are further compounded by socio-economic pressures such as pervasive poverty, high population density, and limited adaptive capacity [8]. In response to these challenges, the Government of Bangladesh has introduced several key policy frameworks to address the impacts of climate change. Among the most significant policy initiatives are the National Adaptation Plan (NAP), the Mujib Climate Prosperity Plan (MCPP), and the Bangladesh Climate Change Strategy and Action Plan (BCCSAP). These efforts focus on agricultural innovation, infrastructure development, disaster risk reduction, nature-based solutions, community-based adaptation, and international collaboration. Despite these advancements, challenges remain, including institutional capacity gaps, social vulnerabilities, and financial constraints, highlighting the need for continued international support and cooperation [9].

Globally, fisheries and aquaculture are conceptually distinct, though in Bangladesh, aquaculture is often considered a subset of fisheries. Fisheries is the science of managing and sustainably harvesting aquatic organisms from natural water bodies. It encompasses various fields, including biology, ecology, population dynamics, conservation, economics, and management. On the other hand, aquaculture refers to the controlled farming of aquatic organisms, including fish, crustaceans, mollusks, and plants, in inland, coastal, or marine environments. This includes activities such as system design, stocking, feeding, disease control, and harvesting, typically under private or corporate ownership. Bangladesh is one of the leading fish-producing countries in the world, both from the fisheries and the aquaculture sector, with a total production of 4.91 million MT during 2022–2023 [10]. Of this, 13.82% comes from marine capture fisheries, 28.15% from inland capture fisheries, and 58.03% from aquaculture. According to the FAO 2024 [11], Bangladesh ranks 2nd in total capture fisheries production and 5th in aquaculture production. In 2024, Bangladesh declared self-sufficiency in fish production, ensuring 67.80 g of fish per capita per day, covering approximately 60% of daily animal protein intake [10]. In fiscal year 2022–2023, the fisheries sector contributed 2.43% to national GDP, 22.14% to agricultural GDP, and provided livelihoods for about 12% of the population, directly or indirectly [10].

Fish production from capture fisheries and aquaculture primarily depends on various freshwater, coastal, and marine waterbodies (

Table 1. Sector-wise annual fish production from inland and marine capture fisheries and aquaculture during 2022–2023 (adapted from [10]).

Fisheries Resource Areas	Water Area (ha)	Production (MT)	% of Total
Inland capture fisheries
River and estuary	853,863	389,035	7.92
Sundarbans	177,700	26,047	0.53
Beel	114,161	108,625	2.21
Kaptai lake	68,800	17,056	0.35
Floodplain	2,646,757	842,520	17.14
Total	3,861,281	1,383,283	28.15
Marine capture fisheries
Industrial (trawl)		146,037	2.97
Artisanal		533,348	10.85
Total		679,385	13.82
Inland aquaculture
Pond	415,872	2,272,667	46.24
Seasonal culture water body	144,513	231,582	4.71
Baor	5671	12,158	0.25
Shrimp and prawn farm	261,833	301,103	6.13
Crab	9372	12,881	0.26
Pen culture	9080	16,402	0.33
Cage culture	193,232 m3	5254	0.11
Total	84,6341	2,852,047	58.03
Country total		4,914,715	100.00

). The fish production of inland capture fisheries is from rivers and estuaries, mangrove forests (Sundarbans), beel (a wetland depression in the floodplains of Bangladesh that holds water permanently or seasonally, especially during the monsoon), Kaptai Lake, and floodplains. The major inland capture fisheries-producing waterbodies are floodplains, supplying 17.14% of the total inland fish production, followed by rivers (7.92%), beels (2.21%), and Sundarbans (0.53%) [10]. The marine fisheries contributed only 13.82% of the total production, of which 10.85% is from artisanal fisheries and 2.97% from industrial trawling. However, Bangladesh possesses 118,813 km² in the Bay of Bengal and recently achieved the sovereign right to a maritime boundary. Inland aquaculture is characterized by freshwater and brackish water (coastal) aquaculture. Freshwater aquaculture is dominated by pond aquaculture, which contributed 46.24% of the total fish production, followed by shrimp/prawn farm (6.13%), seasonal culture waterbodies (4.71%), crab culture (0.26%), pen culture (0.33%), baor (an oxbow lake formed when a river changes course, leaving a cut-off waterbody; they are common in southwestern Bangladesh, particularly in Jashore, Jhenaidah, and Chuadanga districts) culture (0.25%), and cage culture (0.11%). This indicates that aquaculture is dominated by traditional pond-based farming; however, there is a recent growth of other aquaculture systems such as crab, pen, and cage farming (Table 1).

The main driver of aquaculture production is hatchery-produced seeds, and the hatchery operation depends on various weather parameters for brood rearing, induced spawning, larval rearing, and fingerling production. Aquaculture systems at both the grow-out and hatchery levels are influenced by several climatic factors, including air temperature, water temperature, sunlight intensity, and erratic rainfall patterns. These factors can significantly impact fish development, growth, and overall hatchery productivity [12].

Carp species, including Indian major carps and other indigenous and exotic carps, collectively contributed about 36% of the total fish production during 2022–2023 (

Table 2. Species-wise annual fish production in inland and marine capture fisheries and aquaculture during 2022–2023 (adapted from [10]).

Species/Group	Inland Fish Production in MT (Both Capture Fisheries & Aquaculture)	Marine Fish Production in MT (Capture Fisheries)	Total in MT	% of Total
Major carp (Labeo rohita, Catla catla, Cirrhinus cirrhosus)	1,084,397		1,084,397	22.06
Other carp (L. bata, L. calbasu, L. gonius)	144,584		144,584	2.94
Exotic carp (Hypophthalmichthys molitrix, Ctenopharyngodon idella, Cyprinus carpio)	545,141		545,141	11.09
Pangasius (Pangasianodon hypophthalmus)	403,283		403,283	8.21
Other catfish (Heteropneustes fossilis, Clarias batrachus)	76,000		76,000	1.55
Snakehead	81,092		81,092	1.65
Live fish	184,314		184,314	3.75
Tilapia (Oreochromis spp.)	421,191		421,191	8.57
Other inland fish	666,642		666,642	13.56
Crab (Scylla serrata, S. olivacea)	12,881		12,881	0.26
Hilsa (Tenualosa ilisha)	271,330	300,012	571,342	11.63
Shrimp and Prawn (Penaeus monodon, Macrobrachium rosenbergii)	224,539	46,763	271,302	5.52
Sardine (Sardinella fimbriata)		51,500	51,500	1.05
Bombay duck (Harpadon nehereus)		81,942	81,942	1.67
Indian salmon (Polydactylus indicus)		200	200	0.00
Pomfret		12,052	12,052	0.24
Jewfish (Otolithes ruber)		42,754	42,754	0.87
Sea catfish (Tachysurus spp.)		15,305	15,305	0.24
Shark/Skate/Ray		3351	3351	0.07
Tuna and Tuna-like fish		15,051	15,051	0.31
Other marine fish		110,455	110,455	2.25
Total (MT)	3,496,958	637,476	4,134,434	100.00
% of total	84.58	15.42	100

). The main carp species that contribute to aquaculture production are Rohu (Labeo rohita), Catla (Catla catla), Mrigal (Cirrhinus cirrhosus), Kalibaus (L. calbasu), Bata (L. bata), Gonia (L. gonius), Silver carp (Hypophthalmichthys molitrix), Grass carp (Ctenopharyngodon idella), Common carp (Cyprinus carpio), and other exotic carps [10]. The species-wise contribution to national fish production is dominated by Major carp (22.06%), pangasius (8.21%), Hilsa (11.63%), tilapia (8.57%), and shrimp/prawn (5.52%). Out of these species, carps, pangasius, tilapia, and shrimp/prawn are farmed by different aquaculture systems, and only Hilsa is captured from the open water fisheries in both inland and marine waterbodies (Table 2).

In terms of marine catch, Bombay duck (Harpondon nehereus) and Jewfish (Otolithes ruber) are the dominating species. This scenario indicates that fish production from aquaculture and capture fisheries is dominated by freshwater fish species by volume and individual species contribution. Capture fisheries, which rely on natural ecosystems with minimal human intervention, are particularly sensitive to changes in primary production and aquatic food chains, making them highly exposed to climate-induced disruptions [13].

However, the biophysical characteristics of different types of inland waterbodies, including hydrology, water availability, species diversity, and seasonality of fish breeding and migration, are affected by various climatic variables, particularly temperature, rainfall, floods, cyclones, and salinity. Additionally, extreme weather events, such as sea surface temperature, cyclones, wind patterns, and ocean currents, significantly impact marine capture fisheries, further affecting the lives and livelihoods of artisanal fishers in the Bay of Bengal [14].

Despite these potential risks, existing research on the impacts of climate change on the fisheries and aquaculture sectors of Bangladesh remains limited, often focusing on specific events or localized impacts [8,15]. There is a critical gap in comprehensive, nationwide assessments that analyze all relevant climate hazards and their compounded effects on the fisheries and aquaculture industries. Given the high vulnerability of the fisheries and aquaculture sectors of Bangladesh to multiple climate extremes, a holistic approach is essential for assessing climate risks and formulating targeted adaptation strategies. Such an approach would enable the identification of the most at-risk communities, ecosystems, and production systems, guiding the design of localized and effective adaptation measures. These would aim to reduce vulnerabilities, enhance sectoral resilience, and promote sustainable and climate-resilient fisheries and aquaculture practices. In this context, the present study aims to examine the multifaceted impacts of climate change on the fisheries and aquaculture sectors of Bangladesh and propose key adaptation strategies to inform research and development (R&D) initiatives. It synthesizes knowledge from several key areas, including an overview of the fisheries and aquaculture sectors of Bangladesh, the broader context of climate change, its main driving forces, impacts on aquatic ecosystems, and strategies for mitigation and adaptation in both capture fisheries and aquaculture.

