Bangladesh Journal of Fisheries

Response of Macrobrachium rosenbergii juvenile against a virulent isolate of Vibrio sp. from a diseased Penaeus monodon

2023-12-08T02:06:00+00:00

The present study investigated the in vivo virulence of a Vibrio sp. isolated from a diseased tiger shrimp (Penaeus monodon) and determined the median lethal concentration (LC₅₀) of Vibrio sp. against giant prawn (Macrobrachium rosenbergii) juveniles at the cell densities of 10⁴, 10⁵, 10⁶, 10⁷ CFU/mL. In addition, the survival rate of M. rosenbergii was examined through a bath challenge test against the Vibrio sp. isolate at different cell densities. The results showed that the median LC₅₀of Vibrio sp. for M. rosenbergii was 10⁶ CFU/mL by probit-transformed responses. Vibrio sp. concentrations had no effect on the mortality of prawn juveniles; however, infection time might significantly increase the mortality (p = 0.000). Lower survival of prawn juveniles was also recorded at the bacterial cell density of 10⁶ CFU/mL. Finally, Vibrio sp. cell density 10⁴ CFU/mL showed lower cumulative percent survival and higher hazard function compared to other concentrations. This study provides an indication that pathogenic Vibrios of tiger shrimp can be a potential risk for M. rosenbergii larvae culture. Further studies should be conducted to unravel the mechanism of actual mortality factor, possibly quorum sensing regulatory activities of the Vibrio sp. isolate.

Assessment of fish biodiversityin the Padma river fromFarakka Barragepoint to the Shampur Nagar Ghat, Rajshahi, Bangladesh

2023-12-08T10:59:27+00:00

The Padmariver starts from the Himalayas and enters into Bangladesh through the district of ChapaiNawabganj. Farakkabarrage has resulted in a significant alteration in the richness of fish in thisriver. We assessed the fish biodiversity of the Padma river through river and local market visit. The current investigation yielded a total of 37 fish species, divided into 9 orders and 17 families. The highest number of fish belongs to order Cypriniformes (43%) followed bySiluriformes (19%), Perciformes (16%), Clupiformes (11%); whereas the threatened fish species encountered 35% (Vulnerable 8%, Endangered 24% and Critically Endangered 3%), based on IUCN Bangladesh (2015) criteria. The obtained result argued that the abundance of fish biodiversity at the Padma river is sharply declining and many fish species is now under threat due to anthropological effect.

Integrated farming of stinging catfish (Heteropneustes fossilis) and rabbit (Oryctolagus cuniculus) in farmer’s pond

2023-12-08T11:13:39+00:00

A study was carried out to evaluate the growth and production performances of stinging catfish (Heteropneustes fossilis) and rabbit (Oryctolagus cuniculus) under two treatments such as T₁(shing-rabbit integrated system) and T₂(shing monoculture) in farmers’ pond. Twelve ponds from two villages such as Sutiakhali and Salakandi under Mymensingh sadar upazila were selected for the study. The average pond size was 5.5±0.23decimal with a stocking density of 600 shing dec^-1. The ponds were only fertilized with rabbit dung except at the time of pond preparationat a rate of 1 kg dec^-1. Various environmental parameters such as temperature (^oC), transparency (cm), PH, dissolve oxygen (mg L^-1), PO₄-P (mg L^-1), NO₃-N (mg L^-1), NO₂-N (mg L^-1), NH₃-N (mg L^-1), chlorophyll and alkalinity (mg L^-1) were monitored once in a week. The parameters were found to vary little from pond to pond and most of the parameters were within the suitable range for freshwater aquaculture in Bangladesh. The highest survival rate of fish was 95.36 ± 0.15 % in treatment T₁ and the lowest was 90.39 ± 0.10 % in treatment T₂. The survival rates of fish were not significantly different among the treatments (P > 0.05). The production of fish in T₁and T₂treatment was 25.36 and 20.43 kg dec^-1, respectively. Daily growth of shing in two treatments were 1.95 ± 0.01 and 1.88 ± 0.01 % respectively. The study revealed that integrated shing-rabbit would be highly profitable using improve extensive culture system in the rural household ponds through effectively reducing the use of pond fertilizer and fish feeding cost.

Assessment of bacterial loads and water quality parameters of three different types of fish pond

2023-12-08T11:32:45+00:00

The present study was conducted to determine bacterial loads in the water columns and mud of three different pond systems,includingan overwintering fish fry pond,a brood fish rearing pond, anda recreational fish pond (L-shaped fish pond) situated at the Field Laboratory Complex of the Faculty of Fisheries, Bangladesh Agricultural University, Mymensingh.Three samplings were done atevery 15-day interval. Bacterial loads in water columns and mud were determined using the drop count method. Water quality parameters, including temperature, dissolved oxygen, pH, and ammonia, were also determined. Significantly (p<.001),the highest bacterial loads in three different water columns were observed in the overwintering fish fry pond, and the lowest bacterial loadswere found in the L-shaped fish pondat all sampling points. Bacterial loads in the bottom water were also significantly higher than those in the surface and middle layers of the water in all ponds. Pond mud was significantly (p<.001) richer in bacterial loads than pond water. Bacterial load was strongly correlated with temperature, and the correlation faded with the increase in depth of the water column.

