Bangladesh Journal of Fisheries

Effects of synbiotics on innate immunity in the stinging catfish (Heteropneustes fossilis)

SADIA SALAM — 2023-12-31

An experiment was conducted to evaluate the effects of dietary synbiotic (a group of probiotics at a dose of 3.09×10⁸CFU/ml with a mixture of prebiotics) supplementations on the innate immunity of stinging catfish, Heteropneustes fossilis. A total of 1000 H. fossilis fries with an average initial weight of 2.03±0.15 g and an average length of 6.96±0.45 cm was randomly stocked into four groups T1 (control: no synbiotic), T2 (4%), T3 (6%), T4 (8%) groups. During the 45-day feeding trial, fish were fed twice a day at a rate of 3% body weight. Additionally, T2 (4% synbiotic), T3 (6% synbiotic), and T4 (8% synbiotic) received synbiotic supplementations (4%, 6%, and 8% of basal feed, respectively) once every 15 days. Results showed improvement in innate immunity of experimental units in terms of composition of WBC, Neutrophil, Basophil, Eosinophils, Lymphocytes. Though the number of WBC was not significantly higher but the increased composition of other white blood cells indicates that synbiotic supplementation can potentially improve the immunity status of H. fossilis, and the results can be supported through further investigations.

Vermicompost for fish pond: Impacts on water quality and the growth performance of Oreochromis niloticus and Anabas testudineus

MD. ABU SHAMA — 2024-08-09

The study was undertaken to assess the effectiveness and impact of vermicompost on water quality parameters in fish ponds, alongside evaluating the growth performances of two fish species, Oreochromis niloticus and Anabas testudineus. The experiment involved four separate treatment groups, namely T₁, T₂, T₃, and T₄ (control), for a period of 120 days. Vermicompost was applied at a rate of 8000 kg/ha and was used only in treatment T₁. Throughout the experimental duration, notable distinctions (p<0.05) were observed between the water quality parameters, including total alkalinity (mg/L), dissolved oxygen (mg/L), ammonia-nitrogen (mg/L), NO₃-N (mg/L), and PO₄-P (mg/L), across the vermicompost treatment and other experimental groups. These parameters showed the optimal range for fish culture in the vermicompost-treated ponds. In addition, plankton abundance differed significantly (p<0.05) between treatments, with the highest mean value observed in vermicompost (T₁) ponds (52.50±3.54×10³cells/L). Total fish production (2.19 ton/ha/120 days) was significantly higher in the vermicompost treatment than in the other treatments. This study showed that the use of vermicompost for fish pond fertilization, taking into account pond limnological conditions, provides a cost-effective and promising approach for the cultivation of Oreochromis niloticus and Anabas testudineus. This method can contribute to organic fish farming practices, appealing to consumers who value organic products.

Effect of fertilizers on the growth performance of Azolla pinnata: A potential feed additive for fish culture in Bangladesh

SHAHIDA ARFINE SHIMUL — 2023-12-31

Azolla is among the most popular, low-cost, and high-nutrient-content fish feeds. Azolla pinnata's growth performance was evaluated on the effects of fertilizers containing phosphorus and nitrogen. The study used a completely randomized design (CRD) over thirty-five days in 150 L water containers. Two sets of sub-experiments were established, each with three replications: one for the combined application of phosphorus and nitrogen and another for the sole application of phosphorus. The results showed that the combined application of phosphorus (46% P) and nitrogen (46% N) was more effective than the application of phosphorus alone. The highest cell number and protein content of combined P and N applications were (70.01±4.73 g and 33.71±2.3%) in the T4 treatment. On the other hand, the maximum cell number and protein content of the sole P application were 58.76±3.8 and 33.06±2.25%, respectively, in the T4 treatment. A Significant variation was observed in terms of the mean cell number, weight, and protein content among the experimental treatments. This study's primary focus was to demonstrate the effects of inorganic fertilizers on Azolla growth. The findings suggest that the combined application of phosphorus and nitrogen fertilizer can significantly enhance Azolla growth compared to the sole application of phosphorus.

