孟加拉涝原地区村林居住的宗教社团偏爱的乔木和灌木树种及使用的造林材料研究

2002年1月至6月对孟加拉涝原地区两个不同的宗教部落(印度教和穆斯林教)的传统家园森林进行了探索性研究，包括印度教和穆斯林教社团对树种(乔木和灌木)的偏爱度、类似性、造林材料及来源、植树地点和间距。研究发现Mangifera indica作为乔木树种，Ocimum sanctum作为灌木树种为印度教社团最喜爱的树种；Artocarpus heterophyllus和Lawsonia inermis分别为穆斯林社团最喜爱乔木树种和灌木树种。两中不同宗教社团选择乔木数种的相同性为86．57％，灌木树种为78．48％。两个宗教部落使用种子和苗木作为造林材料最多。乔木树种的造林材料主要来自家园(39％)灌木树种主要来自自然界(40％)。表3参27。     

Application of Biofloc Technology for the culture of Heteropneustes fossilis (Bloch) in Bangladesh: stocking density,floc volume,growth performance,and profitability

Though Biofloc Technology is a new concept in Bangladesh, it provides advantages for improving aquaculture production in many countries, leading to achieve sustainable development goals. The objectives of this study were to determine the effects of stocking densities on the growth performance of stinging catfish (Heteropneustes fossilis) under Biofloc Technology and assess the economic prospects and business feasibilities. Fingerlings were stocked in unique 5000-L tanks with three stocking densities, i.e., 3500 fish/tank (Treatment-I), 4000 fish/tank (Treatment-II), 4500 fish/tank (Treatment-III). The treatments showed significant differences (P?<?0.05) considering the species-specific growth rate, feed conversion ratio, and protein efficiency ratio. Treatment-I had significantly ((P?<?0.05) higher final biomass (29.51 ± 0.04 kg/m³) than the other treatments. The present findings revealed that using a lower stocking density, the Biofloc Technology reduced ammonia (NH₃), nitrite (NO₂), nitrate (NO₃), TDS, and floc volume but significantly increased the dissolved oxygen. As a result, Treatment-I had generated significantly higher net income (BANGLADESHI TAKA—BDT 86,278.90) over the other treatments. Moreover, the NPV, net BCR, and RoR with 4% and 9% opportunity cost were also significantly higher in Treatment-I than other treatments. The internal rate of return (IRR) and SWOT analysis index indicates that investing in Biofloc Technology is far superior, and a stocking density of 3500 fish/tank (Treatment-I) resulted in a faster investment return.

     

Performance of pyrazosulfuron-ethyl in non-puddled transplanted rainy season rice and its residual effect on growth of the succeeding crop in rice-wheat cropping pattern

Abstract

A study was carried out in sandy clay loam textured soil of Mymensingh, Bangladesh to evaluate weed control efficiency of pre-emergence herbicide pyrazosulfuron-ethyl either alone or in sequential application with post-emergence herbicide in transplanted rainy season rice under non-puddled strip-tilled (NPST) field condition and also to examine the residual effect of those herbicides on germination and growth of the subsequently grown wheat crop. Five treatment combinations of pyrazosulfuron-ethyl were tested against one weedy check and one weed-free check. The study revealed that NPST rice field was mostly infested by grass and sedge weeds and herbicide treatments offered a wide range of control (above 50% to 95%) on all types of weeds. Application of pyrazosulfuron-ethyl followed by (fb) orthosulfamuron fb butachlor plus propanil provided the most effective and economic weed control over two years of the study. Moreover, micro-plot bioassay study claimed germination and growth of subsequently grown wheat were not adversely affected by herbicides that were applied in rice. Therefore, application of pyrazosulfuron-ethyl followed by post-emergence herbicide could be effective and economic to control weeds in NPST rice under rice-wheat system, but proper rate and time of application should strictly be followed.     

