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The generalized length-length relationships of Chanda nama ((Hamilton, 1822) belongs to Ambassidae were studied separately for a period of a calendar year collected from the Old Brahmaputra River, Mymensingh, Bangladesh for male, female and combined populations. A total of 1170 specimens were examined where 599 were male and 571 were female. The standard length, fork length and total length of male ranged from 19 to 79 mm, from 23 to 90 mm, and 28 to 100 mm respectively. The standard length, fork length and total length of female were found from 15 to 81 mm, 24 to 89 mm, and from 29 to 100 mm respectively. The generalized relationships of standard length and fork length, fork length and total length, and standard length and total length of male, female and combined populations were FL = 1.08 SL+1.41, TL = 1.11 FL + 1.54 and TL = 1.20 SL+2.81; FL = 1.09 SL+1.23, TL = 1.12 FL+1.04 and TL = 1.22 SL+2.22; and FL = 1.09 SL+1.20, TL = 1.11 FL+1.27 and TL = 1.22 SL+2.38 respectively. The coefficient of determination (R2) revealed high values in all regression analyses. In length–length relationships, the coefficient of determination (R2) ranged from 0.973-0.990. The present findings of this study will be helpful for a well-organized and significant exploitation and regulation of the Chanda nama fishery in the Old Brahmaputra River and surrounding ecosystems. Res. Agric., Livest. Fish.8(3): 339-347, December 2021

Growth pattern of pama croaker Otolithoides pama population in the Bay of Bengal was determinedas the corollary of relationships between standard length (SL) and total length (TL), the two most prevalentlyused linear dimensions of fin fish species. Monthly pama croaker samples were collected from the industrialfisheries in the Bay of Bengal. The length-length relationship was constructed algebraically in the form ofy=a+bx. Relationships between SL and TL for male, female and unsexed populations were separatelyestablished. Sex ratio between male and female did not deviate from the parity (?2 test; p>0.05). The SL andTL ranges of male were 7.2-22 cm and 9.5-28 cm respectively, and the SL and TL ranges of female were6.8-20 cm and 8.4-25.7 cm respectively. Intercept and slope varied monthly in all length-length relationshipsregardless of gender categories. The generalized SL-TL relationships of male, female and unsexedpopulations were TL=1.214SL+0.761(R=0.989), TL=1.212SL-0.770(R=0.990) and TL=1.203SL+0.904(R=0.987) respectively. The correlation coefficients of both monthly and generalized regression analyses ofall sex types were very high (R?0.852) which explained that the relationships between the two lengthdimensions were strongly correlated. The growth corollary appeared both as isometric and allometric formonthly populations. Allometric growth was apparent in July, August and September in all gender types,while isometric growth was deduced in other months. This study would be useful for future research in orderto make comparisons with the relevant aspects of O. pama population between years and locations in the Bayof Bengal.

The intercept as the coefficient of algebraic relationship between standard length (SL) and total length (TL), the two predominantly used linear dimensions of fin fish species, was referred to growth pattern deduction for rainbow sardine Dussumieriaacuta population in the Bay of Bengal. Monthly rainbow sardine samples were collected from the industrial fishing vessel in the Bay of Bengal over a period of a calendar year. The length-length relationship was formed algebraically as y=a+ bx. Linear relationship between SL and TL for male, female and unsexed populations was constructed separately. Chi-squared test affirmed that sex ratio between male and female did not deviate from the parity (P>0.05). The SL and TL ranges of male were 13.1-16.8and 16.4-20.7 cm respectively, they for female were13.4-17.2 and 16.5-20.9 cm respectively. Slope and intercept showed variation monthly in all length-length relationships regardless of sexes. The generalized SL-TL relationships of male, female and unsexed populations employing pooled data over the study period were TL=1.130SL+1.571 (R=0.908), TL=1.106SL+1.925 (R=0.911), and TL=1.114SL+1.825 (R=0.908) respectively. The correlation coefficients of all monthly and generalized regression analyses of all sex categories were very high (R≥0.786), a fact that explained the associations between two length dimensions were strongly related. Study revealed isometric growth for male in all months, while algometry was apparent for female and unsexed populations in a few months. Present findings of length-length relationship and growth pattern for D. acuta population in the Bay of Bengal would remain useful for future references. Res. Agric., Livest. Fish.7(3): 545-551, December 2020

