Biochemical composition of some catfishes from a coastal river of Bangladesh in relation to a biometric indicator

The proximate contents (protein, lipid, ash, and moisture) of three catfish species (Pangasius pangasius, Clupisoma garua, and Silonia silondia) were investigated from a coastal river of Bangladesh. The proximate composition was determined using the AOAC (1990) standard procedure. The average length and weight of the fish samples used in the experiment were 21.50 ± 1.61 cm and 65.55 ± 13.12 g; 19.67 ± 0.21 cm and 50.74 ± 3.13 g; 18.2 ± 1.21 cm and 43.40 ± 10.42 g for P. pangasius, C. garua, and S. silondia, respectively. The P. pangasius, C. garua, and S. silondia were rich protein sources, with 20.19%, 18.86%, and 15.24%, respectively. On the other hand, the lipid and ash contents were ranged between 2.11% to 3.07% and 0.52% to 2.28% respectively. The present study disclused water as the most abundant element in fish bodies  ranging from 75.05% (P. pangasius) to 79.60% (S. silondia). In log-transformed data, the weight of the fish body had a very significant positive relationship with most of the studied body constituents. In all three fish species, total length in log-transformed data and Fulton's condition factor showed a highly significant positive relationship with most of the studied body constituents. These findings suggest that biological differences like length and weight across species can influence the fishes biochemical composition that should be established

Morphometric relationships between length-weight and length-length and condition factor of four small indigenous fishes from the Payra River, southern Bangladesh

The present study describes the length–weight (LWR) relationship, length– length (LLR) relationship, and condition factor (K) of four small indigenous fish species from the Payra River, southern Bangladesh, namely Mastacembelus pancalus, Lepidocephalus guntea, Salmostoma bacaila and Mystus vittatus. A total of 867 specimens, representing 4 species of 4 families used for this study were caught by traditional fishing gear from July to October 2018. Standard length (SL) and total length (TL) for each specimen were measured by digital slide calipers and each body weight (BW) was taken by a digital balance. The allometric coefficient b of the LWR was close to the isometric value (b=3.078 and 3.028) in M. pancalus and L. guntea respectively, although it suggested negative allometric growth in M. vittatus (b < 3.00), whilst positive allometric growth in S. bacaila (b > 3.00). All the LWRs were highly significant (P < 0.05) and most of the coefficients of determination values were ≥ 0.857. The results further indicated that the LLRs were highly correlated (r2 ≥ 0.939; P < 0.05). Fulton’s condition factor (K) by month basis ranged from 0.52 (in M. pancalus) through 1.89 (in M. vittatus). The results of this study can be very effective for stock assessment of this four species in Payra River as well as in the surrounding ecosystems

Reproductive potential and histological profiling of the wild female anadromous shad (Tenualosa ilisha) in lower Meghna Estuary, Bangladesh

Hilsha shad (Tenualosa ilisha, Hamilton 1822) is the most commercially important and national fish of Bangladesh, belongs to the family of Clupeidae of the Clupeiformes. The study was conducted to identify the seasonal gonadal cycles through histological study and the peak breeding season combining histological and Gonado Somatic Index (GSI). One hundred and twenty fish samples with an average weight of 756.75±6.25 g was collected from the Tentulia river for the study throughout the year. Monthly mean GSI values of females ranged from 6.36±0.69 to 15.02±1.33. The lowest mean GSI value was found in December and the highest GSI value was in October. From the histological observation of the ovary, early perinucleolar stage, late perinucleolar stage, yolk vesicle stage, yolk granule stage, pre-mature and mature stages were identified. The highest percentage (75%) of mature oocytes and peak breeding season were observed in October and the breeding season continues from October to November. These results will be helpful for fishery managers to impose adequate regulations for sustainable fishery management in Bangladesh

Availability of aqua drugs and their uses in semi intensive culture farms at Patuakhali district in Bangladesh

A survey was undertaken to examine the accessibility of aqua-drugs and their applications in the semi-intensive aquaculture farms in Patuakhali district. A total of 83 stakeholders were selected and data gathered from aqua-medicine stores, representatives of different pharmaceuticals and semi-intensive aqua-farms owners via questionnaire interviews. PRA tools like focused group discussion, cross-checking, and key informant interviews were also used. Results show that 78% of farmers conduct polyculture and rest executes monoculture. Among the total fish farmer majority, 38% used lime for pond preparation and water quality management and potash used by 44% farmer as a disinfectant. For increasing dissolve-oxygen Oxy-rich (26%) was vastly used while 28% of farmers don’t use any oxygen supplier in their pond. However, 14% of farmers use commercial Megavit-Aqua growth promoters and 14% farmer used probiotics. For disease control, 52% and 14% of farmers use Renamycin and Renamox respectively due to its easy availability and affordability compared to probiotics. Several issues have been reported due to improper use of aquatic medications, such as lack of information about chemical use, sufficient dosage, form of application and indiscriminate use of antibiotics. This research result will help the policymaker to understand the requirement of fishers for healthy and sustainable aquaculture practices

