Mostafa Ali Reza Hossain

Linking Human Nutrition and Fisheries: Incorporating Micronutrient-Dense, Small Indigenous Fish Species in Carp Polyculture Production in Bangladesh

Background Fish and fisheries are important for the livelihoods, food, and income of the rural population in Bangladesh. Increased rice production and changing agricultural patterns have resulted in a large decline in inland fisheries. Implementation of carp pond polyculture has been very successful, whereas little focus has been given to the commonly consumed small indigenous fish species, some of which are rich in vitamin A and minerals, such as calcium, iron, and zinc, and are an integral part of the rural diet. Objective The overall objective of the research and capacity-building activities described in this paper is to increase the production, accessibility, and intake of nutrient-dense small indigenous fish species, in particular mola (Amblypharyngodon mola), in order to combat micronutrient deficiencies. The large contribution from small indigenous fish species to recommended intakes of vitamin A and calcium and the perception that mola is good for or protects the eyes have been well documented. Methods An integrated approach was conducted jointly by Bangladeshi and Danish institutions, linking human nutrition and fisheries. Activities included food-consumption surveys, laboratory analyses of commonly consumed fish species, production trials of carp–mola pond polyculture, teaching, training, and dissemination of the results. Results No decline in carp production and thus in income was found with the inclusion of mola, and increased intake of mola has the potential to combat micronutrient deficiencies. Teaching and training of graduates and field staff have led to increased awareness of the role of small indigenous fish species for good nutrition and resulted in the promotion of carp–mola pond polyculture and research in small indigenous fish species. The decline in accessibility, increase in price, and decrease in intake of small indigenous fish species by the rural poor, as well as the increased intake of silver carp (Hypophthalmichthys molitrix), the most commonly cultured fish species, which is poor in micronutrients and not preferred for consumption, are being addressed, and some measures taken by inland fisheries management have been discussed. Conclusions The successful linking of human nutrition and fisheries to address micronutrient deficiencies has relevance for other countries with rich fisheries resources, such as Cambodia and countries in the Lake Victoria region of Africa.

Sperm cryopreservation of the critically endangered olive barb (Sarpunti) Puntius sarana (Hamilton, 1822)

The present study focused on development of a sperm cryopreservation protocol for the critically endangered olive barb Puntiussarana (Hamilton, 1822) collected from two stocks within Bangladesh and reared in the Fisheries Field Laboratory, Bangladesh Agricultural University (BAU). The sperm were collected in Alsevers solution prepared at 296mOsmol kg(-1). Sperm were activated with distilled water (24mOsmol kg(-1)) to characterize motility. Maximum motility (90%) was observed within 15s after activation, and sperm remained motile for 35s. Sperm activation was evaluated in different osmolalities and motility was completely inhibited when osmolality of the extender was ≥287mOsmol kg(-1). To evaluate cryoprotectant toxicity, sperm were equilibrated with 5%, 10% and 15% each of dimethyl sulfoxide (DMSO) and methanol. Sperm motility was noticeably reduced within 10min, when sperm were equilibrated with 15% DMSO, indicating acute toxicity to spermatozoa and therefore this concentration was excluded in further trials. Sperm were cryopreserved using DMSO at concentrations of 5% and 10% and methanol at 5%, 10% and 15%. The one-step freezing protocol (from 5°C to -80°C at 10°C/min) was carried out in a computer-controlled freezer (FREEZE CONTROL® CL-3300; Australia) and 0.25-ml straws containing spermatozoa were stored in liquid nitrogen for 7-15days at -196°C. The highest motility in thawed sperm 61±8% (mean±SD) was obtained with 10% DMSO. The fertilization and hatching rates were 70% and 37% for cryopreserved sperm, and 72% and 62% for fresh sperm. The protocol reported here can be useful for hatchery-scale production of olive barb. The use of cryopreserved sperm can facilitate hatchery operations, and can provide for long-term conservation of genetic resources to contribute in the recovery of critically endangered fish such as the olive barb.

Sperm cryopreservation of the Indian major carp, Labeo calbasu: Effects of cryoprotectants, cooling rates and thawing rates on egg fertilization