Heavy metal pollution due to anthropogenic activities poses a great threat to aquatic organisms. The present study was conducted to evaluate the cytotoxic and genotoxic effects of hexavalent chromium (potassium dichromate) on hemato-biochemical, histo-pathological, and genetical changes in striped catfish Pangasianodon hypophthalmus. Three sub-lethal doses (0.8, 1.6, and 3.2 mg/L) of chromium (Cr) were selected and fish were exposed in vivo contrasting with a control (0 mg/L) for 30 days. The study revealed that various hemato-biochemical parameters showed a significant decrease in hemoglobin (Hb), red blood cells (RBCs), and blood glucose content, whereas white blood cells (WBCs) significantly increased in Cr exposed fish. Frequencies of all forms of structural abnormalities of erythrocytes (erythrocytic cellular abnormalities; ECA, erythrocytic nuclear abnormalities; ENA and erythroblasts; Ebs) were significantly increased in higher two test concentrations (1.6 and 3.2 mg/L) when compared to control. Differential leucocyte count exhibited significant increase in neutrophil and decrease in lymphocytes in the highest Cr treated group. The severity of various histo-pathological changes in the gills, liver, and kidney were increased considerably with the increase of Cr concentrations. Similarly, the amount of DNA (ng/μl) decreased significantly in blood and tissues of different vital organs where the liver showed the highest decline compared to control in a concentration-dependent manner. Taken altogether, P. hypophthalmus is susceptible to Cr and can be used as a bio-indicator to assess aquatic metal pollution.

Shrimp has become one of the most important export products in recent decades due toincreasing international demand. Shrimp farming is performing significant role in thelivelihoods of rural people of southwestern part of Bangladesh which is considered thecore areas for shrimp farming. To continue the trend of exporting shrimp worldwide it isvery much needed to be familiar with the current culture practices with the precautionstaken by the shrimp farmers. A total of 30 shrimp farmers in Shyamnagarupazilla ofSatkhira district were interviewed to understand the present status of shrimp farming alongwith to identify the problems faced by the farmers, and to formulate somerecommendations for better shrimp production development. Study showed thatpolyculture was the only culture technique followed by the shrimp farmers using naturalwater sources like rain and tide. Bagda (Penaeusmondon) was the dominant culturedspecies followed by Harina (Metapenaeusmonoceros) because of their economicsignificance. Although wild post-larvae (PL) are better in quality than hatchery producedPL, farmers collected PL from both sources. Farmers usually used inorganic fertilizers likeUrea and TSP instead of organic one, but they preferred natural feeds for cost efficiencyand management purposes. The study also identified that shrimp diseases (white spot, gillrot and fin rot), lower market price, flood, high mortality and lack of scientific knowledgewere the major constraints in shrimp farming. Government, donor agencies, planners,researchers and NGOs, therefore, should come forward to assist farmers for mitigatingproblems and achieve sustainable shrimp export earnings of Bangladesh. Res. Agric., Livest. Fish.7(2): 311-320, August 2020

The present study was conducted to investigate the growth parameters, length-weight relationshipand diverse mortality rates of Bombay duck Harpadon nehereus, from North-eastern tip of the Bay of Bengal.The length weight data were collected from January to December 2017 where a total number of 2054individuals of both sex were analyzed. The von Bertalanffy growth parameters, the asymptotic length L?(cm), the growth constant K (year-1) and t0 were estimated as 38.50, 0.88, and -0.0181 years respectively.The growth performance index (Ø?) was found to be 3.115. The total length and body weight (L-W)relationship was found as W=0.004 L3.021, indicating that the growth rate showed a positive allometricpattern (b=3.021>3). The annual fishing morality rate (F) was 1.89, whereas the natural mortality rate (M)was 1.51. The obtained value of the exploitation rate (E= 0.56) indicated that the said population was inover-exploited condition.