2. Methodology

This study is based on a review of published literature, focusing on the impacts of climate change on fisheries and aquaculture in Bangladesh. The study utilizes secondary data from a range of authoritative sources, including peer-reviewed journals, government reports, and institutional publications. A total of 75 peer-reviewed journal articles and 15 reports were examined to collect the necessary information. Additional supporting data were obtained from institutional sources, including the Bangladesh Fisheries Research Institute (BFRI), the Food and Agriculture Organization (FAO), the Bangladesh Bureau of Statistics (BBS), the World Bank, the Department of Fisheries (DoF), Online news portals, and other publicly available materials from both governmental and non-governmental organizations. Literature searches were carried out mainly through Scopus, Web of Science, and Google Scholar using keywords such as ‘climate change impacts’, ‘fisheries Bangladesh’, ‘aquaculture adaptation’, ‘climate resilience, flood and drought effects Bangladesh’, ‘coastal vulnerability Bangladesh’, ‘climate-smart aquaculture’, and ‘climate adaptation Bangladesh’. The review was limited to English-language, peer-reviewed publications published between 2006 and 2025 (

Table 3. The study’s eligibility and exclusion criteria.

Criterion	Description
	Inclusion	Exclusion
Time frame	After 2006	Before 2006
Type of Language	English	Non-English
Type of Literature	Peer-reviewed literature, government, and organizational reports	None
Area of Content	Climate change impacts, resilience building, adaptation, and mitigation strategies in fisheries and aquaculture	Non-aquaculture or non-fisheries sectors
Publication Status	Published and available online	Published but not accessible, unpublished manuscripts
Geographic Coverage	Focus on Bangladesh, with reference to regional/global comparative studies where relevant	None
General Topics	Climate change affects fisheries and aquaculture, vulnerability assessment, adaptive practices, livelihood resilience, governance, and policy interventions	Topics unrelated to climate change or resilience in fisheries/aquaculture
Methodologies	Empirical studies (field surveys, experiments, modeling), policy analyses, reviews, and syntheses	Studies lacking methodological clarity or without a focus on resilience/adaptation

).

Collected data were analyzed using the Critical Literature Review (CLR) method to synthesize and combine significant information related to the study objectives [16,17]. The CLR process involved several steps: topic formulation was first conducted to delimit the scope of review; secondly, a full review of published documents, including journal articles, books, reports, and conference proceedings was carried out; thirdly, appropriate lessons were selected, comparisons were made, and the most relevant information was selected; and finally, the findings that were derived were synthesized to provide insights aligned with the study objectives. This structured approach enabled the identification and synthesis of key information, providing a comprehensive understanding of the impacts of climate change on Bangladesh’s fisheries and aquaculture sectors and meeting the objectives of this manuscript.

3. General Overview of Climate Change in Bangladesh

Bangladesh’s climatic variability is largely influenced by its unique geographic setting, characterized by extensive floodplains, low elevation above sea level, and significant dependence on natural resources. These vulnerabilities are further exacerbated by anthropogenic activities, a densely populated landscape, and widespread poverty [18]. Consequently, Bangladesh consistently ranks among the world’s most climate-vulnerable nations. Between 2000 and 2019, Bangladesh experienced 185 extreme weather events, highlighting its acute vulnerability [19]. The ND-GAIN Index highlights critical variations in vulnerability and readiness across countries, thereby positioning them within a matrix of adaptation needs and urgency. Bangladesh, ranked 178th, is the 18th most vulnerable country with very low readiness, placing it in the upper-left quadrant of the ND-GAIN Matrix, where urgent investment and innovation are required. By contrast, Vietnam (Rank 96) and India (Rank 115) fall within the upper-right quadrant, combining high vulnerability with relatively higher readiness, which signals progress yet underscores substantial adaptation needs. Japan (Rank 19) and the Republic of Korea (Rank 15) are among the least vulnerable and most prepared, reflecting strong adaptive capacity. Conversely, Nepal (Rank 126) demonstrates high vulnerability and low readiness, while China (Rank 36) exhibits moderate vulnerability but comparatively strong readiness, pointing to significant capacity for climate risk management with continued investment [20].

These findings align with the Global Climate Risk Index (2000–2019), which identifies the countries most affected by extreme weather events over two decades. Puerto Rico, Myanmar, and Haiti were the three most impacted, followed by the Philippines, Mozambique, and the Bahamas. Bangladesh ranked 7th, reflecting its chronic exposure to cyclones, floods, and sea-level rise, while Pakistan, Thailand, and Nepal completed the top ten. Together, the ND-GAIN and CRI rankings underscore that while some countries possess strong readiness to address climate risks, nations such as Bangladesh and Nepal remain extremely vulnerable, facing an urgent need for adaptation measures to mitigate the compounded effects of climate change on development trajectories [19].

Bangladesh is exposed to multiple climatic hazards, including cyclones, floods, droughts, sea-level rise, salinity intrusion, and erratic rainfall patterns [21]. These challenges are exacerbated by rising global temperature due to greenhouse gas emissions, intensifying monsoonal variability, increasing evaporation rates, and contributing to higher humidity. Temperature trends in Bangladesh reflect this global warming trajectory. According to recent literature, maximum summer temperature frequently range between 30 °C and 40 °C [22]. Long-term analyses reveal a significant upward trend: the average temperature rose modestly from 30.27 °C (1950–1975) to 30.36 °C (1976–2000), increasing by 0.09 °C, while the period from 2001 to 2023 saw a sharp rise to 30.95 °C, a 0.59 °C increase compared to the previous interval [23]. Jihan et al., 2025 [24] revealed that, from 1901 to 2020, Bangladesh experienced a significant warming trend, with an average increase in temperature of 2 °C. Concurrently, there was a decline in overall precipitation by 607.26 mm, contributing to a shift towards drier conditions, despite weak correlations with hotter years. Future projections indicate that by 2100, the minimum temperature in Bangladesh is expected to rise by 1 °C to 4.4 °C, while the maximum temperature is projected to increase by 1 °C to 4.1 °C. Moreover, future precipitation is expected to rise by 480.38 mm, with the most substantial increases occurring during the monsoon months. Regional variations in temperature and precipitation are also anticipated, with the Southeast (SE) region expected to experience the first significant warming, while the Northeast (NE) is predicted to see the highest increase in precipitation.

Recent CMIP6 and CORDEX-based projections provide robust insights into future risks for the Bay of Bengal and Padma–Meghna basins. Hydrological modeling for the Upper Meghna River Basin (UMRB) using SWAT, driven by thirteen bias-corrected CMIP6 GCMs under SSP2-4.5 and SSP5-8.5, projects a continuous rise in annual maximum flows. The Meghalaya sub-basin is expected to experience greater increases than the Barak and Tripura sub-basins, with dry season flows projected to rise by 31–50% and wet season flows by 47–66% by the end of the century, accompanied by more frequent and intense flood events [25]. In a separate analysis, hydrological simulations for the Teesta–Brahmaputra system using SWAT with 13 bias-corrected CMIP6 GCMs and HEC-RAS frequency analysis show marked increases in discharge. Results indicate that 100-year return water levels in the Jamuna will increase from 38 cm in the near future (2025–2054) to 83 cm in the far future (2071–2100), while the Old Brahmaputra, Dharala, and Brahmaputra rivers are projected to rise by 25–90 cm, reflecting intensified flood risks [26].

Another study applied a hydrological model driven by bias-adjusted ensembles of CMIP6 (SSP5-8.5/SSP1-2.6) and CMIP5 (RCP8.5/RCP2.6) climate projections to assess future flood risks in the Ganges, Brahmaputra, and Meghna basins. Results show average increases in peak flow magnitudes of 36% under SSP5-8.5 (SSP1-2.6) by 2070–2099, compared with 60% under RCP8.5 (RCP2.6). The Ganges basin faces the earliest and sharpest rise, with extreme floods becoming the “new norm” by mid-2030, while Brahmaputra and Meghna show later signals after 2070. Overall, robust increases in flood magnitude and synchronization highlight the urgency for climate mitigation, adaptation, and transboundary cooperation to strengthen resilience in Bangladesh [27]. At the coastal scale, long-term tidal and deltaic gauge records combined with satellite altimetry reveal that sea-level rise along Bangladesh’s coast is occurring at much higher rates than regional and global averages. Projections suggest rises of 228–608 mm by 2050 and 435–1162 mm by 2100 at Cox’s Bazar, while deltaic sites such as Kalaroa and Benarpota show extreme rates exceeding 40 mm/yr, reflecting the amplifying influence of land subsidence and sedimentation [27]. Rainfall extremes are also expected to intensify. CORDEX–South Asia downscaled simulations analyzed through the Bayesian Model Averaging project show increases of 12.93–18.42% in pre-monsoon rainfall under RCP4.5 and 18.18–23.85% under RCP8.5, alongside monsoon increases of 2.27–6.56%. Most extreme rainfall indices, except consecutive wet days, are projected to change significantly at the 95% confidence level, particularly heightening flash flood risks in the pre-monsoon [28]. Finally, CMIP6 simulations of the North Indian Ocean indicate strong SST warming, with an increase of nearly 3 °C under SSP5 compared to SSP2 during 2060–2099. The Bay of Bengal is projected to remain 0.5 °C cooler than the Arabian Sea but still warm substantially, with changes in surface heat flux and cloud cover further enhancing sea surface temperature rise [29].