A sperm cryopreservation protocol for the Indian major carp, Labeo calbasu, was developed for long-term preservation and artificial fertilization. Milt collected from mature male fish were placed in Alsevers solution (296mOsmolkg(-1)) to immobilize the sperm. Cryoprotectant toxicity was evaluated by motility assessment with dimethyl sulfoxide (DMSO) and methanol at 5, 10 and 15% concentrations. DMSO was more toxic at higher concentrations than methanol, and consequently 15% DMSO was excluded from further study. A one-step cooling protocol (from 5 to 80°C) with two cooling rates (5 and 10°C/min) was carried out in a computer-controlled freezer (FREEZE CONTROL(®) CL-3300; Australia). Based on post-thaw motility, the 10°C/min cooling rate with either 10% DMSO or 10% methanol yielded significantly higher (P=0.011) post-thaw motility than the other rate and cryoprotectant concentrations. Sperm thawed at 40°C for 15s and fresh sperm were used to fertilize freshly collected L. calbasu eggs and significant differences were observed (P=0.001) in percent fertilization between cryopreserved and fresh sperm as well as among different sperm-to-egg ratios (P=0.001). The highest fertilization and hatching rates were observed for thawed sperm at a sperm-to-egg ratio of 4.1×10(5):1. The cryopreservation protocol developed can facilitate hatchery operations and long-term conservation of genetic resources of L. calbasu.

Bottleneck in the endangered kalibaus, Labeo calbasu (cyprinidae: cypriniformes) populations in Bangladesh revealed by microsatellite DNA marker analysis

Microsatellite DNA marker analysis was carried out to assess the population genetic structure of an endangered carp, Labeo calbasu, collected from three different stocks; the Jamuna River, the Halda River and a Hatchery. Four heterologous microsatellite loci (Lr12, Lr14b, Lr21 and Lr24) identified from rohu (Labeo rohita) were analyzed to test the genetic variability of the target kalibaus stocks. The maximum number of alleles observed in loci Lr12, Lr14b, Lr21 and Lr24 were 10, 7, 8 and 6, respectively. The loci were found to be polymorphic (<P95) in all the populations. The average number of allele was highest in the Jamuna population (6.75) followed by that of the Halda (5.50) and the Hatchery population (4.25). The observed average heterozygosity (Ho) value was almost similar in all three populations. Except locus Lr12 in the Halda population, significant deviations from the Hardy-Weinberg Equilibrium were detected in all cases due to excess heterozygosity. The population differentiation values (FST) between all the population pairs were significant. The highest genetic distance value (D = 0.295) was measured between the Halda and the Hatchery populations. A recent bottleneck was observed in the Halda and the Hatchery population.

Impacts and responses to environmental change in coastal livelihoods of south-west Bangladesh

Aquatic ecosystems are of global importance for maintaining high levels of biodiversity and ecosystem services, and for the number of livelihoods dependent on them. In Bangladesh, coastal and delta communities rely on these systems for a livelihood, and the sustainability of the productivity is seriously threatened by both climate change and unsustainable management. These multiple drivers of change shape the livelihood dependence and adaptation responses, where a better understanding is needed to achieve sustainable management in these systems, while maintaining and improving dependent livelihoods. This need has been addressed in this study in the region of Satkhira, in the southwest coast of Bangladesh, where livelihoods are highly dependent on aquatic systems for food supply and income. Traditional wild fish harvest in the rivers and aquaculture systems, including ghers, ponds, and crab points have been changing in terms of the uses and intensity of management, and suffering from climate change impacts as well. By means of six focus groups with 50 participants total, and validated by expert consultations, we conduct an analysis to understand the main perceived impacts from climate and human activities; and the adaptation responses from the aquatic system livelihoods. We find that biodiversity has decreased drastically, while farmed species have increased and shrimp gher farming turned more intensive becoming the main source of income. All these changes have important implications for food supply in the region and environmental sustainability. Dramatic responses taken in the communities include exit the fisheries and migration, and more adaptive responses include species diversification, crab fattening and working more on the pond and gher infrastructure. This study evidences the results of the combination of multiple stressors in productive systems and the barriers to adaptation in aquatic ecosystem dependent communities.

Labour, Identity and Wellbeing in Bangladesh’s Dried Fish Value Chains

Dried fish products play an important role in the diets of fish consumers and in the livelihoods of actors in fisheries value chains throughout Africa and Asia. In Bangladesh, a large proportion of marine and freshwater fish landings are processed by drying. The scale and significance of dried fish production, trade and consumption is rarely acknowledged and poorly understood, however, in part because of a tendency for fisheries research to focus on fishers, thereby overlooking actors and processes in mid- and downstream value chain segments. Adopting social wellbeing as an analytical framework, this chapter explores the material conditions faced by labourers engaged in drying fish in Bangladesh, and the ways in which their subjective experiences and objective circumstances are meditated by and constituted through a range of social relations. Case studies are presented from three field sites, where laborers with very different social origins are employed in fish drying under a diverse mix of relations of production, resulting in widely variable but frequently negative social wellbeing outcomes for the women and men involved. The case studies reveal how institutions and identities that constitute important components of social wellbeing for fishers may also be implicated in the exploitation of subordinate groups of labour.