In Bangladesh, aquaculture has expanded, diversified, intensified and technologicallyadvanced due to the decline in fish production from the open water natural sources. Quality seedsare prime requirements for aquaculture production. Quality of seeds depends on the quality ofbroods used for spawning. Breeding performance depends on the quality of feeds and feedingmanagement during brood stock rearing. The present study focused on the evaluation of qualityof feed used in the fish farms, the performance of brood stock and fingerlings of selected carp,catfish and perch farmed in Bangladesh through a survey. On the basis of top fish productiondistricts, we divided the whole country into four hubs, such as Mymensingh, Jashore, Cumillaand Rajshahi. Data were collected from 300 individual respondents of commercial fish farms, 75from each hub. It has been found that most of the farm owners (91%) used commercial feedinstead of homemade feed, though a considerable number of respondents replied that quality ofhomemade feed was better than commercial feed. Although most of the farm owners collect fryfrom private/own hatcheries (69%), a considerable number of grow out farms owners replied thatthe fry of government hatcheries/brood bank, river and BFRI were better than private hatcheriesin terms of growth performance, disease resistance and survivability. Therefore, for sustainableaquaculture, farm owners should be careful for the selection of feed, brood and fingerling.

Leaf blade of Saccharum spontaneum L. was scrutinized microscopically in the present study. Surface features and internal structures in leaf blades from plants grown in natural terrain were examined in peelings and transverse sections after staining with 1% aqueous solution of safranin. Different types of cell diagram were measured from the photographs. In both abaxial and adxial surfaces of the leaf blade, stomata, cork cells, micro hairs, long and short cells with sinuous wall were recognized. Epidermal cells (15.13µm) were found compactly arranged with oval shaped cells. Mesophyll layer composed of chlorophyllus cells, were 31.04 µm in diameter with irregular intercellular space and in between large air spaces were attended. Mesophyll cells surrounded chlorophyllus bundle sheath (14.17 µm in diameter) in a ring like fashion. The distance between vascular bundles were met up by two mesophyll cells, suggesting C4 plant characteristics. Sclerenchymatous cells (12.71 µm) were recorded excessive in the region of large vascular bundle. In vascular bundle, phloem set with sieve tube and companion cell elements and xylem is composed of vessel, fibers and xylem parenchyma. A fiber cell was measured 10.58 µm in average diameter. The group vessel was observed, will be an identical feature for this grass studied. Lysigenous cavity in protoxylem region of large vascular bundle was a notable feature for this grass. The absence of thickened wall mestome sheath around vascular bundle and exclusive presence of bundle sheath cells layer, are the features of NADP-ME subtype C4. The results of the present study are specifying that the experimented plant S. spontaneum is a NADP-ME subtype C4 grass. The anatomical features of the grass studied here will help to resolve taxonomic problems of the Gramineae family., {"references":["Ahmad, F., Khan, M. A., Ahmad, M., Zafar, M., Arshad, M., Khan, A., Shah, G. M., & Awan, M. R. (2010). Taxonomic utilization of anatomical characters in tribe Andropogoneae (Poaceae) based on transverse sections of leaves. Journal of Medicinal Plants Research, 4(14), 1349-1358","Ahmad, F., Khan, M. A., Ahmad, M., Zafar, M., Iqbal, Z., & Khan, A. (2011). Leaf epidermal anatomy as an aid to the identification of genus Setaria weeds, tribe paniceae (Poaceae), from the salt range of Pakistan. Journal of Medicinal Plants Research, 5(15), 3500-3506.","Al-Janabi, S. M., Honeycutt, R. J., McClelland, M., & Sobral, B. W. (1993). A genetic linkage map of Saccharum spontaneum L. 'SES 208'. Genetics, 134(4), 1249-1260.","Sultana, R. S., & Rahman, M. M. (2020). Anatomy of Phyllanthus niruri L. (Euphorbiaceae). EBAUB J., 2, 24-29.","Rahman, M. M., & Sultana R. S. (2021). Anatomy on leaf blade of Eleusine indica L. (Gramineae): a Study on kranz grass. EBAUB J., 3, 1-8.","Rahman, M. M., & Sultana, R. S. (2020). Anatomy and developmental changes in stem of Leucas aspera (Wild.) Link. (Lamiaceae). EBAUB J., 2, 1-8","Rahman, M. M., & Sultana R. S. (2019). Stem, leaf and root anatomy of Eclipta alba (L.) Hassk. (Asteraceae). EBAUB J., 1, 1-7"]}