The monthly climatology (1991–2023) further emphasizes Bangladesh’s pronounced seasonal variability in temperature and precipitation (Figure 2). Average maximum temperatures peak around 34 °C during April–May, whereas minimum temperatures drop to approximately 11 °C in January [30]. Precipitation rises sharply starting in May, reaching a maximum of approximately 500 mm in July, coinciding with the peak monsoon. This pattern highlights climate change-induced shifts, characterized by warmer summers and increasingly erratic rainfall. Chowdhury et al., 2010 [31] projected that between 1995 and 2100, Bangladesh would experience an increase in annual temperature of approximately 1 to 2.4 °C and a rise in annual precipitation by 3.5 to 9.7%. However, during winter, temperatures are expected to increase by 1.1 to 2.7 °C, while precipitation is anticipated to decline by around 3%, consequently leading to higher evapotranspiration rates. These climatic patterns directly threaten fisheries and aquaculture by disrupting fish breeding cycles, reducing dissolved oxygen levels, and increasing fish mortality.

Prolonged high temperatures, heavy rainfall, and flooding events exacerbate risks such as disease outbreaks and shifts in gher (an enclosed waterbody, usually a modified paddy field, used for shrimp/fish farming in coastal Bangladesh) salinity, undermining sustainable fisheries and aquaculture production. Coastal regions face compounded risks due to sea-level rise and increased salinity intrusion. In southern Bangladesh, projected sea-level rise is expected to displace approximately 0.9 million people by 2050 [32]. Saline water intrusion threatens freshwater availability, disrupts fisheries, and disproportionately affects coastal communities dependent on fish as a vital protein source [33]. Long-term data from the Soil Resource Development Institute indicate a significant expansion of saline-affected areas in coastal districts between 1973 and 2009 (Figure 3). In Khulna, salt-affected areas increased by 23.3% (120.04 to 147.96 thousand hectares). Similarly, Bagerhat saw an increase of 21.42% (107.98 to 131.12 thousand hectares). Jashore, historically unaffected, has recently begun experiencing salinity intrusion [34].

These climatic and environmental changes pose serious threats to fisheries and aquaculture sectors that are crucial for food security and livelihoods in Bangladesh. The observed changes in temperature, rainfall, humidity, and salinity in Bangladesh are driven by several factors. Rising global temperatures due to greenhouse gas emissions have intensified monsoonal variability, increased evaporation rates, and contributed to higher humidity and erratic rainfall. Sea level rise, tidal intrusion, and reduced freshwater flow during dry seasons, exacerbated by irregular rainfall, have expanded salt-affected areas. These changes pose severe challenges for agriculture, fisheries, and aquaculture, threatening yields and food security in coastal regions.

4. Impacts of Climate Change on Fisheries and Aquaculture

Bangladesh is particularly vulnerable due to its vast delta plain, which is crisscrossed by many rivers, many of which experience unstable swelling during the monsoon rains. This unique geography, coupled with river water from the melting Himalayan glaciers to the north and the encroaching Bay of Bengal to the south, makes the region highly susceptible to severe flooding. The situation is further exacerbated by intense storms, which are indicators of climate-induced stress. According to available literature, very few studies have been performed on climate change impacts related to fisheries and aquaculture in Bangladesh. However, climatic drivers exert both direct and indirect effects on fisheries and aquaculture, making it challenging to precisely predict their influence on different fish species in capture and culture systems (Figure 4).

The major and common extreme climate events in Bangladesh can therefore be broadly classified as cyclones and tidal surges, floods and flash floods, droughts, salinity intrusion with sea-level rise, erratic rainfall and heatwaves, and river erosion with siltation. Each of these hazards exerts specific pressures on fisheries and aquaculture, ranging from pond and gher destruction, broodstock and fry mortality, and hatchery disruption, to habitat degradation, disease outbreaks, and blocked migration routes of species such as Hilsa.

Case studies of extreme climate events provide important insights into these vulnerabilities. For instance, in November 2007, Cyclone Sidr, a Category 4 storm, devastated southern Bangladesh, claiming the lives of around 3500 people, displacing 2 million, and destroying vast areas of culture fields. This disaster was followed by two exceptionally severe floods that resulted in the deaths of approximately 1500 people and caused the destruction of nearly 2 million tons of food [35]. Bangladesh consists of 64 districts, each with its own distinct geography and climate. The northwestern region has faced prolonged droughts induced by climate change, while the central and northeastern regions have been affected by flooding, flash floods, and river erosion. Coastal areas have experienced tidal surges, waterlogging, saltwater intrusion, and the impacts of rising sea levels [36,37].

Around 9592 hectares of fishing enclosures containing 24,672 ponds and shrimp farms were damaged by cyclone Yaas, with an estimated loss of USD 7.09 million (1 USD = 117 BDT) [38]. Similarly, the mean loss and damage per shrimp farm was calculated at USD 4633 during cyclone Bulbul. Approximately 31% of fencing nets and 72% of traps in shrimp farms were destroyed, with an average replacement cost of USD 333 per farm [39].

The severe cyclonic storm Remal caused financial losses amounting to USD 73.33 million across the fisheries sector. The damage included the inundation of ponds, enclosures, hatcheries, shrimp farms, fish fry production units, and crab culture systems across 88 upazilas of 16 coastal districts under the Khulna, Barisal, Chittagong, and Dhaka divisions of Bangladesh. The cyclone directly affected fisheries production of more than 20,523 MT of finfish, 7943 MT of shrimp, 1627 MT of fish fry, 253 MT of crab/Kuchia, and 590 MT of shrimp post-larvae (PL) [40]. Primary estimates further indicate a combined loss of about USD 26.15 million in the fisheries and livestock sectors of Barisal and Khulna divisions, with more than 24,350 fish farms completely washed away by the Amphan [41]. However, climate change may have several implications for fisheries and aquaculture, which are discussed.

4.1. Impacts on Capture Fisheries

4.1.1. Impacts on Fish Habitats

As a deltaic country, Bangladesh is interlaced with numerous rivers that historically played a vital role in sustaining aquatic ecosystems. However, the number and flow of rivers have declined significantly over time due to both natural and anthropogenic factors. Rivers are highly sensitive to environmental changes [42]. Shahid et al., 2024 [43] demonstrated how geomorphological changes over the past 32 years, driven by natural processes and human interventions, have reshaped the country’s coastline and river systems. Their remote sensing and GIS-based analysis highlights severe erosion in the Meghna Estuary, relative stability along the Sundarbans coast, and altered river morphologies due to upstream flow reductions and structural interventions, underscoring the urgent need for sustainable river and land management. Currently, 190 rivers in Bangladesh are classified as moribund, with 99% having lost their original depth. At the onset of the dry season, water flow diminishes in nearly all 761 rivers, severely degrading riverine ecosystems. This degradation disrupts the associated aquatic environment, such as haors (a large bowl-shaped floodplain wetland in northeastern Bangladesh, notably in Sunamganj, Kishoreganj, Netrokona, and Habiganj districts), baors, canals, beels, and floodplains. Continuous siltation in rivers and estuaries has a negative impact on fish habitats by reducing water quality, altering breeding grounds, and limiting species movement. Siltation in the beels has significantly contributed to the decline of haor fisheries by degrading the natural environments of fish [44]. Land-use changes in the upper riparian zones have accelerated sedimentation in the haor region, disrupted the ecological balance of the Jadukata-Patlai River system [45], and adversely affect fish species diversity by obstructing migration pathways and causing the disappearance of small beels that once served as essential feeding grounds [46]. Additionally, climate-induced events such as droughts, excessive rainfall, flash floods, and salinization further degrade these natural environments. Indian major carps (e.g., L. rohita, C. catla) are highly vulnerable to changes in rainfall patterns and flood regimes, which affect their growth and reproduction, leading to significant broodfish mortality and destruction of breeding grounds [47,48]. Flash floods and siltation reduce river navigability, while droughts result in habitat contraction. Cyclones and floods can damage aquaculture infrastructure, inundate ponds, and lead to the loss of stocked fish, further threatening the sustainability of fish populations in both natural and cultured environments [49]. Rivers serve as a vital resource for inland capture fisheries in Bangladesh; however, they are experiencing reduced water levels due to inadequate rainfall during the monsoon season. As a result, fishing pressure on the rivers in Bangladesh has increased, exacerbating the strain on fish populations and threatening the sustainability of these vital ecosystems [50]. Although many of these pressures originate from anthropogenic drivers such as land-use change, water diversion, and sedimentation, climate-induced stressors, including droughts, erratic rainfall, flash floods, and salinization, act as compounding factors. Thus, the observed decline in fishery production is best explained as the outcome of both human interventions and climatic variability, rather than climate change alone.

