Biological features of Chanda nama (Ambassidae) in the Old Brahmaputra River, Bangladesh

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

Population Biology of the Indian River Shad, Gudusia chapra (Clupeidae) in the Old Brahmaputra River, North-Eastern Bangladesh

Population biology including population structure, reproduction, length-weight relationship and condition factor of a commercially important clupeid freshwater fish, Gudusia chapra was studied in the Old Brahmaputra River, Bangladesh during January-December 2009. In the present study, a total of 2032 specimens (1091 male; 941 female) were collected. The overall sex ratio showed significant difference from the expected value 1:1 (male: female = 1:0.86, χ2 = 11.07, p<0.001). Length-frequency distribution showed a size predominance of females over males, where mean female size consistently exceeded that of males throughout the year. Female size at first sexual maturity was estimated as 8.3 cm in standard length (SL). Monthly gonadosomatic index (GSI) was higher during March-September with a peak in April, indicating this was the main spawning season. The allometric coefficient b of the length-weight relationship (LWR) indicated negative allometric growth in males and females, but the analysis of covariance (ANCOVA) showed significant differences in slope and intercept between the sexes (p<0.001). Fulton’s condition factor by months and SLs varied in both sexes and was attributed to variations in GSI with maturity

Studies on genetic variability and interrelationship in bottle gourd [Lagenaria siceraria (Mol.) Standl]

The genetic parameters were studied to elucidate the genetic variability, correlation and path co-efficient analysis in thirty-nine genotypes of bottle gourd [Lagenaria siceraria (Mol.) Standl] in randomized complete block design with three replications. Observations were recorded for eleven quantitative characters viz., days to first male flower open, days to first female flower open, node number of first female flower, braches plant-1, days to harvest, number of fruits plant-1, fruit weight, fruit length, fruit girth, 100 seed weight and yield ton ha-1. The analysis of variance showed highly significant differences for all the characters studied indicating considerable variability among the genotypes. The highest GCV (35.57%) and PCV (35.62%) were observed for fruit length. The differences between GCV and PCV were high for fruit number plant-1 and days to first male flower open indicating environmental influences. High heritability associates with high estimates of genetic advance in percent of mean were noted for length of fruit, yield, girth of fruit and number of fruits plant-1. It indicated presence of additive gene effect and selection for these traits would be effective. Yield were positively and significantly correlated with fruit weight, 100 seed weight, branch plant-1 and number of fruits plant-1 .Negative associations of yield were noted with days to first male and female flower open, days to harvest and length of fruit. Path analysis revealed that fruits plant-1 (0.93) and weight of fruit (0.467) had very high positive effect on fruit yield ton ha-1 .Int. J. Agril. Res. Innov. &amp; Tech. 8 (1): 14-17, June, 201

UGROŽENE VRSTE RIBA U SVIJETU: Botia dario (Hamilton, 1822) (Cypriniformes: Cobitidae)

Bengal loach Botia dario is a valuable food fish in South Asian countries including Bangladesh, Bhutan, India and Nepal. However, the wild population is declining due to heavy harvest, habitat loss and its ecological changes. This paper suggests actions for the conservation of the lasting isolated populations of B. dario in Asian countries.Benegalski vijun, Botia dario, u južnim azijskim zemljama, uključujući Bangladeš, Butan, Indiju i Nepal, ima visoku važnost u prehrani. Međutim, divlje populacije su u opadanju zbog teškog iskorištavanja, gubitka staništa i ekoloških promjena. U ovom članku se predlažu akcije za očuvanje posljednjih izoliranih populacija B. dario u azijskim zemljama

RAST JEDNOSPOLNE I NILSKE TILAPIJE MJEŠOVITOG SPOLA U UVJETIMA PREZIMLJAVANJA NA SJEVEROISTOKU BANGLADEŠA

The study was conducted to assess the over-wintering growth performance of mixed-sex and mono-sex male tilapia, Oreochromis niloticus. The experiment was carried out with two treatments each with three replicates for a period of 6 months from October, 2012 to March, 2013 in the Field Laboratory Complex, Bangladesh Agricultural University. In the first treatment (T1), mixed-sex tilapia was stocked in 3 ponds with a mean initial weight of 4.80±0.18 g. In the second treatment (T2), mono-sex male tilapia was stocked in another 3 ponds with a mean initial weight of 4.81±0.20 g. Fish were fed at the rate of 6% of fish body weight at the beginning of the experiments then the feeding rates were gradually reduced to 2% for the third month and finally increased to 3% for rest of the period. Water parameters in terms of temperature, dissolved oxygen, pH, transparency, alkalinity, ammonia and nitrite were within the range of fish farming. After 6 months of culture period mono-sex male tilapia attained a significantly (P0.05) difference of food conversion ratio and survival rate (%) values between the treatments. The benefit-cost ratio was calculated as 1.17 and 1.43 for mixed-sex and mono-sex male tilapia, respectively. The results suggested that it is possible to successfully culture tilapia during the winter period in Bangladesh and the culture of mono-sex tilapia is more profitable due to its higher growth rate.Cilj ovog istraživanja bila je procjena rasta nilske tilapije mješovitog i muškog spola, Oreochromis niloticus, u uvjetima prezimljavanja. Eksperiment se sastojao od dva tretmana s tri ponavljanja u razdoblju od 6 mjeseci, od listopada 2012. do ožujka 2013. godine na vanjskim bazenima (Field Laboratory Complex) Poljoprivrednog sveučilišta u Bangladešu. U prvom tretmanu (T1) je tilapija mješovitog spola prosječne početne težine 4,80 ± 0,18 g bila smještena u 3 ribnjaka. U drugom tretmanu (T2), tilapija muškog spola prosječne početne težine 4.81 ± 0.20 g bila je smještena također u 3 ribnjaka. Na početku eksperimenta ribe su bile hranjene po stopi od 6% od njihove ukupne tjelesne mase, a potom su stope hranjenja postepeno smanjivane do 2% u trećem mjesecu te na kraju povećane na 3% u preostalom vremenu. Parametri vode poput temperature, otopljenog kisika, pH, prozirnosti, alkaliniteta, amonijaka i nitrita bili su u skladu s vrijednostima pogodnima za uzgoj ribe. Nakon 6 mjeseci uzgoja, tilapija muškog spola dosegla je značajno veću prosječnu konačnu težinu (P 0,05) i postotku stope preživljavanja (%) između tretmana. Rezultati su pokazali mogućnost uspješne kultivacije tilapije u zimskom periodu u Bangladešu, s time da je uzgoj jednospolne tilapije isplativiji zbog njezine veće stope rasta