Biological features including sex ratio, length-frequency distributions (LFDs), size at sexual maturity, spawning season, length-weight relationships (LWRs) and condition factor of Chanda nama were studied in the Old Brahmaputra River, Bangladesh. There was no significant difference in sex ratio. LFDs indicated no significant differences in size between the sexes. Size at sexual maturity was estimated at ~3.0 cm standard length. Monthly variations in gonadosomatic index indicate that the main spawning season is from July to August. The LWRs showed isometric growth in males and positive allometric growth in females. Fulton’s condition factor varied in both sexes and was attributed to variations in GSI with maturity. The findings of this study will be helpful to formulate conservation and management strategies of C. nama population in the Old Brahmaputra River and surrounding ecosystems.

Heavy metal pollution due to anthropogenic activities poses a great threat to aquatic organisms. The present study was conducted to evaluate the cytotoxic and genotoxic effects of hexavalent chromium (potassium dichromate) on hemato-biochemical, histo-pathological, and genetical changes in striped catfish Pangasianodon hypophthalmus. Three sub-lethal doses (0.8, 1.6, and 3.2 mg/L) of chromium (Cr) were selected and fish were exposed in vivo contrasting with a control (0 mg/L) for 30 days. The study revealed that various hemato-biochemical parameters showed a significant decrease in hemoglobin (Hb), red blood cells (RBCs), and blood glucose content, whereas white blood cells (WBCs) significantly increased in Cr exposed fish. Frequencies of all forms of structural abnormalities of erythrocytes (erythrocytic cellular abnormalities; ECA, erythrocytic nuclear abnormalities; ENA and erythroblasts; Ebs) were significantly increased in higher two test concentrations (1.6 and 3.2 mg/L) when compared to control. Differential leucocyte count exhibited significant increase in neutrophil and decrease in lymphocytes in the highest Cr treated group. The severity of various histo-pathological changes in the gills, liver, and kidney were increased considerably with the increase of Cr concentrations. Similarly, the amount of DNA (ng/μl) decreased significantly in blood and tissues of different vital organs where the liver showed the highest decline compared to control in a concentration-dependent manner. Taken altogether, P. hypophthalmus is susceptible to Cr and can be used as a bio-indicator to assess aquatic metal pollution.

One of the most important blossom trades in the economy of Bangladesh is fish marketing. To understand the current practices of fish market and marketing systems in Bogura district of Bangladesh, an investigation was conducted based on existing marketing system and economic features of marketing activities and inefficiencies. Fish marketing is almost exclusively maintained by the private sector and large number of intermediaries such as local traders, agents/suppliers, and retailers are involved in the distribution process of fish marketing. Data were collected from 45 fish traders through questionnaire interviews and participatory rural approach methods during December 2011 to May 2012 from three different fish markets named as Fateh Ali Fish Market, Godarpara Fish market and Khandar Fish market of Bogura district. The daily supply of fish in Fateh Ali Fish market, Godarpara Fish market and Khandar Fish market were estimated at 6.75 tons, 0.765 tons and 0.495 tons, respectively. Present supply and requirement of the fish showed a wide gap and virtually most of the fish (85%) is imported from outside where the local supply of fish is only 15%. There is a high consumer preference for Indian major carps i.e. rohu, catal, mrigal and exotic carps silver carp, grass and common carp, tilapia, pangas etc. The price of fish depends on market structure, species, quality, size, weight and season that’s why a well-systematized marketing setup is crucial for reasonable price for fishes. The study revealed that almost all traders in three markets made a considerable amount of profit and broadly improved their food consumption facilities, standards of living, purchasing power, choice and ability as an economic sector. However concerns arise about the sustainable marketing system due to higher transport costs, poor transport facilities, inadequate supply of ice, lack of money for business, and poor institutional support. It is an urgent issue to establish ice factory, improvement of transport facilities, provision of governmental, institutional and banking assistance, introduction of fish quality control measures and training of fish market operators for improved their marketing system. Therefore, the present study emphasizes the fundamental marketing system, market flow of fish, availability of fish in these three markets, and market related constraints in Bogura district, Bangladesh. Res. Agric., Livest. Fish.5(3): 399-410, December 2018