4.1.2. Reduced Fish Biodiversity

Climate change has emerged as a major driver of declining fish biodiversity in aquatic environments of Bangladesh, as evidenced by the increasing frequency of flash floods (e.g., in haor regions) and erratic hydrological patterns. Several studies converge on the trend of species loss, though they differ in focus and geographic scope [15]. Akhter and Rahman, 2016 [47] offered a regional perspective, documenting fish extinctions across major river systems in Rajshahi, Khulna, Dhaka, Barisal, Sylhet, and Chittagong, with species loss ranging from 28 to 37. The corresponding declines in natural production, affecting up to 102 species in some regions, underscore the spatial heterogeneity of ecological impacts. Although these studies differ methodologically, with some relying on observational field data and others on species distribution records, they reinforce a shared concern: climate-induced disruptions such as altered flow regimes and habitat degradation are driving widespread ecological shifts. Moreover, Roy et al., 2019 [51] found that climate change has led to a 21.25% loss in fish biodiversity in Dekhar haor, with significant losses in various species, including carps (16.67%), catfishes (27.27%), and loaches (33.33%). Local communities observed abrupt changes in weather over the past decade, with high temperature identified as the primary factor. Climate factors such as temperature, rainfall, and drought have led to shifts in breeding seasons and variations in fish growth and taste.

Akther et al., 2024 [52] identified a sharp decline in the spawning success of Indian major carps (IMCs) in the Halda River in 2021. Egg production dropped to 8580 kg and fry yield to 105.73 kg, representing reductions of 66% and 73.3%, respectively, compared to 2020. Environmental stressors contributing to this decline included rising temperatures (90% of observed variation), reduced rainfall (86%), decreased hill water runoff (84%), and saline intrusion (76%). Anthropogenic disturbances were significant: pollution (76%), river bend cutting (80%), rubber dam installations (78%), and abandoned sluice gates (84%) were found to exacerbate spawning challenges. These results underscore the combined impacts of climatic and anthropogenic factors on IMC spawning failure in the Halda River. Moreover, Species like Tilapia (Oreochromis spp.), Shing (H. fossilis), Pangus (P. hypophthalmus), and Climbing perch (Anabas testudineus) are particularly vulnerable to the impacts of climate change, especially in terms of the scarcity of wild seeds. These species, being highly sensitive to temperature and water quality fluctuations, face challenges in both natural habitats and hatchery environments. The increase in water temperature, changes in rainfall patterns, and salinity intrusion significantly affect their breeding cycles and survival rates. Hatchery owners also face significant difficulties in maintaining optimal conditions for seed production, resulting in lower availability of quality seeds for aquaculture [12,53,54]. Collectively, the literature reveals a clear trend of biodiversity erosion, while also pointing to the need for more integrated, longitudinal studies that examine not just species counts but ecological function, hydrological dynamics, and socio-economic consequences.

4.1.3. Fish Migration

Climate change exerts a substantial influence on the migratory behavior of both freshwater and marine fishes, primarily through its effects on temperature, rainfall, and hydrological regimes. Multiple studies agree that alterations in these variables disrupt established migratory routes and spawning grounds, yet they offer differing regional and species-specific insights. Akhter and Rahman, 2016 [47] documented a significant shift in the spawning behavior of Indian major carps, such as Rohu, Catla, Mrigal, and Kalibaus, whose historical spawning grounds in the 1940s included key Bangladeshi rivers like the Halda, upper Meghna, Brahmaputra, and Padma. Over the decades, however, these fish have increasingly shifted their spawning activity upstream into Indian river systems, including the Barak River in Manipur, the Brahmaputra in Assam, and the Badhua and Mahananda Rivers in Bihar. These upstream regions in India could be more favorable due to relatively stable hydrological conditions, such as better water flow, suitable temperature ranges, and less salinity intrusion, compared to downstream areas in Bangladesh. Increased sedimentation, altered flood regimes, and water quality degradation in Bangladesh’s rivers may have diminished their suitability for spawning. This geographic displacement suggests a climate-induced alteration of hydrological cues and water quality parameters are critical for spawning.

Supporting this trend, local-level observations in the Halda river reveal that the carps’ spawning zones have migrated downstream from Nazirhat bridge in the 1950s–60s to Gorduara Madunaghat in recent years, likely due to siltation, flow reduction, and temperature changes. More likely identical pattern has been noticed in the case of Hilsa (T. ilisha), an anadromous fish that historically migrated from the Bay of Bengal to over 100 Bangladeshi rivers for spawning and nursery. Nevertheless, as noted by Shohidullah (2015) [55], river-mouth sedimentation, particularly around the Meghna off Chandpur, has increasingly closed off these migration routes, severely diminishing Hilsa’s access to upstream habitats and short-circuiting its life cycle. Although these studies agree on the trend of migratory disruption, there is a notable lack of empirical work examining the physiological thresholds or hydrological tipping points that trigger such behavioral changes. Most evidence is based on field observations or historical comparisons, with limited integration of long-term hydrometeorological data or modeling approaches. Therefore, further interdisciplinary research is urgently needed to explore subtle and species-specific responses to climate stressors, with a particular focus on identifying lost or altered migratory corridors and their implications for fisheries management and conservation planning.

4.1.4. Water Quality and Productivity

Temperature fluctuations and dissolved oxygen (DO) levels play a pivotal role in regulating plankton productivity, which forms the base of the aquatic food web. According to FAO, 2018 [56], climate-induced increases in water temperature have been consistently linked to disruptions in primary productivity, particularly phytoplankton, which directly affects the availability of food for fish and the overall functioning of aquatic ecosystems. Siddique et al., 2022 [12] further emphasized that elevated temperature not only reduce DO concentrations but also deteriorate water quality, creating stressful environments that suppress fish growth and elevate the risk of disease outbreaks. The consensus across studies suggests that temperature and DO are closely intertwined drivers of aquatic health, yet methodological variations persist. A less commonly discussed, yet significant, implication is that changes in phytoplankton productivity could also reduce the ocean’s ability to sequester carbon, as phytoplankton play a major role in carbon uptake. This introduces a feedback loop where diminished productivity not only harms fisheries but also weakens the ocean’s climate regulation function, potentially accelerating climate change itself. Despite this emerging concern, limited research in Bangladesh has explored this linkage between primary productivity, fisheries output, and carbon cycling, underscoring a gap that warrants further investigation using integrated biogeochemical and ecological models. While water quality and productivity are essential for sustaining healthy fish populations, climate change also disrupts reproductive success, as changes in temperature and water conditions directly impact fish breeding behaviors and reproductive cycles.

4.1.5. Breeding Ground

Climate change-induced shifts in temperature and precipitation patterns have had severe implications for the reproductive success and survival of freshwater fish species in Bangladesh. A consistent finding across studies is that excessive temperatures and insufficient rainfall during key reproductive periods hinder gonadal development, fertilization, embryonic growth, and overall survivability [47,57]. Long-term climatic data for the Tanguar Haor region show a rise in mean temperature by 1.4 °C from 1981 to 2010, and a concomitant reduction in rainfall of 25 mm from 1980 to 2008, resulting in degradation of aquatic environments and reduction in capture fisheries production [58,59]. One of the major trends is the geographic shift in spawning areas of principal species such as Hilsa. While previously consistently occurring in different river systems, Hilsa now primarily spawn in lower estuarine environments such as Hatia, Sandwip, and Bhola. According to Shohidullah (2015) [55], this shift is the result of climate-driven stressors, including increased flooding, tidal surges, and salinity intrusion. Most alarming is the delayed migration of the brood fish due to disrupted seasonal cues. Historically triggered in late February or early March, the migration has increasingly been delayed by water deficit and unpredictable rainfall. Siltation, which is normally augmented by short bursts of heavy rain, has also increased the difficulty by degrading critical spawning areas. Akhter and Rahman, 2016 [47] referred to the disappearance of the Kalikapur river in Noakhali (Gonia breeding ground) and the Bangali river in Bogura (Rohu breeding ground) as a result of sedimentation. Sediment-filled necessary migration routes, particularly in Haor ecosystems, with increasing river channels being obstructed, and the fish are losing their breeding chances altogether. While the majority of studies are consistent in recording adverse impacts of climate variability on fish reproduction, divergence is observed in the magnitude and causes that they prioritize; some emphasize regional hydrology, while others on thermal stress. Despite these variations, the overarching implication is clear: without urgent interventions to manage water flow, reduce siltation, and protect critical breeding habitats, both capture fisheries and hatchery systems face a stark decline in productivity. Future research should focus on modeling fish reproductive responses under different climate scenarios and developing adaptive breeding calendars that align with shifting environmental conditions.

4.1.6. Hatching Eggs and Larval Development

Fish eggs and early larval stages are among the most thermally sensitive phases in a fish’s life cycle, making them particularly vulnerable to the impacts of rising water temperatures. Siddique et al., 2022 [12] observed that elevated temperatures accelerate sexual maturation and alter the spawning timing, potentially disrupting seasonal synchrony and reproductive success. Supporting this, Wu (2009) [60] highlighted that thermal stress not only reduces dissolved oxygen, an essential parameter for embryonic development, but also leads to reproductive behavioral changes, reduced fertilization and hatching success, and even endocrine disruption in fish species. Similar vulnerabilities are observed in shrimp aquaculture, where water temperatures above 32 °C have been linked to high mortality rates in post-larval stages and increased susceptibility to algal blooms, which in turn suppress shrimp growth by degrading water quality [61]. However, some studies report conditional benefits: in West Bengal fish hatcheries, for instance, elevated temperatures led to the advancement and extension of the breeding window of Indian major carps by 45–60 days, suggesting that warmer conditions could enhance productivity under optimal water quality.

