Salinity is one of the most important abiotic factors affecting growth, metabolism, immunity and survival of aquatic species in farming environments. As a euryhaline species, the black tiger shrimp (Penaeus monodon) can tolerate a wide range of salinity levels and is farmed between brackish to marine water conditions. The current study tested the effects of six different salinity levels (0‰, 2.5‰, 5‰, 10‰, 20‰ and 30‰) on the selected physiological, biochemical and genetic markers (individual changes in the expression pattern of selected candidate genes) in the black tiger shrimp. Experimental salinity levels significantly affected growth and survival performance (p < 0.05); the highest levels of growth and survival performance were observed at the control (20‰) salinity. Salinity reductions significantly increased free fatty acid (FFA), but reduced free amino acid (FAA) levels. Lower salinity treatments (0–10‰) significantly reduced hemolymph osmolality levels while 30‰ significantly increased osmolality levels. The five different salinity treatments increased the expression of osmoregulatory and hemolymph regulatory genes by 1.2–8-fold. In contrast, 1.2–1.6-fold lower expression levels were observed at the five salinity treatments for growth (alpha amylase) and immunity (toll-like receptor) genes. O2 consumption, glucose and serotonin levels, and expression of osmoregulatory genes showed rapid increase initially with salinity change, followed by reducing trend and stable patterns from the 5th day to the end. Hemocyte counts, expression of growth and immunity related genes showed initial decreasing trends, followed by an increasing trend and finally stability from 20th day to the end. Results indicate the farming potential of P. monodon at low salinity environments (possibly at freshwater) by proper acclimation prior to stocking with minimal effects on production performance.

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A study was conducted to investigate fish species availability and socio-economic conditions offishermen of the Bergobindopur baor of Jashore district, Bangladesh. Data were collected from 30 fishermenof the baor through questionnaire interviews and focus group discussion. Various indigenous fish like rui,punti, tengra, shol, ayre, chital, mohashol and a few exotic fish like tilapia, silver carp, common carp, andgrass carp are available in Bergobindopur baor. Prices of fishes varied from species to species but high pricedfish were mohashol, chital, and shol. Kochal jal, net jal, and hela jal are used for fishing. A large portion offishermen (70%) were Hindu, almost all were male (96%) , married (91%) and middle aged (55%). Bothjoint and nuclear families were found among the fishermen. Yearly income of the maximum fishermen wasbetween Tk. 31000 and Tk. 50000. Non-constructed houses were more abundant (88%) and majority (61%)had electricity facilities. All fishermen used tube well water, sanitary latrines and took allopathic (80%)treatment which indicated positive signs for health condition. Through fishing, their socio-economic conditionhad improved. About 60% fishers had bank accounts and all sent their children to school as well as farmedcattle. However, the fishers faced some problems like lack of sufficient boats and gears, transportationproblems, inadequate training facilities, lack of financial supports, lack of awareness etc. Therefore, moreinstitutional, organizational, technical and credit supports are required to minimize their difficulties andensure their socio-economic betterment and sustainable livelihoods

Air pollution is causing a serious threat to public health in most of the urban centers of developing countries including Dhaka of Bangladesh, which is one of the most polluted cities in the present world. The road users in Dhaka city frequently complain about headache, eye and skin irritation and breathing problem. The research has find out that the situation is expected to be worsening further with the increase of population, economic development and high influx of people from rural areas to urbanized Dhaka. Motor vehicle is increasing at 5% per year in Dhaka, which is the most significant source of air pollution. The paper has analyzed the vehicular population structure and trends in Dhaka from 1990 to 2000 along with the role of different types of motor vehicle in this trends. The analysis show that 2-wheeler vehicle, car and taxi and 3-wheeler occupied 45, 22 and 12% respectively in 1992; while those were 38, 26 and 16% respectively in 2000. It is observed from the results that total NOX (Oxides of Nitrogen) emission in 2000 was 31903 tones and among them 3-wheeler vehicles, diesel trucks, and cars and taxis respectively contributed 44, 33 and 11%, while the total SOX (Oxides of Sulfur) emission was 19386 tones; and emitted by 58% and 17% from diesel truck, and car and taxi respectively. Finally, the research recommends several strategies for vehicular emission control with the aim of improving existing air quality in Dhaka.