The neonicotinoid insecticide imidacloprid is used in Bangladesh for a variety of crop protection purposes. Imidacloprid may contaminate aquatic ecosystems via spray drift, surface runoff and ground water leaching. The present study aimed at assessing the fate and effects of imidacloprid on structural (phytoplankton, zooplankton, macroinvertebrates and periphyton) and functional (organic matter decomposition) endpoints of freshwater, sub-tropical ecosystems in Bangladesh. Imidacloprid was applied weekly to 16 freshwater microcosms (PVC tanks containing 400 L de-chlorinated tap water) at nominal concentrations of 0, 30, 300, 3000 ng/L over a period of 4 weeks. Results indicated that imidacloprid concentrations from the microcosm water column declined rapidly. Univariate and multivariate analysis showed significant effects of imidacloprid on the zooplankton and macroinvertebrate community, some individual phytoplankton taxa, and water quality variables (i.e. DO, alkalinity, ammonia and nitrate), with Cloeon sp., Diaptomus sp. and Keratella sp. being the most affected species, i.e. showing lower abundance values in all treatments compared to the control. The observed high sensitivity of Cloeon sp. and Diaptomus sp. was confirmed by the results of single species tests. No significant effects were observed on the species composition of the phytoplankton, periphyton biomass and organic matter decomposition for any of the sampling days. Our study indicates that (sub-)tropical aquatic ecosystems can be much more sensitive to imidacloprid compared to temperate ones.

Community Based Fisheries Management (CBFM) approach appears to be an important factor in managing fisheries successfully. Thus, this study aims to investigate and evaluate the fisheries management practices and its impact on the livelihood of the fisheries community of Sherudanga beel in Rangpur district (Bangladesh) for a period of 12 months, from March 2010 to February 2011. The study was conducted based on Community Based Fisheries Management (CBFM) practices, beel biodiversity, fish production, socio-economic and livelihood condition of the fishermen community. The studied beel is 83 acre seasonal floodplain, which was mainly used by a community consisting of 80 families for their livelihood, where the CBFM approach was introduced by the community. At pre-CBFM, there was no controlled management system from any NGO or even Government for the proper management of the beel. Recently, community fishers leased out this beel from the government in year 2000 for 12 years and started to manage it. The CBFM project works for the development of fishery system, the fishermen community and the general society. The yearly gross fish production was higher than pre-CBFM period, implying that average abundance and fish biodiversity were significantly higher in the CBFM implemented beel. Majority of the fishermen had primary level education (37.5%) compared to 27.5% and 16.5% having secondary level and above secondary level education respectively, while 18.75% of them could sign their name only, indicating the improvement of education level among fishers. About 43.75% of them had small size family, while 40.0% and 16.25% had middle and large size families respectively. The prevalence of unconstructed house was the highest (77.5%) while few of them (22.5%) had semi constructed house. About 68.75% of the fishermen had medium income, while 12.5% and 18.75% had small and large income respectively. More than half (56.25%) of the fishermen received credits from different sources while rest (43.75%) of them did not get any credits. In conclusion, the overall findings showed that community based fisheries management has significantly increased annual fish production, lifted household income levels, improved access to credit from a wide range of sources and enabled livelihood diversification.