Nevertheless, such benefits are fragile in natural systems, where increased rainfall and flooding due to climate change have been shown to cause major disruptions. Irregular floods alter freshwater salinity and increase river flow velocity, physically damaging larvae and juvenile fish. Akhter and Rahman, 2016 [47] documented that siltation at key river junctions, such as where the Baral, Gorai, Nabaganga, and Madhumati meet the Padma, and where Louhajang, Bangshi, and Ichamati river flow into the Jamuna, has obstructed larval feeding grounds for species like Rohu and other carps. These findings point to a broader ecological imbalance where climatic variability, coupled with poor sediment and flow management, jeopardizes the survival of early life stages in capture fisheries. While research consistently links elevated temperatures to altered breeding behavior and reduced reproductive success, contradictions arise when considering managed systems like hatcheries, which may temporarily benefit. This suggests the need for more nuanced, species- and system-specific studies that consider thresholds for thermal tolerance, hydrological dynamics, and adaptive aquaculture infrastructure to mitigate risks. In addition to the disruptions in breeding, climate change also significantly affects early life stages, including egg development and larval survival, as temperature fluctuations and water quality changes continue to undermine reproductive processes.

4.1.7. Growth and Yield

Increased ocean temperature and thus changing ocean currents, as well as increased water acidity due to more dissolved carbon dioxide, may affect the marine fisheries by reducing catch. Higher ocean acidity makes water quality harder for fish to develop skeletons and shells, and may stop the growth of corals, which provide nurseries for fish larvae [14] Since rivers and their associated aquatic life have a central role in sustaining the inland fishery of Bangladesh, there is every necessity for large-scale research and development to address the interacting impacts of climate change on riverine ecosystems and fish diversity. Bangladesh, as a delta nation, faces severe problems such as siltation of rivers, decline in the flow of water, salinity, and degradation of critical ecological niches due to asymmetric rainfall, excessive flooding, and rising temperatures. Degradation of spawning and nursery grounds, and obstruction of fish migratory routes have contributed to the unprecedented decline of most of the freshwater fish species, including Indian major carps and Hilsa. Programs need to target specific environmental changes in river systems, mapping and restoring critical fish habitats, and creating sustainable water management to restore river flows and reduce siltation. Further research is required to understand the physiological and reproductive responses of key fish species to fluctuating temperature, altered salinity, and changing hydrological regimes. Development of adaptive breeding technologies, such as climate-resilient brood stock and hatchery innovations, is also critical to counteract the decline in natural fish reproduction. Moreover, community-based river restoration projects, combined with improved forecasting of extreme weather events, can play a vital role in sustaining fisheries productivity and protecting the livelihoods dependent on riverine resources. Addressing these challenges requires an integrated R&D approach that incorporates hydrology, fisheries biology, and climate science to formulate evidence-based policy interventions for ensuring the long-term sustainability of inland capture fisheries of Bangladesh.

4.2. Impacts on Aquaculture

According to the growing literature, climate change is expected to impact aquaculture farming practices, with the impacts potentially attributed to single or multiple facets of climate change.

4.2.1. Disease Outbreak

Climate change significantly increases physiological stress in aquatic organisms, thereby heightening their vulnerability to diseases across all life stages, from seed production to marketable growth. The literature widely agrees that temperature fluctuations caused by climate change directly affect disease susceptibility and enhance pathogen virulence [53]. Despite these global insights, climate-induced disease dynamics remain a largely underexplored research area in Bangladesh, where anecdotal and farm-level evidence suggests growing disease prevalence in both finfish and shrimp production. A review of temperature-dependent disease-causing agents reveals an ominous pattern: major aquaculture diseases are closely associated with very specific thermal thresholds, and these are augmented by means of global warming. For example, Spring viremia of carp virus typically infects juveniles above 22 °C, as reported in earlier studies [62], and Koi herpesvirus becomes prevalent within a narrower temperature range (16–25 °C) [63]. Parasites and protozoans are also benefiting from warming waters. Studies by Macnab and Barber (2012) [64] as well as by Blanco and Unniappan (2022) [65] demonstrated that climate-driven increases in temperature not only enhance the infectivity and reproductive rates of these organisms but also prolong their seasonal activity, thereby increasing cumulative disease pressure on aquaculture systems. Ahmed and Diana (2015) [66] reported that floods facilitate the entry of predatory and wild fish into shrimp farms, potentially introducing diseases and parasites. Furthermore, rising water levels and increased salinity have contributed to a higher prevalence of shrimp diseases. The gradual effects of climate change are also altering the coastal environment, leading to changes in salinity levels, which are expected to further impact the prevalence of shrimp diseases in Bangladesh [8,67].

Despite ample evidence linking temperature with pathogen virulence, few studies integrate hydrological parameters such as DO, salinity, and nutrient load, which interact with temperature to influence disease outcomes. This lack of ecological integration represents a methodological gap and hinders the design of effective early warning or prevention systems. The findings from Islam et al., 2024 [68] indicate that between 2011 and 2021, Bangladesh experienced an estimated economic loss of approximately USD 140 million in hatcheries, open water fisheries, and shrimp farming. When validated with a year of official country-wide data on climate-induced economic losses to aquaculture, the reported damage from these media sources accounts for roughly 10% of the actual losses. Based on this estimate, the potential economic value of addressing climate-induced stresses in aquaculture (CIS) could reach up to 14 million USD annually, provided that 10% of the damage can be mitigated through appropriate services and multi-sector efforts aimed at scaling such interventions to farmers. Subhani et al. (2021) [69] also reported that saline intrusion in soil and water, caused by tidal surges, damaged aquaculture activities. Given the economic importance of this sector, future research should prioritize climate pathogen interaction modeling, farm-level disease surveillance, and adaptive biosecurity protocols to mitigate emerging threats in Bangladesh’s aquaculture sector.

4.2.2. Impacts on Reproductive Seasonality

The spawning patterns of major finfish species in Bangladesh, particularly those reared in hatcheries, such as carps, tilapia, and pangasius, are closely linked to seasonal rainfall patterns. Hatcheries usually rely on natural brood sources, of which the Halda River, for example, has been a key source of good-quality brood carp [70]. Disruptions in rainfall and flood cycles have affected the natural breeding seasons of Indian major carps, which have influenced seed availability in hatcheries [71]. Bangladesh’s aquaculture is primarily hatchery-dependent, with a total of 1119 hatcheries. Of these, 1007 are privately owned, and 112 are government-owned, collectively providing 99.35% of the total seed. Only 0.65% of the seed is sourced from natural sources [10]. Because fish are cold-blooded and their physiology is temperature-dependent, seed production is highly seasonal. Different grow-out farmers demand seed at varying times, based on species and farming cycles. Species like tilapia have a defined breeding window that corresponds to optimal thermal conditions. As a result, hatcheries for this species typically operate from February to November, aiming to achieve peak production during the months with the most favorable temperatures [22] (

Table 4. Seasonality of hatchery-based fish seed production in Bangladesh.

Type of Species	Jan	Feb	Mar		Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Indian major carps
Chinese carps
Common carp
Tilapia
Pangasius *

* Over-winter fingerling production (Source: Case studies at the field level).

).

Siddique et al., 2025 [72] conducted a study to forecast air temperature and rainfall trends using Auto-Regressive Integrated Moving Average (ARIMA) modeling, to anticipate future trends to improve the planning and management of aquaculture. Time series data from 2011 to 2022 were obtained from NASA and validated against data from the Bangladesh Meteorological Department. The forecasts revealed a significant monthly increase in air temperature and a consistent decrease in rainfall, accompanied by distinct seasonal patterns. These trends suggest potential challenges for reproductive seasonality in Mymensingh. Moreover, they [73] applied the ARIMAX model to analyze the percentage weight gain of O. niloticus, revealing seasonal fluctuations influenced by water temperature and solar intensity. Over three years, forecasts showed a downward trend in percent weight gain during the first year, followed by an upward trend in the second and third years, highlighting the significant impact of seasonal changes. The simulated results were consistent with the forecasted trends, underscoring the importance of incorporating environmental factors in the management of reproductive seasonality for sustainable aquaculture practices. Pangasius farming, especially reliant on overwintered fingerlings raised from October to March (Table 4), has also been negatively impacted by warming trends, reducing survival rates and affecting reproductive seasonality [49]. Therefore, the aquaculture sector has to evaluate the potential changes in weather patterns that may impact the reproductive seasonality of the important cultured species. These measures should lead to a change in brood stock husbandry, hatchery, and grow-out production cycles for each of the major cultured species.

4.2.3. Impacts on Hatching and Larval Development

The larval and juvenile development, along with other biological processes of aquaculture species, are significantly influenced by various meteorological and water quality parameters [54]. Global climate change affects the fish growth, digestion physiology, and performance in marine and freshwater ecosystems [74]. Tilapia broodstock grow and reproduce best at water temperatures between 28 °C and 32 °C, which is the optimal range for reproductive performance [12].

Temperature considerably affects the hatching of eggs and the survival of larvae, as they are more susceptible to climatic changes than juveniles and adults, with temperature stress causing long-term effects throughout their life cycle [73,74]. A rise in water temperature to 30 to 33 °C significantly reduced the larval development process in tilapia [73]. Water temperatures exceeding 34 °C have been reported to cause serious physical deformities in tilapia larvae [42]. It has been demonstrated through research that water temperature control at embryonic and juvenile stages can lead to the induction of growth-stimulating genes and thus promote fish growth [75]. Recent studies indicate that water temperatures during summer in Bangladesh typically range from 30 °C to 40 °C [22]. The extreme temperature fluctuations between winter and summer remarkably impact hatchery activities, and a majority of hatcheries close during winter breeding months. This gap results in a shortage of seed production during the winter season, negatively affecting overall production [12].