Population structure of Indian river shad, Gudusia chapra (Hamilton, 1822) from the Rupsha River, south-west Bangladesh

2023-12-08T11:46:51+00:00

The Indian river shad, Gudusia chapra, is a well-known species of potamodromous fish belonging to the Clupeidae family. The main focus of this study is to state the sex ratio, growth pattern, length-length relationship, form factor, Fulton’s condition factor and relative weight of G. chapra harvested from the Rupsha River (south-west Bangladesh). Altogether 300 specimens (male=166 and female=134) were harvested with the help of commercial fisher folks on seasonal basis (summer, rainy and winter) during 2022. Body weight and length of individual specimen were recorded with digital balance and measuring board. Total length varied between 12.7 to 16.5 cm for males and 13.0 to 17.3 cm for females. Further, body weight ranged between 15.82 to 42.48 g for male and 18.36 to 46.65 g for female. As a whole, both sexes revealed positive allometric growth pattern (b>3.00). Moreover, the length-length relationships were found highly correlated for both sexes. The estimated form factor was 0.0087 indicated fusiform body shape for G. chapra population. The mean Fulton’s condition factor was recorded close to 1 indicated a pleasant health condition for this species. Further, mean relative weight revealed a sound ecological atmosphere regarding prey-predator status. The research outcomes would be helpful to execute a sound management policy in the Rupsha River and connected ecosystem in the south-west Bangladesh.

Impact of fishing ban on socioeconomic status of Hilsa fishers in Bangladesh

2023-12-08T11:59:50+00:00

Fishing ban is a useful regulatory measure for sustainable management and conservation of hilsa shad (Tenualosailisha) in Bangladesh. This study investigated the socioeconomic status of hilsa fishers, as well as their perceptions regarding the performance of fishing bans and coping strategies. Data were collected from 300 fishers residing in the three study areas by using semi-structured questionnaire to collect data related to the livelihood and socioeconomic variables of the fishers. Besides, fishers’ perceptions regarding the performance of the ban as well as income generated from other activities during the fishing ban were also incorporated. Focus Group Discussions (FGD), Crosscheck Interviews (CI) with key informants’ interview was also conducted to collect general information and to justify the collected information. The majority of the fishers feel the bans have resulted in positive socioeconomic impacts which enhance their income and livelihood status from fishing. However, its impact on loss of income and level of unemployment during ban forced some fishers to drive away the ban. In contrast, diversified alternative livelihood options have been adopted by fishers to cope with the ban that not only pull them out from dependency solely on hilsa fishing but also reduce the fishing pressure on the hilsa fishery as well as fish biodiversity. The study showed a positive correlation between fishing ban and resources’ sustainability. In spite of the difficulties faced by fishers during ban, majority of the fishers support the ban for the long-term conservation of hilsa as it is their basic sustenance.

Profitability and factors affecting production of pond fish culture under NATP project in Tangail district of Bangladesh

2023-12-08T12:12:12+00:00

Profitability and input use efficiency of pond fish culture was studied at farming systems Research and Development (FSRD) site, Atia, Tangail from July 2019 to June 2020. The average pond fish production was recorded at 2808 kg/ha/year with the highest yield from the medium farms (2940 kg/ha/year) and lowest yield from marginal farms (2624 kg/ha/year). The highest gross return (Tk 352,800/ha) was found with medium farmers followed by small farmers (Tk 343,200/ha). The benefit cost ratio was also recorded higher (2.08) in marginal and small farms. Considering the aggregate production function for all groups of farmers, it was found that inorganic fertilizer, organic fertilizer, feed and human labour were statistically significant in explaining the variation in pond fish output but the results varied with different farm categories. Since there was positive correlation between input use and production of fish, it is probable that an increase in application of inputs could increase production further.

Impact of aquaculture on crop productivity in greater Noakhali, Bangladesh

2023-12-08T12:26:14+00:00

Aquaculture expanded to a great extent in Bangladesh through the conversion of agricultural lands due to high profitability resulting in land-use conflicts. The present study is the first initiative to elucidate the impacts of aquaculture on agricultural farms of greater Noakhali (Noakhali, Feni, and Lakshmipur), Bangladesh. Soil and water samples were drawn from 240 selected farms from fish farms (FF), near land (NL), distance land (DL), and control sites. Soil and water quality parameters were analysed following standard methods. A pre-coded structured questionnaire-based interview of farmers was performed from July 2017 to March 2018. Organic matter, organic carbon, total nitrogen, and pH (soil and water) of FF showed significant influence on its surrounding agricultural lands but sulfur, boron, and potassium did not show such kind of influence in all three districts. Total fish production and gross profit were found higher in large fish farms (32.19 MT/year and 238.24%) compared to medium and small fish farms. NL's total crop production and gross profits also showed the same pattern but DL’s showed the opposite pattern. Aqua farms negatively impacted agriculture in terms of cropping patterns but showed an increasing rate for HYVs (High Yield Variety) of rice in greater Noakhali.