Potentials and prospects of pond fish farming in improving aquaculture system in Kaliakair upazila under Gazipur district, Bangladesh were investigated. Data were collected from 60 selected fish farmers through questionnaire survey and Focus Group Discussion (FGD) during June to November, 2014. The research revealed that a highest number of pond fish farmers (61.67%) were out of training facilities and a good portion (23.33%) had no education. Pond water was found turbid seasonally (71.66%) and farmers did not exchange water during culture periods (66.67%). As a result water quality deteriorates day by day and depletion of oxygen occurs during pond farming. The average stocking density of fish was higher in the study area and the highest was found in monoculture of Climbing perch (Anabas testudineus ) (1200 individual/decimal) and lowest in carp polyculture system (195 individual/decimal). Fish production was higher in Pangus monoculture system (17.89 MT/ha/yr) and lower in Climbing perch monoculture system (10.78 MT/ha/yr), but profit was higher in Climbing perch monoculture produced 1318100 Tk./ha/yr and lower in Tilapia monoculture 397886 Tk./ha/yr. Benefit Cost Ratio was higher in Climbing perch (2.32) and lower in Pangus culture (1.34). The problems faced by the fish farmers were broadly categorized as financial, natural, technical and social. Therefore, necessary training facilities with institutional and organizational supports, credit facilities, extension services and awareness development are essential to improve aquaculture system as well as the fishers’ livelihoods in Kaliakair upazila of Gazipur district.Res. Agric., Livest. Fish.2(3): 517-528, December 2015

Blue Stripped hermit crab, Clibanarius longitarsus (De Haan, 1849) was collected from Kalagachhia, Satkhira Forest Range of Sundarban Mangrove Forest on 18 April 2015 during an exploration of the IUCN Crustacean Exploration Team. This crustacen decapod was recorded for the first time from Bangladesh geographical area.Bangladesh J. Zool. 43(1): 131-135, 2015

Aim: The rising cases of dental problems among diabetic patients have raised health concerns among dentists worldwide. The oral complications of prime concern are gum disease, dental caries, dry mouth, oral soft tissue damage, and pain in the face and mouth. This descriptive type of cross sectional study was conducted among the diabetic patients for their management of dental problems attending in selected dental clinic in Dhaka city from January to June 2012. 44% of the patients were in between 41to 50 years age group.Methods: Data were collected with a pretested semi structured questionnaire and check list was filled in after oral examination.Results: Among the patients 84% were Muslims and 16%. were Hindu. All the patients were married. 58% of the patients had monthly income TK. 25000-40000. Among the patients, 48% had (4-5) family members. Type of family was single for 82% of the patients. Main food was rice for 78% of the patients. 50% of the patients had habit of tobacco use. Tobacco smokers were 88%. Among the patients, calculus and gingivitis was in grade I for 54% and the condition of periodontitis was in grade I for 46%. The condition of oral thrush was in 0 grade for 66% of the patients. Most of the patients’ 1 tooth was affected by dental caries. There was no dry mouth in 80% of the patients, whereas no burning mouth syndrome was in 82% of the patients; 64% of the respondents visited dentists. The reason for visiting dentists, most of them visited for sensitivity. All the patients brushed teeth everyday. 66% of the patients brushed teeth once a day. Among the patients 66% cleaned teeth before breakfast and 52% took 3-4 minutes. Among the patients, 90% used tooth brush and 88% used tooth paste for cleaning the teeth. 84% of them did not floss and the rest 62.5% flossed teeth once a day, 62% got information about type of diabetes, among them 62.5% informed about non insulin dependent type of diabetes. Among the patients, 60% got information about usual oral hygiene, 75.9% got information about usual oral hygiene from doctors.Conclusion: Proper patient management requires close interaction between the dentist and the physician. Working with diabetic patients can be challenging and rewarding when open communications are established and thorough patient education is attained.Bangladesh Journal of Dental Research and Education Vol.5(2) 2015: 55-58