The impacts of global climate change on aquaculture in Bangladesh demand urgent R&D to address emerging challenges in broodstock management, disease outbreaks, and seed production. Increased and fluctuating temperatures are causing physiological stress in fish, leading to a rise in pathogens such as viruses, bacteria, fungi, protozoa, and parasites, resulting in significant production and economic losses. However, the connection between climate variability and aquaculture diseases remains underexplored in Bangladesh. Research needs to focus on how changing rainfall and temperature patterns are disrupting natural breeding cycles and hatchery production, particularly for key species like Indian major carps, tilapia, and pangasius. Hatchery production, which depends on temperature-sensitive broodstock, is impacted by extreme heat, affecting brood performance, egg fertilization, larval survival, and growth rates [12]. Climate-resilient broodstock must be developed through R&D, enhanced hatchery practices for extreme weather, and optimized breeding cycles based on shifting seasonal patterns. Research on thermal-induced larval deaths, deformities, and the long-term impacts of thermal stress on fish reproduction and growth is crucial for guiding adaptive aquaculture practices. New technologies, such as controlled hatchery environments, thermally tolerant breeding strains, and early warning systems for disease outbreaks, could be vital for sustaining aquaculture performance. Given these challenges, a collaborative initiative encompassing fish health management, broodstock genetics, hatchery technology, and climate modeling is needed to ensure the resilience and sustainability of aquaculture amid ongoing climatic pressures.

4.3. Impacts on Coastal Aquaculture

Bangladesh’s coastal aquaculture, particularly shrimp (P. monodon) and integrated rice–freshwater prawn (M. rosenbergii) farming, is facing mounting pressure from a set of climate-related hazards. These include cyclones, tidal surges, floods, droughts, waterlogging, and coastal erosion, which cumulatively exert intense pressure on both production systems and livelihoods. Biswas et al., 2018 [76] found significant variations in economic losses from these events were observed, with losses in southern aquaculture areas reaching as high as USD 17.65 million, while the hilly region suffered negligible damage (<USD 0.05 million). This spatial variation mirrors the asymmetric vulnerability of aquaculture systems in ecological regions of Bangladesh.

Historical records highlight the significant impacts of climatic events over the years. Cyclone Sidr in 2007 resulted in the loss of lives and caused extensive damage to infrastructure, leading to a depletion of fish stocks and widespread water pollution, which in turn compromised household nutrition and income in the affected areas [13]. It is the consensus in the literature that climate change exacerbates the complexity of these risks. Coastal flooding not only results in physical damage to the pond but also introduces industrial pollutants, degrading water quality, reducing dissolved oxygen levels, and triggering disease outbreaks [77]. Studies by Maulu et al., 2021 [78] and Islam et al., 2017 [79] correlate these incidents to a series of climate-related stressors, including rising air temperatures, irregular weather, and high tidal waves. Furthermore, warming and acidification of the ocean are altering the marine chemistry of brackish water ponds and reducing the concentration of nutrients, impacting shrimp growth and increasing the prevalence of disease [80,81].

The empirical observations of farmers also corroborate these scientific results. Islam et al., 2019 [82] reported that 85.42% of shrimp farmers experienced temperature-related problems such as growth loss, disease outbreaks, and oxygen depletion. In the meantime, changes in the Bay of Bengal’s sea surface temperature have altered phytoplankton community structures toward harmful algal blooms, reservoirs of pathogenic bacteria, which are escalating public health and aquaculture risks [83]. Moreover, a 45 cm rise in sea level has been estimated to result in the loss of up to 75% of the Sundarbans shoreline by the end of the century, with a catastrophic effect on biodiversity and displacing fishermen [84]. Salinity intrusion and altered rainfall patterns are also disrupting freshwater flows, increasing soil salinity, and reducing photosynthetic activity in pond systems, ultimately lowering primary productivity and threatening system resilience [85,86].

Although the studies rely on post-disaster assessments or farmer surveys, long-term climate aquaculture interaction models remain scarce. This indicates a need for integrated vulnerability assessments and adaptive spatial planning to design resilient coastal aquaculture zones. The cumulative evidence makes it clear that without proactive adaptation strategies such as salinity-tolerant species, improved pond infrastructure, and ecosystem-based coastal protection, the coastal aquaculture sector of Bangladesh will face existential challenges in the coming decades.

5. Mitigation and Adaptation to Climate Change for Capture Fisheries and Aquaculture

5.1. Mitigation and Adaptation in Capture Fisheries

5.1.1. Identifying and Protecting the Valuable Areas

Bangladesh’s capture fisheries are highly vulnerable to climate change, necessitating urgent measures to enhance their resilience. Protecting ecologically valuable and climate-resilient areas is a critical strategy for maintaining fish stocks and ensuring the sustainability of fisheries under changing climate conditions. Several countries have successfully implemented similar strategies. This strategy has been successful in several nations worldwide. To conserve biodiversity and maintain fisheries in the face of climate-induced coral bleaching, Australia, for example, created Marine Protected Areas (MPAs), such as the Great Barrier Reef Marine Park [87]. According to Maliao et al., 2009 [88], community-based coastal resource management in the Philippines has made preserving important habitats like coral reefs and mangroves easier, increasing fishery productivity and climate change resilience. There is a lot of opportunity for climate adaptation and mitigation in Bangladesh if important ecosystems like the Sundarbans mangrove forest, the Meghna River’s Hilsa spawning and nursery grounds, and estuaries and coastal wetlands are preserved. These areas can be classified as co-managed MPAs and included in national spatial planning frameworks to improve ecosystem resilience and guarantee sustainable fishing yields. Moreover, it is crucial to identify and protect the natural habitats of inland and brackish waters capture fisheries, especially those that allow the survival of fish during dry seasons. These include rivers, canals, beels, estuaries, and haors. Such habitats as deep pools, for instance, are vital breeding habitats that sustain local and linked upstream-downstream fisheries and act as sanctuaries for fish when there is low flow in river systems like the Halda river. By declaring these breeding grounds as dedicated fish sanctuaries and enforcing appropriate environmental regulations, Bangladesh can promote ecosystem-based management and ensure the long-term sustainability of its fisheries.

5.1.2. Build Socioeconomic Resilience

Traditional fishermen in Bangladesh’s sea fisheries are highly vulnerable to unforeseen climatic occurrences such as cyclones, which cause enormous loss of human life and damage to livelihoods almost every year. The increased frequency and intensity of storms triggered by climate change underline the need for increased maritime safety. This can be achieved by investing in larger, more durable boats that are better equipped to handle harsh weather conditions than smaller boats. Apart from this, better mechanisms for early warning and prediction of extreme weather are needed to provide early warnings to fishing communities. Suitable onshore storage facilities for fishing gear and boats can prevent massive losses or destruction caused by cyclones and extreme weather conditions. Most of the small-scale fishers in Bangladesh are exposed to significant risks every time they venture into the sea because they lack safety-at-sea training and proper gear. These deficiencies greatly constrain their ability to develop climate variability and environmental change adaptability. Based on initiatives like Malaysia’s affordable insurance cover program by the National Fishermen’s Association [89] and India’s National Scheme of Welfare for Fishermen [90], Bangladesh could consider launching similar programs to provide social protection for its fishers. Furthermore, as experienced in Thailand [91], enhancing the adaptability capacity of fishers depends on factors like the availability of credit, social integration, equity, landholding, and substitute livelihoods such as tourism.

Given Bangladesh’s extensive network of rivers, estuaries, and coastal habitats, it is essential to enhance the socioeconomic adaptive capacity and resilience of fishers to address climate-related challenges, including salinity intrusion and extreme weather events [92,93]. Community-based management (CBM) has been effective in Bangladesh, where local people involved in fishing have strong, well-established traditional ecological knowledge. By combining this local knowledge with scientific inputs, CBM enhances adaptive capability, promotes sustainable resource management, and brings fisheries within equitable access to fisheries [94].

Furthermore, CBM fosters collective decision-making and local empowerment of fishing communities that reinforce compliance with conservation initiatives as well as social cohesion. In Bangladesh, where official governance institutions often have a poor ability to reach remote fishing communities, CBM serves as an important intermediary linking bottom-up stakeholders to policy guidelines. To build resilient fishing communities that will be able to withstand the diversified effects of climate change, institutional support for CBM needs to be increased, with enhancing capacity, collaborative connections between fishers, and strengthening NGOs and government agencies.

5.1.3. Implementation of Best Practices in Fisheries Management

Historically, fisheries with effective management practices have shown higher resilience to the impacts of climate change [95]. Free et al., 2020 [96] also showed that imperfect, but well-intentioned, management practices nonetheless enhance climate resilience in fisheries. These findings highlight that wider application of best management practices would go a great distance in mitigating most of the adverse effects of climate change on fisheries. In high-capacity fisheries systems, such best practices include scientifically established catch levels, robust accountability mechanisms, adaptive regional management, and protection of vulnerable fish habitats [97]. For example, in the United States, the implementation of such measures has resulted in dramatic reductions in overfishing, increases in fish biomass, and sustained catch levels, together with economic benefits [98]. Effective enforcement and rigorous constraints on fishing pressure are also potential components of effective fisheries management, in the interest of a precautionary principle in the face of climate uncertainty [99]. Altogether, these best practices result in ecological resilience via the maintenance of healthy stock, structurally diverse age structures, and genetic variability. They also foster socioeconomic resilience through providing fishers with a variety of choices and insulation against climate-induced losses in any one target species [96]. Translating these insights to Bangladesh is essential, as the nation depends heavily on fisheries for food security and livelihoods. Enhancing fisheries management through science-based governance, habitat conservation, and enforcement can build the resilience of Bangladesh’s fishing communities and aquatic ecosystems to growing climate hazards. The inclusion of adaptive management systems at local levels will be key to achieving the productivity and sustainability of Bangladesh’s fisheries sector in the face of a changing climate.