Reproductive biology of Gagora catfish (Arius gagora) at Meghna river system, Kushiara River, Bangladesh

The gagora catfish, Arius gagora is a species of Ariidae family normally exist in estuaries and tidal rivers of Bangladesh and India. In the present study, the reproductive biology of A. gagora was assessed in Meghna River system at Kushiara River. Length-weight relationship was found strongly correlated for male (r2 = 0.98), female (r2 = 0.97) and combined sex (r2 = 0.81), respectively. Chi-square tests revealed no significant difference between sex ratios round the year and not deviated from the expected value of 1:1 (χ2 = 5.57) and the critical chi-square value calculated was 143.25. The fecundity found to be ranged from 43333.12±829.83 to 53948.81±1743.28 in April to August. The relationship of fecundity with ovary weight (r2 = 0.79), ovary length (r2 = 0.88), total length (r2 = 0.85) and total weight (r2 = 0.68) were found positively correlated. Monthly study of gonadosomatic index (GSI) revealed that the breeding season for this fish species may be between July to August with a single peak spawning month in August. Size at sexual maturity was estimated as 30.01 cm total length. Fulton's condition factor (K) value varied in both males and females and indicates that the overall health condition of both the male and female were excellent. Breeding season was found significantly correlated with rainfall, but not with other biological, meteorological, and hydrological parameters. Ovarian development of A. gagora was assessed macroscopically and three broad gonad developmental stages were identified. Maturity was specified based on the presence of green egg in the peritoneal cavity. These findings should benefit and improve the sustainable management and conservation of this species both in Bangladesh and its bordering countries

Weight-length, length-length relationships and form factor of three flatfish species from the Bay of Bengal, Bangladesh

Biometrics such as weight-length relationships (WLRs), length-length relationships (LLRs), as well as form factor (a3.0) were investigated for three flatfish species, Cynoglossus lingua, Cynoglossus arel, and Brachirus pan which were captured using seines and gill nets between September 2021 and March 2022 from the Bay of Bengal, Bangladesh. The lengths were measured to adjacent 0.1 cm accuracy with a digital caliper and weights to the accuracy of 0.01 g with a digital balance for each individual. The WLRs were accurately adjusted for all species (r2 > 0.9500). Brachirus pan had the lowest b value of 2.9543, whereas C. arel had the highest b value of 3.2924 amongst the three species. For the investigated species of fish, LLRs were also highly significant (r2 > 0.9600, p < 0.01). The estimated form factor values were 0.0023 for B. pan, 0.0026 for C. arel, 0.0027 for C. lingua. New maximum total lengths for C. arel and B. pan have also been recorded. Since there are no weight-length relationships (WLRs), length-length relationships (LLRs), as well as form factor (a3.0) data for these species in Bangladesh; the information supplied here expands the depth of knowledge for these species

Ichthyofaunal diversity of Basurabad Beel in regards with threat factors and conservation measures, Bangladesh

The present study was conducted to assess the temporal distribution of ichthyofaunal composition of Basurabad beel in Khulna, Bangladesh and investigated the fish biodiversity and core threats to biodiversity to provide recommendations for conservation in the beel. During the study period, total 33 fish species were recorded belonging to 6 orders. The order wise fish species availability was maximum in Perciformes (39.40%) and minimum in Beloniformis (3%). The value of Shannon-Weaver diversity index was found higher in Fultola (1.19±0.41) and lowest in Basurabad (0.68±0.17) while the maximum value of Margalef richness index found in Basurabad (1.12±0.35) and lowest in Debitola (0.68±0.34). The value of Pielou’s evenness index was higher in Boroitola (0.61±0.20) and lowest in Basurabad (0.31±0.16) however the Pielou’s index showed an uneven distribution of fish species in the Basurabad sampling point.  The value of Simpson dominance index was higher in Fultola (0.58±0.10) and lowest in Kishmath-Fultola (0.39±0.16). Ten different kinds of fishing gears were identified under 5 major groups in the beel. Among all the gears operated, seine net (Jagat Ber Jal) had the highest catch 31.3±4.1 CC/haul/day/gear (kg) followed by current jal 10.5±2.5 CC/haul/day/gear (kg). This study suggests that comprehensive studies on fisheries biology including reproductive biology, growth, stock assessment and their association with existing laws are essential for the sustainable management and conservation of fish species in the Basurabad beel

Socioeconomic, livelihood and cultural profile of the Meghna River Hilsa Fishing Community in Chandpur, Bangladesh