The interactive effects of paternal size and offspring feeding strategy on offspring fitness of an Indian major carp Labeo rohita (Hamilton, 1822)

Parental condition‐dependent offspring fitness is a well‐discussed issue in animal breeding research, while offspring environment and its interaction with parental condition are currently another very interesting topic to investigate the plasticity of phenotypic traits across an environmental gradient. The present study was, therefore, conducted following a half‐sib breeding design to test the effects of (a) paternal body size, (b) offspring feeding strategy (everyday and every other day) and (c) their interactions on fitness‐related traits (e.g., survival, total length and body area) of offspring of a commercially important aquaculture species, the Indian major carp (Labeo rohita). The analysis revealed that paternal body size had significant effects on offspring survival rate and total length, while no significant influence was found in body area. The study also showed that the offspring feeding strategy significantly affected all offspring traits. Interestingly, the study unveiled the significant interactive effects of paternal condition and offspring feeding for offspring survival rate and total length. These findings suggest that paternal size, offspring rearing environment and their interactions can influence offspring fitness‐related traits which are very essential information for the sustainable production of good quality larvae under variable dietary conditions.     

Effects of light and artificial fish shelter (PVC pipe) on some phenotypic traits of stinging catfish (Heteropneustes fossilis Bloch, 1794)

Light and shelter are very important ecological factors that can affect many traits of fish. Therefore, a study was conducted to explore the effect of light and shelter on some phenotypic traits of stinging catfish (Heteropneustes fossilis Bloch, 1794). During experiment, equal‐sized juveniles (mean ± SE: 9.04 ± 0.09 cm) were collected and reared in aquariums dividing into four treatment groups, such as T₁ (0L:24D without pipe), T₂ (0L:24D with pipe), T₃ (12L:12D without pipe) and T₄ (12L:12D with pipe). Each treatment had 36 fish, which were randomly distributed into three replications. The fish were kept up to 120 days, and then, the growth performance and skin colour were analysed. The results showed that both lighting and shelter conditions as well as their interactions had significant effects on some traits expression. The analyses revealed that lighting condition significantly influenced body area, head width and skin coloration, while shelter condition significantly affected total and standard length, body area, and their interaction showed significant effects on body area, head width and anal fin length. Thus, this study indicates that stinging catfish show better growth performance and colour patterns especially in dark and sheltered conditions which could be recommended for the successive production of this highly priced fish species.     

Dietary supplementation of host‐associated lactic acid bacteria modulates growth,metabolic activities,and immune‐related gene expression in giant freshwater prawn,Macrobrachium rosenbergii

The present study was carried out to evaluate the dietary effects of host‐associated lactic acid bacteria on growth performance, metabolic enzyme activities, and immune response of Macrobrachium rosenbergii juveniles. To formulate the test diets, a control (Con) diet was supplemented with a commercial probiotic and three host‐derived bacteria Enterococcus faecalis (EC), Lactococcus lactis I (LC‐I), and L. lactis II (LC‐II), which were previously isolated from the gastrointestinal tract of adult individuals of M. rosenbergii. Juvenile M. rosenbergii (0.65 ± 0.008 g) were randomly stocked at 20 individuals/100 L of fiberglass tanks with three replications for each test diet. After 50 days, juveniles fed the diets LC‐I and LC‐II showed significantly higher (p < .05) weight gain, specific growth rate, and the lowest feed conversion ratio. The analyses of glutamic oxaloacetate transaminase and glutamic pyruvate transaminase in muscle and hepatopancreas revealed significantly (p < .05) reduced values in LC‐I fed juveniles. The total hemocyte count and phenoloxidase activity were significantly increased (p < .05) in LC‐I and LC‐II fed juveniles. The relative mRNA expression patterns of immune‐related α2‐M, LGBP, ProPO, Cu, Zn‐SOD, TG, PE, AKP, and ACP genes were significantly (p < .05) upregulated in juveniles fed with LC‐I followed by the diet LC‐II. Finally, the study suggests that the growth performance and immune response of M. rosenbergii can be improved through supplementation of host‐associated L. lactis bacteria for its higher production.     

Population structure of Nga Myin Yinn Silonia silondia in the Ayeyarwady River,Myanmar, by mitochondrial DNA markers

Fisheries Science - The Silond catfish Silonia silondia, locally known as Nga Myin Yinn, is a commercially important fish in Myanmar; however, fundamental knowledge of its population structure is...     