Histopathological study was carried out with the gills of female striped gourami ( Trichogaster fasciata ) exposed to chlorpyrifos 20 EC. The main objective of the present work was to evaluate the effects of chlorpyrifos to observe the histopathological alterations on gills of striped gourami caused by chlorpyrifos toxicity. To conduct the experiment, 15 PVC tanks each containing 300 L water were used. Female fishes were kept in 15 tanks and conditioned for 21 days prior to chlorpyrifos exposure. Five sub-lethal concentrations (0, 15, 50, 150 and 500 μg/L) of chlorpyrifos based on previously estimated LC 50 of 880 μg/L were used in this study for 75 days. There were significant changes on gills until 75 days. A number of changes such as hemorrhage, hypertrophy, necrosis, pyknosis, vacuums, splitted gill lamellae and missing of gill lamellae were observed in the gills of striped gourami exposed to chlorpyrifos in T 15 , T 50 and T 150 µg/L concentrations. There were notable histopathological changes in T 15 , T 50 and T 150 µg/L concentrations in comparison with control group. All the fishes died within 75 days when exposed to 500 µg/L concentration of chlorpyrifos. This investigation sufficiently revealed that chlorpyrifos had adverse effects on the gills of investigated fish. The present research suggested that the use of chlorpyrifos in agriculture should be carried out with a great caution.

The length-weight relationships (LWRs) of Macrobrachium lamarrei (H. Milne-Edwards, 1837) was studied to construct the generalized relationships of body weight to carapace length measurements for male, female and combined prawn population separately over a calendar year. A total of 1018 specimens were used for this study. The parameter values of the equation W = a L b describing the relationships between body weight and carapace length for male, female and combined prawns. The parameter of equations, a varied from 0.00096 to 0.00333, 0.00059 to 0.00728 and 0.00081 to 0.00440 for male, female and combined prawn population respectively. On the other hand, the slope of equations, b varied from 2.4363 to 2.8229, 2.0761 to 3.0314 and 2.2915 to 2.8998 for male, female and combined prawn population respectively indicating isometric growth in females but negative allometric for males suggesting that female prawns were comparatively in better condition than males of the same population. The generalized length-weight relationship was fitted with the pooled data of all monthly samples for male, female and combined prawn separately which were BW = 0.0008 CL 2.924 , BW = 0.0012 CL 2.783 and BW = 0.0010CL 2.845 respectively indicating negative allometric growth as b varied from 2.783 to 2.924. The results further revealed that all length-weight relationships (LWRs) were highly correlated (r 2 > 0.904). DOI: http://dx.doi.org/10.3329/ralf.v1i1.22377 Res. Agric., Livest. Fish. 1 (1): 137-145, Dec 2014

The effects of periphyton grown on bamboo substrate, on growth and production of Nile tilapia, Oreochromis niloticus (Genetically Improved Farmed Tilapia strain) in monoculture and polyculture with the freshwater prawn (Macrobrachium rosenbergii) were studied and economically evaluated. The experiment had 2 × 2 factorial design: The first factor was presence or absence of substrate for periphyton development, the second factor was related to culture system. The first system was monoculture of the GIFT strain of Nile tilapia stocked at 20,000 fingerlings ha¿ 1, the second system was tilapia¿prawn polyculture with each stocked at 20,000 fingerlings or postlarvae ha¿ 1. Bamboo poles were posted vertically in ponds under substrate treatments. Feed and inorganic fertilizers were applied to all ponds. There were no differences in phytoplankton biomass and primary productivity between the treatments (P > 0.05). The electivity indices indicated that there were low dietary overlaps between tilapia and prawn. Survivals of tilapia and prawn were higher in ponds with bamboo substrate (60% and 35%, respectively) than in the control ponds without substrates (55% and 20%, respectively). Addition of substrate significantly (P

The diet of zebrafish Danio rerio in Bangladesh consisted primarily of zooplankton and insects. Zebrafish was an annual species, with the main period of reproduction commencing just before the onset of the monsoon season. Growth rates varied with age and season, with the period of most rapid growth in early life during the monsoon months.

The present study presents the results of a survey of a wide range of water bodies in Bangladesh to identify and describe Danio rerio habitat preferences. Field-based experiments were conducted to determine the vertical distribution of D. rerio in the water column, together with five other fish species commonly found in association with D. rerio. Danio rerio is a floodplain rather than riverine species, being most abundant in shallow lakes, ponds and ditches, typically in open locations with relatively clear water and abundant vegetation at the margins. It is commonly found in water bodies with a connection to rice cultivation and is more common in the north of Bangladesh than the south. Danio rerio occupies the whole of the water column and is observed as frequently in open water as amongst aquatic vegetation.