Research Interests:
Research Interests:
Research Interests:
Research Interests:
Impacts of ineffective wastewater management on the biodiversity of receiving waters in developing countries are poorly documented. Using a before-after-control-impact methodology, we measured the effects of untreated wastewater release... more
Impacts of ineffective wastewater management on the biodiversity of receiving waters in developing countries are poorly documented. Using a before-after-control-impact methodology, we measured the effects of untreated wastewater release on the fish community in the Barnoi River, Bangladesh. In 2006, prior to untreated wastewater discharge, fish abundance, species richness and water quality were similar across sampling sites. In 2016, after 8 years of wastewater release to the downstream reach, fish abundance and species richness were reduced by>47% and>35% respectively at downstream sites compared to unaffected upstream sites and >51% and >41% lower respectively compared to the pre-wastewater discharge period. The wastewater impact was particularly severe during months of low discharge (October–December). Water transparency, dissolved oxygen and pH were lower (P< 0.001) at impacted downstream sites compared to upstream sites. Nineteen species (41.3% of all species we ...
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Research Interests:
The fish fauna of the Atrai River were studied for a period of two years from January 2011 to December 2012. Sampling was carried out by several fishing nets and traps on fortnight basis. A total of 74 fish species belonging to 27... more
The fish fauna of the Atrai River were studied for a period of two years from January 2011 to December 2012. Sampling was carried out by several fishing nets and traps on fortnight basis. A total of 74 fish species belonging to 27 families and 52 genera were recorded. Cyprinidae was the most dominant family contributing 18 species in 9 genera. Two alien species were found- Hypophthalmichthys molitrix and Hypostomus plecostomus. Thirty locally threatened species (Vulnerable 13.51%, Endangered 18.92% and Critically Endangered 8.11%) were recorded. But, no globally threatened species was found. Relative abundance of majority 36.49% species was rare. Global population trend of 24.32% recorded fish species was Declining. The highest number of species (42) was recorded in the November 2011. Whereas, the lowest the number of fish species (12) recorded in June and August 2011. Very high correlation was found between fish species and physical environmental parameters (air temperature, water ...
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Research Interests:
Research Interests:
This study was conducted in Narail district, Bangladesh between January and June, 2012; with a view to describing the status of rice- prawn-finfish based aquaculture practices. Average area of plots was 0.55±0.44 ha, of which mean ditch... more
This study was conducted in Narail district, Bangladesh between January and June, 2012; with a view to describing the status of rice- prawn-finfish based aquaculture practices. Average area of plots was 0.55±0.44 ha, of which mean ditch area was 4.35±2.02% of total land. All farmers dry their plots and made renovation prior to start of a new growing season followed by liming and fertilization. No standard stocking density was maintained, prawns were stocked at 15895 PL/ha, whereas fin fishes at 1551 seeds/ha. Commercial feed was applied in all the plots. Production of prawn, stocked and non-stocked finfishes were found 380.34±155.25 kg/ha; 713.65±352.99 kg/ha and 51.73±24.55 kg/ha respectively. Average cost and income for fish culture were 120514.07±36758.35 BDT/ha and 232497.48±76594.80 BDT/ha respectively. Average rice production was 4229.78±856.71 kg/ha. Low growth and high mortality of PL; scarcity, high and uprising price of feeds; and floods were identified as the major problems.
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This study described some biological parameters including lengths, length-length relationships and Fulton’s condition factors of Gagata cenia in the Padma River of Bangladesh, based on 1120 specimens collected from May to November, 2012.... more
This study described some biological parameters including lengths, length-length relationships and Fulton’s condition factors of Gagata cenia in the Padma River of Bangladesh, based on 1120 specimens collected from May to November, 2012. Maximum 39.78% female fishes were belonging to the length category of 55-60 mm whereas 51.06% male were belonging to 50-55 mm. The highest mean total lengths were found 66.51±10.28 mm (combined sex), 70.12±09.49 mm (female) and 61.08±09.45 mm (male) in the month of June. Similar findings are also presented for standard length, fork length, body depth, dorsal length, pectoral length, pelvic length and anal length. Linear relationships were also studied among mentioned lengths. Strong positive correlations were observed in all cases. Speraman’s Rank test indicated that there was a strong, positive correlation between total length and condition factor in female, which was statistically significant (rs=0.210, P=0.044). In male, there was no significant ...