Integrative Analysis Applying the Delta Dynamic Integrated Emulator Model in South-West Coastal Bangladesh

A flexible meta-model, the Delta Dynamic Integrated Emulator Model (ΔDIEM), is developed to capture the socio-biophysical system of coastal Bangladesh as simply and efficiently as possible. Operating at the local scale, calculations occur efficiently using a variety of methods, including linear statistical emulators, which capture the behaviour of more complex models, internal process-based models and statistical associations. All components are tightly coupled, tested and validated, and their behaviour is explored with sensitivity tests. Using input data, the integrated model approximates the spatial and temporal change in ecosystem services and a number of livelihood, well-being, poverty and health indicators of archetypal households. Through the use of climate, socio-economic and governance scenarios plausible trajectories and futures of coastal Bangladesh can be explored.

Livelihood Security: Implications from Aquaculture Sectors

Both aquaculture and fisheries have long been an integral part of life of the people of Bangladesh. The sector, second only to agriculture in the overall economy of Bangladesh, contribute nearly 4.5 % to the gross domestic product (GDP), 23 % of gross agriculture products and 2.46 % to the total export earnings. It accounts for about 60 % of animal protein intake in the diet of the people of Bangladesh with per capita fish consumption of 18.94 kg per annum. The people of Bangladesh largely depend on fish to meet their protein needs in both the rural and urban areas. In Bangladesh, to date about 20 finfish and a several crustacean species have been domesticated, their breeding and rearing protocols have been developed and now under nation-wide aquaculture. In addition to 1.32 million full time fishers, 14.7 million people have been involved in aquaculture in Bangladesh including fish farmers and prawn/shrimp farmers. The value chain from pond/farm to plate/fork and beyond the chain includes hundreds of stakeholders, whose livelihood fully depends on aquaculture. The major stakeholders include fish farmer, prawn/shrimp farmer, hatchery owner, nurserer, farm/hatchery technicians/workers, input (feed ingredient, fertilizer, hormone, chemical, instrument etc.) importers/suppliers, feed mill owners, homestead feed producer, fisher, fish processor, fish transporter, wholesaler, exporter, retailer, consumer, technology provider (government and non-government) and many more. Aquaculture has increasingly been playing a major role in total fish production (3.26 million tons) of the country and presently more than half of the total production (52.92 %) comes from aquaculture (1.73 million tons). The sector provides living and livelihood for more than 11 % people of the country. If the available resource are used sustainably with proper technological assistance, fish produced from aquaculture would efficiently meet the protein demand of growing population of the country, and will ensure, food and nutritional security, employment generation and foreign exchange earning leading to shaping a Bangladesh free of hunger, malnutrition and poverty.

Soil Health and Food Security: Perspective from Southwestern Coastal Region of Bangladesh

Bangladesh has a primarily agrarian economy. Agriculture is the single largest producing sector of the economy. Soil is the predominant aspect for a successful crop production; whereas, good soil health is a prerequisite for sustainable agriculture and food security. On the other hand, more than 30 % of the cultivable land in Bangladesh is in the coastal area. Out of 2.86 million hectares (ha) of coastal and off-shore lands about 1.056 million ha of arable lands are affected by varying degrees of salinity. Hence, this chapter would deal with status of soil parameters including soil salinity, its threat to sustainable crop production and food securities. Then the focus shifts to find out possible ways and few recommendations towards improving the soil health as well as reduction of the risk in southwestern coastal region of Bangladesh.

Water and sediment quality parameters in the Chalan Beel, the largest wetland of Bangladesh*

A study was conducted to investigate the status of the water and sediment quality in the Chalan Beel-a major fresh water fish reservoir of the country for a period of one year from July 2007 to June 2008. The mean values of water quality parameters (depth: 214.73±152.22 cm, temperature 27.68±4.26°C, transparency 123±82 cm, pH 9.7±0.47, total alkalinity 137±42 mg/L, conductivity 307±147 μs/cm, total dissolved solids 183±89 mg/L, ammonia-N 0.27±0.39 mg/L, nitrate-N 0.09±0.07 mg/L, phosphate-P 2.01±2.53 mg/L) and sediment quality parameters (pH 7.21±0.35, organic matter 2.59±0.52%, total nitrogen 0.09±0.04%, available phosphorus 5.4±3.6 Meq./100 g and exchangeable potassium 0.43±0.14 Meq./100 g) were within the range recommended for most of the inland fishes of Bangladesh. Although the water and sediment quality parameters except ammonia and phosphate are in the suitable range, the overall results suggest that better management techniques should be practiced in order to overcome the declining trend of associated aquatic life (fauna and flora) of this important fresh water body of Bangladesh.