Major carps are prevalent species in the aquaculture sector due to their greater growth, ease of maintenance, and ability to thrive in the country’s excellent agricultural conditions. However, the natural carp spawn supply is predominantly declining as a result of environmental and anthropogenic causes in the natural spawning grounds. The study’s objective was to identify natural spawning areas for carp species in the Surma River (Sylhet haor basin). The research was carried out throughout the spawning season for carp species, which occurred from March to August 2021. The sample of spawn was collected by putting four Savar nets at the Surma River’s Hetimganj and Golapgonj points and then keeping them in the Sylhet Agricultural University Mini Hatchery to identify the carp species by microscopic and physical examination. According to the results, 35 species of spawn were identified, where 31% carp, 23% barbs and minnows, 5% loaches, 16% clupeids, 3% snakeheads, 8% perch, 5% catfish, 2% eels and mud eels, and 7% miscellaneous. Among carp spawns, there were 37% gonia, 56% kalibaus, and 7% bata. Despite the ideal natural conditions for spawning, the study also found that the climate was unfavorable because of untimely rainfall, climate change, and other human causes. The Surma River, however, may contain carp spawn considering that numerous carp species were found there.
The Halda River and Haor basins are considered unique breeding habitats for carps in Bangladesh. The purpose of the study was to evaluate the natural spawning environment of carp species, with an emphasis on the hydrological conditions of the Halda River, the Surma River, and Tanguar Haor. This study, which covers the years 2021 and 2022, considered two spawning seasons. The results revealed that temperature, total dissolved solids (TDS), salinity, turbidity, conductivity, and pH were significantly different in the Halda River to the Surma River and Tanguar Haor. However, sudden rainfall and upstream runoff in 2021 were deemed as major factors causing an increment in TDS and electrical conductivity. The water pollution index was excellent in the Surma River and Tanguar Haor, and good in the Halda River. The study reported moderately reduced IMC fry production in 2021 because of inconsistent turbidity, high conductivity, and increased salinity which interrupted the ideal spawning habitat. However, in 2022, the spawning environment was favorable in the Halda River, while the Surma River and Tanguar Haor were considered to be comparatively favorable in both years. Differences were also found in the climatic and meteorological conditions, which revealed uneven rainfall, higher temperatures, decreasing water discharge, and low water levels. The meteorological data also revealed that the overall rainfall showed a decreasing trend for all sites in the last 20 years causing an interrupted water discharge. It was discovered that the amount of carp spawn obtained in the Halda River was greater than that obtained in the Surma River and Tanguar Haor. In terms of hydrological conditions and spawning performance, the Surma River and Tanguar Haor were reported to have significant differences, which may be due to their geographical location.
The purpose of this study is to compare the effects of probiotics, prebiotics, and their synergism against antibiotics on the growth performance and hematology of Nile tilapia (Oreochromis niloticus). The study was designed by using five treatments over 75 days in which TCon (control), TAnt (antibiotics: Cotrim vet), TPro (commercial probiotics: pond care), TPre (prebiotics: spirulina), and TSyn (synbiotic: probiotic and prebiotic) were used. All the treatments showed significant ( P < 0.05) improvements in growth and feed utilization parameters. The highest mean final growth was found in TSyn (13.79 ± 0.11) and then in TPre (13.61 ± 0.02), TPro (13.22 ± 0.12), TAnt (10.04 ± 0.7), and TCon (8.89 ± 0.19). Weight gain and specific growth rate were significantly ( P < 0.05) different between treatments. The food conversion ratio varied significantly ( P < 0.05) across treatments and the lowest value was observed in TPro (1.13 ± 0.021). The protein efficiency ratio (PER) was significantly ( P < 0.05) different between treatments and the highest value was in TPro (3.1 ± 0.05). The survival rate was not significantly ( P < 0.05) different between treatments. The highest white blood cell (WBC) counts were found in TSyn (12.63 ± 0.11) followed by TPre (12.6 ± 0.2), TPro (12.32 ± 0.12), TCon (12.16 ± 0.105), and TAnt (11.03 ± 0.46). The values of red blood cells and platelets were not statistically significant ( P < 0.05) among the different treatments. However, all treatments showed normal hepatocyte structure in liver tissue histology, and intense hepatic lipid vacuoles in TSyn indicated improved growth. The higher growth performance and feed utilization values were observed in probiotics, prebiotics, and their synergism units compared to antibiotic treatment. Therefore, probiotics, prebiotics, and their synergism can be used as an alternative to antibiotics in tilapia aquaculture.
Climate change is causing widespread concerns along the coast, reducing agricultural productivity and destroying livelihoods. A study was conducted in two cyclone-prone districts of Bangladesh, Khulna and Satkhira, with a focus on women, to improve the climate-resilient livelihoods of coastal communities. Participatory rural appraisal techniques were used to collect community perceptions of climate change and variability, as well as adaptation options. A total of 699 participants were involved, where 466 respondents were in the treatment group mostly vulnerable to climate change, and 233 were in the control group similarly matched to the treatment groups. Female respondents were adequately involved in this research and accounted for 63% of the treatment and 60% of the control areas. Climate change was impulsive, according to the findings, and variability has increased over time with no optimistic outlook. The women had an idea about climate change, with 62.7% in the treatment group and 58% in the control group being aware of it. About 55.3% in treatment and 45% in control were willing to take preventative measures against climate change. Natural disasters and difficulty in selling their products impacted agricultural harvests, and as a result, both the treatment and control groups attempted to adapt to the alternative livelihoods in response to climate change. Respondents cited changes in rainfall patterns, cyclones, saline water intrusion, and other factors as causing lower yields and crop damage. To improve the adaptive capacities of their climate-resilient livelihoods, communities adapted to the changing environment by accepting high-yielding salt-tolerant varieties, introducing new technologies, and modifying livelihood options.
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