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Different types of fishing methods and gears are being employed across the globe including Bangladesh. This study describes the underwater fishing method in the Padma River- one of the three largest rivers in Bangladesh. Standardised... more
Different types of fishing methods and gears are being employed across the globe including Bangladesh. This study describes the underwater fishing method in the Padma River- one of the three largest rivers in Bangladesh. Standardised efforts have been made for collecting data of interest between September 2016 and May 2017. Two types of underwater fishing, with or without using oxygen cylinders, were recorded. Mean duration of fishing per effort was higher (by 382%) when fishermen used oxygen cylinders. Mean water depth of fishing sites was also higher when oxygen cylinders were used. Three species of finfish ( Rita rita , Sperata seenghala and Labeo calbasu ) and one freshwater prawn species ( Macrobrachium dayanum ) have been identified in the catch. The catch was dominated by M. dayanum in both fishing types (27 ± 9.3 [with oxygen] and 15 ± 5.2 [without oxygen]). However, all the number of caught fish species varied significantly among different sampling months in both fishing me...
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Research Interests:
Microcrustacea in ephemeral wetlands produce dormant eggs to escape prolonged dry conditions. These eggs can hatch on inundation, although in most cases not all eggs hatch during a single wetting event. Incomplete hatching can reflect... more
Microcrustacea in ephemeral wetlands produce dormant eggs to escape prolonged dry conditions. These eggs can hatch on inundation, although in most cases not all eggs hatch during a single wetting event. Incomplete hatching can reflect bet-hedging strategies, but also the presence or absence of environmental cues that stimulate hatching. This study examines the effects of environmental cues likely to change for wetlands in the future, namely, temperature and water depth. Surface sediments collected from dry anabranches of the Macintyre River floodplain (eastern Australia) were inundated under two temperature regimes (warm and cool) in microcosms of two depths (shallow and deep). Hatched microcrustacea were sampled for 6 weeks. The abundance and assemblage composition of microcrustacea varied by temperature but not by depth. Although the total abundance was greater under warm conditions, the effect of temperature diminished over time. Temperature also had a greater effect on non-ostra...
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A variety of methods and gears are being employed across the globe including Bangladesh. This study describes the underwater fishing method in the Padma River- one of the three largest rivers in Bangladesh. Standardised efforts have been... more
A variety of methods and gears are being employed across the globe including Bangladesh. This study describes the underwater fishing method in the Padma River- one of the three largest rivers in Bangladesh. Standardised efforts have been made for collecting data of interest between September 2016 and May 2017. Two types of underwater fishing, with or without using oxygen cylinders, were recorded. Mean duration of fishing per effort was higher (by 382%) when fishermen used oxygen cylinders. Mean water depth of fishing sites was also higher when oxygen cylinders were used. Three species of finfish (Rita rita, Sperata seenghala and Labeo calbasu) and one freshwater prawn species (Macrobrachium dayanum) have been identified in the catch. The catch was dominated by M. dayanum in both fishing types (27 ± 9.3 [with oxygen] and 15 ± 5.2 [without oxygen]). However, all the number of caught fish species varied significantly among different sampling months in both fishing methods (P < 0.001...
Research Interests:
Impacts of ineffective wastewater management on the biodiversity of receiving waters in developing countries are poorly documented. Using a before-after-control-impact methodology, we measured the effects of untreated wastewater release... more
Impacts of ineffective wastewater management on the biodiversity of receiving waters in developing countries are poorly documented. Using a before-after-control-impact methodology, we measured the effects of untreated wastewater release on the fish community in the Barnoi River, Bangladesh. In 2006, prior to untreated wastewater discharge, fish abundance, species richness and water quality were similar across sampling sites. In 2016, after 8 years of wastewater release to the downstream reach, fish abundance and species richness were reduced by >47% and >35% respectively at downstream sites compared to unaffected upstream sites and >51% and >41% lower respectively compared to the pre-wastewater discharge period. The wastewater impact was particularly severe during months of low discharge (October–December). Water transparency, dissolved oxygen and pH were lower (P