5.1.4. Nature-Based Adaptation Strategies

Nature-based climate change solutions have gained significant global momentum over the past few years, giving rise to a suite of composite concepts that encompass green infrastructure, ecosystem-based adaptation, working with nature, and ecosystem-based management [100,101]. In all but the most coastal nations, mangrove forests are being progressively valued and rehabilitated for their distinctive quality of protection against the impacts of climate-driven hazards while supporting livelihoods and biodiversity. Compared to conventional concrete barriers, mangroves are far more effective in wave energy dissipation, sediment trapping, shoreline erosion reduction, and stabilizing coastal areas [102,103]. Findings of the Kelty et al., 2022 [104] have demonstrated that healthy and dense mangrove forests can attenuate tsunami waves quite effectively. Mangroves are known to reduce wave height and slow storm surges as they move across the root systems, providing natural shoreline protection. For example, a study in Vietnamese mangrove belts recorded a 35% reduction in wave height across the first 80 m [105,106]. As a result, mangroves act as effective and inexpensive natural buffers against coastal inundation by regulating water flow and dissipating wave energy [85,106]. Globally, mangroves are recognized as highly efficient carbon sinks, with sequestration rates estimated to be 2–4 times higher than those of mature tropical or sub-tropical forests [107]. Donato et al., 2011 [108] reported that Indo-Pacific mangrove ecosystems store on average 1023 Mg C per hectare, with soils accounting for 49–98% of this carbon pool. Local studies further confirm the Sundarbans’ substantial carbon storage potential, with soil stocks in the top 1 m estimated at 212.21 tC/ha [109], and ecosystem-level stocks reaching 336.09 ± 14.74 Mg C ha⁻¹ in freshwater zones, with salinity shown to enhance belowground carbon proportions [110]. These findings underscore the Sundarbans’ role as a major blue carbon reservoir.

In Bangladesh, the Sundarbans, which are the largest mangrove forest in the Ganges-Brahmaputra-Meghna delta of the world, are central to addressing these climatic risks [46]. Growing emphasis is being placed on climate-resilient restoration initiatives such as community-based silviculture, bio-shield plantations, and shelterbelt creation to protect both the ecological integrity of the coastal belt [111] and could provide the livelihood security of the fishing communities. These initiatives are crucial components of a comprehensive climate resilience strategy for Bangladesh’s exposed coastline.

Bangladesh’s capture fisheries and coastal aquaculture are increasingly vulnerable to flooding, saltwater intrusion, and storm surges, all of which are projected to increase under future climate change. As many countries invest in mangrove restoration, Bangladesh can follow suit. By promoting large-scale mangrove rehabilitation, especially through community-based planting along shrimp gher bunds and integrating mangrove zones into coastal aquaculture planning, the country can enhance the resilience of fishers’ livelihoods while aligning with its national climate commitments. Leveraging international climate finance and incorporating co-management strategies with local stakeholders can ensure long-term stewardship and maximize both ecological and economic benefits. Thus, as the world increasingly turns to nature to combat climate threats, Bangladesh too can scale up mangrove-based adaptation as a cornerstone of sustainable fisheries and coastal protection.

5.1.5. Geospatial Issues to Deal with Climate Change

Bangladesh launched its first satellite into space in 2018, which has created numerous opportunities for leveraging geospatial data to enhance decision-making and resource management across the country. As a nation abundant in rivers and water bodies, Bangladesh requires careful monitoring and systematic utilization of these natural resources, particularly in the face of climate change. Geographic Information Systems (GIS) play a crucial role in identifying areas experiencing unusually high or irregular temperatures relative to the overall average. Beyond temperature monitoring, GIS provides powerful tools and frameworks for generating and applying precise geographic information [37]. It can provide visualizations of land-use patterns, water bodies, temperature variations, precipitation data, and topographical features, all of which are essential for effective resource management and climate adaptation strategies. Utilizing GIS technology, scientists in Bangladesh can effectively map and analyze the impacts of climate change on specific waterway regions. Sea surface temperature (SST), occurrences of El Niño, sea level, biomass, rainfall, surface wind, and sea surface height over the ocean geoid are controlling parameters of global climatic patterns [112]. RS and GIS were found to be effective tools by numerous research works to be applied for the analysis of such environmental attributes. Though the application of geospatial tools in fisheries-specific contexts is still underdeveloped, their potential for improving fisheries management and adaptation to climate change remains significant. The Centre for Environmental and Geographic Information Services (CEGIS), a government research center under the Ministry of Water Resources, specializes in resource management planning and environmental studies. CEGIS employs GIS and Remote Sensing (RS) for various applications, including water system development and environmental monitoring. The Bangladesh Space Research and Remote Sensing Organization (SPARRSO) is another key institution that utilizes satellite data to monitor agro-climatic conditions and water resources, which can support fisheries management. Bangladesh Agricultural University (BAU), through its Department of Aquaculture, incorporates GIS and RS in its research and educational programs, focusing on aquaculture planning and ecosystem studies. However, there is a limited focus on marine fisheries, and a significant gap exists in the capacity for applying GIS and RS specifically to this sector. In addition, there is a need for specialized training programs to build capacity in these technologies within Bangladesh’s fisheries and aquaculture sectors.

5.2. Mitigation and Adaptation in Aquaculture

The adverse impacts of climate change on fisheries and aquaculture can be more effectively addressed through the combined use of adaptation and mitigation strategies. To achieve sustainable and high-yield fish production with minimal environmental impact, resilience to the increasing intensity of climate-related issues must be developed. Climate-smart aquaculture (CSA) is a new approach seeking to enhance aquaculture systems’ resilience and sustainability in the context of climate change [113]. It involves technology and biological interventions, such as the development of climate-resilient fish species, using genomics and bioinformatics, and integrating the Internet of Things for the real-time monitoring of farms (Figure 5). Infrastructure modifications like flood-resistant pond designs and smart farming technologies (e.g., Recirculatory Aquaculture System -RAS) also contribute significantly (Figure 5).

CSA fosters the conservation of resources through water-saving systems, solar energy, and the recycling of wastewater. Moreover, it ensures food security by sustainable practices like alternative feed options and integrated multi-trophic aquaculture (IMTA). This assists in ensuring community-based aquaculture to enhance local food production and reduce the reliance on wild fish. Through the utilization of CSA, farmers could be able to manage environmental uncertainties while maintaining productivity as well as ecosystem integrity. It also enhances early warning systems and weather-based risk management. Climate-smart aquaculture subsequently contributes to a resilient, efficient, and inclusive blue economy.

5.2.1. Technological and Biological Intervention

Aquaculture, when integrated with agriculture, is a realistic approach to resource management that enhances the productivity of natural resources, enabling farmers to deal with the impacts of climate change, such as floods and droughts. It not only increases productivity and profitability but also promotes sustainability and offers diverse livelihood opportunities [114]. The practices are ranching, aquaculture, and integrated agriculture, IMTA systems, and an integrated floating cage aquaponics system (IFCAS) [115]. In IMTA, multiple species of different trophic levels are brought together in a synergistic system to facilitate the transfer of nutrients and energy among them through the water. Therefore, by-products like waste from one species are utilized as beneficial inputs (in the form of fertilizer or food) for other species within the system [116]. IMTA is also employed to help regulate water conditions, i.e., reducing salinity and increasing temperature, to enhance the growth of organisms such as mussels, shrimp, seaweed, and tilapia. In this system, seaweed and shellfish filter waste products naturally, preventing further mineralization and decreasing temperature increases caused by waste accumulation [117]. As primary producers, algae play a vital role in maintaining the ecological integrity of an ecosystem [118]. Adding algae to aquaculture systems has been shown to improve water quality and enhance productivity levels. Algae cultivation offers a sustainable method for lowering atmospheric CO₂ levels, serves as a renewable food source, and provides valuable compounds for use in biotechnology, aligning with several United Nations Sustainable Development Goals [119]. Effluents from aquaculture ponds can support crops during drought conditions, providing an alternative water source. At the same time, the nutrient-enriched waters can enhance crop productivity, and pond sediment can be utilized as a fertilizer when there is a shortage of conventional fertilizers [120]. Farmers would be able to utilize these salty tracts of land no longer suitable for crops to cultivate shrimp and other fish, such as tilapia, sea bass, and mullet, a practice already gaining popularity in coastal areas of Bangladesh [121]. The advent of the Internet of Things (IoT) could offer transformative opportunities for climate-resilient aquaculture. In the context of changing climatic conditions, IoT solutions have the potential to support real-time monitoring, data collection, analysis, and control of key environmental parameters [122]. This could enable aquaculture systems to adapt more effectively to fluctuations in temperature, salinity, dissolved oxygen, and other climate-sensitive factors, promoting more sustainable and responsive farming practices. Genomics and bioinformatics could play a crucial role in enhancing climate resilience in aquaculture by identifying stress-tolerant and disease-resistant fish strains. These tools enable deeper insights into gene-environment interactions, supporting selective breeding programs tailored to changing climatic conditions [123]. Through climate change, species diversification has been the principal method of adapting to its impacts by using air-breathing, salt-tolerant, and temperature-tolerant species. The utilization of catfish culture, which needs shallower ponds, provides a good remedy for the declining supply of water in inland saline environments [124]. Another alternative includes the production of plants and trees that require salt on the ponds’ dykes, generating income through their cultivation. Farming fish such as Clarias spp., Oreochromis spp., and P. sutchi for food output, along with sheltering fish with aquatic weeds in culture ponds to mitigate heat stress, offers viable strategies for enhancing aquaculture sustainability [124,125]. To enhance climate change-related stressors’ resilience, such as high temperatures, elevated salinity, and increasing disease outbreaks, selective breeding can be applied via the utilization of short life cycles in crops and fish species with high fecundity. Breeding technologies have been successful worldwide, such as hormonal sex reversal and production of genetically male tilapia, hormone-induced spawning in Pangasianodon, triploid oyster development, and selective breeding for disease resistance. Moreover, advances in genetic engineering have enabled the development of genetically modified (GM) feed ingredients, such as GM soy and rapeseed. These innovations hold the potential for creating genetically enhanced aquaculture species, such as tilapia, offering additional opportunities to strengthen aquaculture resilience in the face of changing environmental conditions.