The goal of the study was to build a comprehensive portrait of the socioeconomic, livelihood, and cultural profile of the Meghna River fishing community in Chandpur, Bangladesh. Shatnol Malopara, an ecologically and economically suitable fishing community under the Matlab Uttor Upazila of Chandpur district, was selected for the in-depth investigation, where 410 fishermen relied solely on fishing for their livelihood. This community is made up of 185 households, supporting close to 1000 people. They are all Hindus, and fishing was their ancestral profession. A well-structured questionnaire was used to collect the data. The research revealed that the majority (35%) of fishermen were in the 18-30 age range. The community preferred nuclear families (98%), and the average family size was 5-8 individuals, which is predominant at 80%. About 60% of households lived in tiny tin shades and 40% in medium tin shades, while 60% did not have their own land. They (80%) rely on solar energy for illumination and for health facilities 50% of fisher households depend on the local pharmacy to take medication. Almost 100% of the residents in this community used potable drinking water, and 50% of fishers have ring slab latrines while the other 50% have pits. According to the survey, 60% of fishermen were very poor, 20% were poor, and 20% were moderately poor. Based on the survey, the majority (70%) of the fishermen earned between the ranges of 3000-5000 BDT (Bangladesh Taka) per month. During the ban period, the majority of fishers (50%) took out loans from various sources. Non-governmental organizations that operate microcredit businesses provided 70% of the loans to fishermen. According to the survey, 32% of fishermen had a boat and gear, while 68% worked as labor or engaged in catch-sharing with Mohajons' boats and gear. A range of crafts (Dingi nouka, Kosa nouka with mechanization) and fishing gear (Kona jal, Gulti jal, Dhon jal, Chap jal, Bada jal, Current jal, Chewa jal, etc.) was observed to be used in the study area. They have a plethora of traditional ecological knowledge as a result of their fishing ancestors. The study revealed that hilsa fishermen had a variety of issues. Extortion by local extortionists was the principal concern; other issues included inadequate credit and alternative income sources during the ban period. To assist the community in raising its standard of living, government agencies, nonprofits, and other relevant groups of organizations should adopt a number of steps. It is imperative to prioritize alternative income-generating options in this context

Growth performance and survival of oyster, Saccostrea cucullata (Born, 1778) and green mussel, Perna viridis (Linnaeus, 1758) cultivated in Bangladesh Coast

Oyster and mussel farming along the coasts and the desire to increase fishing revenue have created a boom in these types of farms. An experiment on culture of edible oyster (Saccostrea cucullata) and green mussel (Perna viridis) was performed at Gangamoti estuary in Kuakata, Bay of Bengal coast of Bangladesh from December 2021 to March 2022 to find out the appropriate culture method of the oyster, S. cucullata and green mussel, P. viridis. Initially, the average shell heights of S. cucullata and P. viridis were 8.8±1.62 and 6.9±1.89 cm, respectively; where average weights were153.4±13.23 and 84.78±11.78 g, respectively. After the culture period, oysters shell height and weight grew up to 9.1±1.98 cm and 163.2±12.54 g, respectively in rectangular basket and 8.9±1.45 cm and 157.2±11.31 g, respectively in velon screen bag. In case of oysters, the rectangular basket and velon screen bag displayed the minor progress in specific growth rate, 0.09±0.01 and 0.07±0.03, respectively. But green mussels did not show any growth rate. Oysters cultured in rectangular basket showed total mortality at day-90 and velon screen bag at day-75. Green mussels showed 100% mortality within 21 days of culture. Our experiment was the first attempt to culture these two mollusks in the Kuakata coast of Bangladesh. However, further intensive researches would be required to evaluate the culture feasibility of these two mollusks’ species in the Kuakata coast of Bangladesh.

Factors Precipitating Hypokalemia in Diabetic Patients: A Cross Sectional Study

Background: Hypokalemia is a very common electrolyte imbalance in diabetic patients which leads to substantial morbidity and mortality. Severe hypokalemia is associated with lifethreatening arrhythmias and sudden cardiac death. There are no adequate studies regarding the incidence and factors precipitating hypokalemia in Bangladeshi diabetic subjects. Objective: The objective of this study was to find out the factors precipitaing hypokalemia in diabetic patients. Materials and Methods: A total 95 admitted diabetic patients with hypokalemia were studied. Specimens were collected from all adult diabetic patients with serum potassium level <3.5 mmol/L irrespective of cause of admission. Informations were obtained in a semistructured data collection form and analyzed. Results: Most of the subjects (61.1%) belonged to the age group of 60 years and above, 31.5% to the age group 40–59 years and 7.4% belonged to the age group of 20–39 years. Sixty one (64.2%) patients were females and 34 (35.8%) were males. In 63.2% cases, vomiting was found as a factor causing hypokalemia in the diabetic patients. Other common factors precipitaing hypokalemia were diarrhea (42.1%), inadequate diet (9.5%), severe hyperglycemia (3,2%), diabetic ketoacidosis (6.3%) and drugs especially diuretics (18.9%), bronchodilators (6.3%) and steroids (5.3%). The commonest comorbidity associated with diabetes was hypertension. Conclusion: In this study the commonest precipitating factor causing hypokalemia was vomiting. Majority of hypokalemic patients were female and of older age group. When hypokalemia is identified, the underlying precipitating factor should be sought and the disorder treated. Diuretics should be used with caution in the elderly patients having hypertension, a common comorbid condition of diabetes, as these patients are susceptible to develop hypokalemia