Following things of rubbish value: end-of-life ships, ‘chock-chocky’ furniture and the Bangladeshi middle class consumer

There has been an upsurge of geographical work tracing globalised flows of commodities in the wake of Appadurai’s (1986) call to ‘follow the things’. This paper engages with calls to follow the thing but argues that work thus far has been concentrated, first, on global flows from developing world producers to developed world consumers, and, second, on things that remain stable as they circulate. This paper instead argues that ‘follow the thing’ research needs to also attend to flows ’down’ the value chain, from developed to less developed worlds, and to things that are either coming apart or being disassembled. The case presented here is end-of-life ships, sent to be broken in less developed countries, as most are, in this case in Bangladesh. It looks at how the arts of transience re-work materials from rubbish value ships into new forms and objects in the household furnishing sector, which are then appropriated by Bangladeshi middle class consumers. Far from being a minor feature this is shown to be empirically a significant component of the Bangladeshi economy. Theoretically the paper challenges many habitual assumptions about global flows of commodities and urges ‘follow the thing’ research to rethink the thing. Paying attention to the back-end of the value chain shows that things are but temporary configurations of material. At best partially stable, things are argued to be endlessly being assembled, always becoming something else somewhere else

Growth and longevity of the mola carplet Amblypharyngodon mola (Cyprinidae) in the Payra River, southern Bangladesh

The growth and longevity of Amblypharyngodon mola was studied in the Payra River, southern Bangladesh, using length-frequency distributions during February 2016–January 2017. Both males and females first recruited in June, with modal size around 25 mm standard length. Growth for both sexes was described by the von Bertalanffy growth equation as: Lt = 50.10[1 − exp {−0.145(t + 2.926)}] for males and Lt = 51.64[1 − exp {−0.135(t + 3.326)}] for females. Both sexes showed similar growth patterns as no significant difference was observed between the sexes (F-test, F = 1.89; p = .167). The longevity of this species was estimated to be 1 + year (13 months for males and 15 months for females). Standard length vs. body weight relationship indicated an isometric growth in both sexes. However, ANCOVA revealed significant differences in intercept (p < .05) between sexes, though not with slopes (p = .420)

Dynamics of cyanobacteria planktothrix species (Oscillatoriales: Phormidiaceae) in Earthen fish ponds, Northwestern Bangladesh

The seasonal abundance, dynamics and composition of the filamentous Cyanobacteria Planktothrix spp. was studied over a 1-year period in two storm-water-fed earthen fishponds in Rajshahi city, northwestern Bangladesh. Sampling was conducted monthly using plankton net (25 μm mesh size) and the samples preserved in 5% formalin. Water quality parameters including water temperature, transparency, pH, dissolved oxygen (DO), biological oxygen demand (BOD), free carbon dioxide (CO2), nitrite-nitrogen (NO2-N), nitrate-nitrogen (NO3-N), ammonium (NH4 +), oxidation reduction index (rH2) were recorded during each sampling. Two species; Planktothrix agardhii and Planktothrix rubescens were identified during the study with P. agardhii recording higher abundance (p<0.05) all year round. The Planktothrix cell density was highest during March: 3.06×106 cells/L and 1.23×106 cells/L in Pond-1 and 2, respectively. The abundance of P. agardhii was relatively higher in spring. The cell densities increased with increasing temperature, pH, and nutrient concentration. Lower cell densities were recorded during periods of high BOD. The results of this study provide a useful guide for aquaculturists and other environmental scientists for the management of the cyanotoxin producing algal blooms of Planktothrix spp. in fertilized fish ponds and other aquatic habitats

Effects of stocking density on survival, growth and production of Thai climbing perch (Anabas testudineus) under fed ponds

An experiment was carried out in 6 earthen ponds to investigate the effects of stocking density on growth, survival and production of Thai climbing perch (Anabas testudineus). Three stocking densities (treatments) were compared: ponds with 350, 400 and 550 individuals per decimal (0.01 acre). All treatments were randomly assigned and in duplicate. Artificial feed containing 34% crude protein was applied initially 20% of total fish weight per day. Gradually the feeding rate was reduced to 15, 12, 10, 8 and 5% of total fish weight per day. Feeding rates per pond were adjusted fortnightly after weighing minimum 20% of the fish stocked. The duration of the experiment was 90 days. Results showed that all growth parameters were higher in ponds with lower stocking density than the ponds with higher stocking density, while total fish yield was higher in ponds with higher stocking density than in the ponds with lower stocking density. Cost-benefit analysis revealed that all three systems were economically profitable. However, the ponds with a stocking density of 550 individuals per decimal were the most profitable system. More research is still needed to further optimize stocking density of Thai climbing perch in aquaculture ponds. Until then, stocking 550 individuals of Thai climbing perch per decimal will yield a good production to fish farmers in the South and South-East Asian region