Annually twice induced spawnings provide multiple benefits: Experimental evidence from an Indian major carp (Catla catla,Hamilton 1822)

Multiple spawnings are special reproductive tactics that many fish evolved to obtain different types of direct and/or indirect spawning benefits. This has led to two pertinent questions: (a) what types of benefit does a commercially important fish provide during multiple induced spawnings annually? and (b) is there any trade‐off between traits during these spawnings? To address these questions, the present study was carried out with two separate experiments during two spawning events of an Indian major carp (Catla catla) to assess: (a) male's spawning performances and (b) female's spawning performances. The male's spawning data revealed that they produced significantly higher amount of milt and hatchlings during the first spawning, while they significantly reduced hatchling deformation rate, enhanced offspring survival rate and enlarged offspring body size during the second spawning. The female's spawning information unveiled no significant differences in total egg weight, hatching rate and hatchling deformation rate between the first and second spawning. However, females had significantly higher offspring survival rate during the first spawning and enhanced offspring body size during the second spawning. Interestingly, the analysis of trait associations revealed that males allocated energy with a trade‐off between milt weight and offspring survival rate, whereas females showed a trade‐off between hatching rate and offspring survival rate. Thus, the study provides some important information for carp breeders and associated stakeholders to know which spawning season is preferable for the higher production of eggs, milt and good quality larvae.     

Efficacy,phytotoxicity and economics of different herbicides in aerobic rice

Abstract

Aerobic rice is a potential water-wise rice production system, but high weed infestation has threatened its sustainability, which demands an efficient and cost-effective weed management technique. Eight commercial herbicide products were applied singly or as tank-mix or in sequence to evaluate their efficacy, rice selectivity and cost-effectiveness in aerobic rice. The study was conducted under field conditions in Malaysia during 2010/2011 following a randomized complete block design. Most of the herbicide treatments provided excellent weed control, and produced much higher net benefit than weedy or weed-free check. None of the herbicides caused significant phytotoxicity to rice plants. Among the herbicide treatments, sequential application of Cyhalofop-butyl+Bensulfuron at early growth stage followed by Bentazon/MCPA at mid growth stage provided the highest weed control efficiency, productivity and net benefit. Application of Bispyribac-sodium at early growth stage followed by Bentazon/MCPA at mid growth stage performed very close to the above-mentioned treatments. Sequential application of Pretilachlor/safener just after seeding followed by Propanil/Thiobencarb at early growth stage also provided satisfactory results in terms of efficacy and economic return. Since manual weeding was not economic, herbicide rotation using the above chemicals may be recommended for effective weed management in aerobic rice.     

Multi-criteria evaluation approach to GIS-based land-suitability classification for tilapia farming in Bangladesh

Site selection is a key factor in any aquaculture operation, because it affects both success and sustainability. It can, moreover, solve conflicts between different activities, making rational use of the land. This study was conducted to identify suitable sites for development of Nile tilapia (Oreochromis niloticus) farming in Sitakunda Upazila (sub-district), Bangladesh, using GIS-based multi-criteria evaluation of water and soil quality, topography, infrastructure and socio-economic factors. ASTER image and eighteen thematic layers were analyzed using ENVI and ArcView software to identify the suitable areas for tilapia farm development. A constraint layer was used to exclude areas from suitability maps that cannot be allowed to implement tilapia farming. A series of GIS models were developed to identify and prioritize the most suitable areas for tilapia farming. The output of the model clearly indicates the location and extent of tilapia farming areas on different suitability scales, i.e. most suitable (7,744 ha), moderately suitable (2,479 ha), and not suitable (838 ha). Model outputs were assessed against field verification data, and were consistent. Because existing aquaculture covers only 1,540 ha of land in the study area, the potential for expanding tilapia farms should take into consideration socio-political and environmental issues. The results are encouraging in terms of tilapia culture development and suggest that grassland–agriculture areas could be used for sustainable development of tilapia farming to diversify the economic activities of rural communities.