Temporal dynamics of condition index and glochidia larval occurrence in freshwater mussel, Lamellidens corrianus (Lea, 1834) collected from a wetland of Mymensingh, Bangladesh

MD. ABDUS SALAM — 2024-08-09

We report the temporal pattern of condition index (CI), and glochidia larval presence and discharge in freshwater mussel, Lamellidens corrianus, obtained from the Darikathal Beel at Trishal upazila of Mymensingh district in Bangladesh. Samples were drawn monthly over a year from July 2021 to June 2022. The mean shell length, shell height, shell breadth, tissue wet weight, and shell dry weight were 86.29±8.36 mm, 19.31±1.42 mm, 40.31±4.90 mm, 12.52±4.77 g, and 12.05±2.85 g, respectively. The male-female sex ratio was 1.00:2.00 with no sexually undifferentiated animals in the sample.

Feasibility of rice-crab (Scylla olivacea) co-cultures in the south-west coastal ghers of Bangladesh

MD. MOTIUR RAHMAN — 2023-12-31

To assess the production performance in terms of growth, survival and intactness of mud crab in co-culture with rice plants an experiment was conducted for a period of 120 days in the ghers of two villages under Paikgacha Upazilla, Khulna. The crab juvenile was collected from adjacent Shibsha River and stocked in two experimental ghers of 0.004 ha area each without considering male female ratio. The stocking density was 50 per decimal, 75 per decimal, 100 per decimal in T₁, T₂ and T₃treatments of two experiments, respectively. Fresh chopped tilapia fish was fed to the crab and the requirement of supplied tilapia fish was adjusted periodically in accordance with the growth performance or body weight of crab. Production and physico-chemical parameters were recorded and analyzed according to standard methods. Among these parameters salinity had significant (p<0.05) role on survival of mud crab. After 120 days of rearing we obtained average final weight of cultured crab (Scylla olivacea) was 154.6±12.19g, 135.46±21.30g and 107.23±14.87g; with the estimated yield of 995.96±193.43 kg/ha, 1179.4±266.68 kg/ha and 1144.22±544.05 kg/ha, survival was 45%, 47% and 42% in T₁, T₂ and T₃ treatments respectively in Bayra village; On the other experimental site in Gopalpur village we obtained average final weight of cultured crab was 169.2±19.20g, 155.22±17.73g and 167.53±18.60g; with the estimated yield of 476.83±160.51 kg/ha, 793.73±361 kg/ha and 1636.19±868.32 kg/ha, survival was 25%, 27% and 22% in T₁, T₂ and T₃ treatments respectively The yield of rice was found 6006±1021 kg/ha, 6026±991 kg/ha, 5995±1005 kg/ha in T₁,T₂,T₃ treatments respectively in the experiment of Bayra village on the other hands in Gopalpur village the yield was 5877±1297 kg/ha, 5743±1350 kg/ ha, 5468±1190 kg/ha in T₁,T₂,T₃ treatments respectively. Results and findings of the present study suggested that yield of rice was not hampered for rice-crab co-culture in ghers. According to the experimental results poor salinity level, temperature, water level fluctuation and winter seasons are the potential constraints in the growth, survival and intactness of rice crab co-culture in the coastal ghers of Bangladesh.

The biodiversity of fish in transboundary rivers from north-eastern Bangladesh

MAHMUDUL HASAN — 2024-08-09

The biodiversity of freshwater fish is disappearing at an alarming rate around the globe, with transboundary rivers in Bangladesh being especially vulnerable. From October to December 2023, we surveyed the fish biodiversity of 11 transboundary rivers in north-eastern Bangladesh using the available literature and online FishBase data for species identification. We also added a small number of specimens from our previously examined samples that comprised of 74 fish species belonging to eight orders and twenty-four families. Our survey results indicate that the order Cypriniformes had the biggest number of species (38%), followed by the orders Siluriformes (30%), Perciformes (24%), Clupeiformes (3%), Synbranchiformes (1%), Beloniformes (1%), and Tetraodontiformes (1%). Less than 30% of the entire studied area had 26 fish, indicating that the fish population was confined to a relatively limited region. The total number of species was lower than that we had anticipated, which explains the declining trend of the fish biodiversity in the transboundary rivers of north-eastern Bangladesh. Our survey data have allowed us to gain some early understanding of the hidden biodiversity of fish in these rivers, which may prove useful to other researchers conducting follow-up studies. Since there is currently no published description of the ichthyofaunal diversity in transboundary rivers, the current data on 74 species of ichthyofauna will be useful to future researchers, planners, and policymakers. In order to safeguard the faunal composition of a riverine ecosystem, more efforts incorporating genetic data will be helpful in detecting the biodiversity of fish as well as the cryptic species of other transboundary riverine systems. These efforts will also reinforce the need to re-evaluate the checklist and promote sustainable conservation directions.