5.2.2. Infrastructure Modification

Planned physical modifications within the area of aquaculture production systems can have enormous benefits, creating resilience and minimizing the harmful effects of climate-related stressors in coastal Bangladesh. Thermal stress may be successfully managed by surrounding culture ponds with shade-providing plants and trees, such as coconut trees and banana plants, as well as other local plants, to restrict direct sunlight and maintain water temperatures [126]. However, constructing higher and stronger dykes with sufficient height protects culture ponds from floods, tidal surges, and rough weather conditions that are common in the coastal belt of Bangladesh, including Jessore, Khulna, Satkhira, and Bagerhat districts.

Land elevation in pond areas makes such places suitable for integrated vegetable farming, which improves household nutrition and increases economic returns. In addition, safeguarding fences or enclosures constructed from bamboo with trap-door mechanisms can be tactically located close to homesteads or ponds to guard cultured fish against seasonal inundation, preventing losses due to monsoon flooding [127]. This integrated land-use system effectively maximizes the use of resources, is resilient to climate-induced vulnerability, and promotes sustainable livelihoods and food security in the coastal zones of Bangladesh. Beyond conventional adaptation practices, the recent literature also highlights geoengineering-based strategies that could offer long-term solutions to climate risks in coastal aquaculture and fisheries. Direct applications of geoengineering in Bangladesh’s aquaculture remain limited; insights from related fields suggest promising approaches. For instance, a multi-season field experiment using eight small reservoirs revealed 65–80% reduction in evaporation using floating disks and spheres [128]. At the landscape scale, modeling studies indicate that upstream freshwater flow, more than cyclonic surges, largely drives salinity intrusion in the GBM delta, supporting strategies such as river diversion and tidal river management to deliver sediment and freshwater inland [129,130]. Together, these findings suggest that both localized albedo (pond covers) enhancement and deltaic water-sediment engineering could be viable adaptation strategies, warranting targeted pilot projects and feasibility assessment.

5.2.3. Resource Conservation and Diversification

Water resources are gradually dwindling due to unpredictable rainfall patterns and a decrease in groundwater recharge. As most freshwater is utilized for irrigation, aquaculture progressively competes with agriculture, industry, and domestic sectors for a limited water supply. In Bangladesh, this problem is very critical in drought-prone regions, i.e., the Barind tract, and salinity-affected coastal regions, where freshwater supply is already under intense pressure. Furthermore, increased irrigation-based agriculture during the dry season reduces water availability for aquaculture operations. Sustainable practice in water use, including RAS, aquaponics, and IFCAS, is also receiving prominence as a promising solution to provide water-efficient aquaculture [54,120]. Among these, RAS offers a promising alternative by enabling high-density fish production in indoor tank-based systems with significantly low water consumption. RAS are designed to function with minimal water exchange, promoting environmental sustainability and efficient use of resources in aquaculture [131]. Mahalder et al., 2025 [54] utilized RAS for broodstock rearing, breeding, seed production, and larval rearing of H. fossilis, aiming to evaluate the overall suitability of RAS for seed production as an adaptation strategy in response to climate change. The implementation of RAS is expected to significantly contribute to climate-resilient aquaculture, offering a sustainable solution for fish seed production in Bangladesh. Moreover, Siddique et al., 2023 [132] conducted a study on the embryonic and larval development of O. niloticus, which is highly vulnerable to climate change. The research focused on assessing the development of Nile tilapia in both traditional hatcheries and RAS. This study was crucial for improving seed production for tilapia in RAS in Bangladesh.

Given the pressing challenges posed by water scarcity and environmental degradation, RAS offers not only a water-efficient solution but also plays a critical role in optimizing environmental sustainability, making it an ideal choice for aquaculture in Bangladesh and beyond. In addition to being environmentally friendly, water-efficient, and highly productive, intensive farming systems like RAS also help mitigate environmental degradation in Bangladesh [133]. They address issues such as habitat destruction, water pollution, depletion of biotic resources, loss of biodiversity, and the transmission of diseases and parasites [134]. RAS venture reuses water from culture tanks, reducing the requirement of water supplies from outside and enabling stringent regulation of the culture environment. It is versatile, which makes it possible the use RAS anywhere in the world, regardless of climate conditions [135], but farmers face several general constraints when adopting and operating RAS, including limited knowledge, inadequate training, and challenges with equipment and resources [132,135,136,137]. In Haryana, specific challenges reported by RAS farmers include disease outbreaks (50%), seed quality issues (45%), and a lack of understanding about RAS systems (35%). Additionally, 5% of farmers mentioned misguidance, while 10% faced difficulties in seed transportation. Approximately 70% of farmers emphasized the need for specialized training in RAS operations. Furthermore, 50% of farmers considered the lack of information about suitable fish species for RAS to be a major concern. Regarding RAS equipment, the most commonly malfunctioning components were drum filters (35%) and MBBR media (30%) [136]. In terms of aquaponics, there is a lack of comprehensive research to support the development of economically efficient aquaponic systems in Bangladesh. While several studies have explored various scientific aspects of aquaponics, there has been limited emphasis on its commercial implementation. Despite its potential as an effective and sustainable technology, aquaponics has not gained widespread popularity across Bangladesh [138].

Similarly, while aquaponics holds promise for sustainable farming, the adoption of alternative aquaculture systems like IFCAS faces its own set of challenges in Bangladesh. The initial investment required for setting up IFCAS is relatively high, posing a significant financial burden for poor farmers in Bangladesh [115]. One of the main constraints of IFCAS is its limited suitability for flood-prone areas, where fluctuating water levels and frequent inundation can damage the infrastructure and disrupt the system’s functionality. This makes it challenging for farmers in these regions to adopt IFCAS as a viable and sustainable aquaculture solution. However, despite the promising potential of RAS, Aquaponics, and IFCAS, there are currently no comprehensive estimates of the CO₂-eq avoided or sequestered through these systems in Bangladesh. This highlights an urgent need for further research to generate country-specific evidence, where standardized approaches such as IPCC Tier-1 emission factors could be applied to quantify mitigation benefits more accurately.

6. Conclusions and Recommendations

Fisheries and aquaculture in Bangladesh are central to national food security, employment, and economic growth but face mounting risks from climate change. The sector is increasingly exposed to habitat degradation, disrupted breeding and migration cycles, deteriorating water quality, and disease outbreaks, particularly in riverine and coastal ecosystems. Inland capture fisheries are affected by river siltation, reduced flows, and biodiversity loss, while aquaculture, especially hatchery-based and coastal systems, contend with temperature fluctuations, salinity variation, and extreme climatic events. Despite their critical role in the economy, research and policy responses to these threats remain limited. Addressing climate-driven vulnerabilities requires interdisciplinary strategies that integrate ecological restoration, technological innovation, and institutional reform. Investment in climate-resilient hatchery systems is essential, including broodstock management improvements and the introduction of thermally and salinity-tolerant species. Parallel efforts should prioritize rehabilitation of degraded river systems through re-excavation and restoration of aquatic connectivity to sustain migratory and native fish populations.

Technological adaptation is another pillar of resilience. Climate-smart aquaculture approaches such as RAS, IMTA, and the culture of tolerant species offer pathways to stabilize production under variable conditions. Early warning systems and real-time monitoring for floods, disease outbreaks, and water quality shifts can further mitigate risks from extreme weather events. To maximize impact, fisheries and aquaculture must be integrated into broader climate adaptation and food security policies. Such mainstreaming would enhance institutional coordination, resource mobilization, and inclusion of sectoral concerns in national planning. At the community level, adaptation should be supported through capacity-building, microinsurance schemes, and livelihood diversification for small-scale fishers and farmers. A major bottleneck remains inadequate funding for R&D, even though fisheries and aquaculture are the backbone of Bangladesh’s protein security. National institutions such as the Bangladesh Agricultural Research Council (BARC), Bangladesh Fisheries Research Institute, and Krishi Gobeshona Foundation (KGF) should strengthen support for thematic priorities under the Bangladesh Climate Change Strategy and Action Plan (BCCSAP). Finally, reinforcing the protection and restoration of coastal and wetland ecosystems, including mangroves and floodplains, is critical to buffering against salinity intrusion, sea-level rise, and biodiversity loss. Collectively, these interventions can enhance resilience, productivity, and sustainability, enabling the fisheries and aquaculture sector of Bangladesh to withstand the uncertainties of a changing climate.