Journal of Fisheries (University of Rajshahi)
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Length-weight relationship, relative condition factor and fecundity of Notopterus notopterus (Pallas, 1769) from river Brahmaputra in Dhubri, Assam, India
Get PDFNotopterus notopterus (Pallas, 1769) commonly known as bronze featherback is an important freshwater fish widely distributed in deep and clean waters in the rivers, beels, reservoirs and ponds. This study elucidates the length-weight relationship (LWR), relative condition factor and fecundity of N. notopterus collected from the river Brahmaputra in Dhubri, Assam, India. A total of 181 fish specimen were sampled. The LWR showed a positive isometric growth with uniform increase in height or width with increasing length. The value of a and b in males were 0.0120 and 3.06 respectively. In females, a and b were slightly higher being 0.0230 and 3.18 respectively. The coefficient of determination for combined sex was equal to 0.8572 (p < 0.001). The relationship between the fecundity and four variables viz. total length, body weight, gonadal length, gonadal weight were analysed and the relationship between the fecundity and gonad weight was much more significant than other variables considered. The current study might serve as a valuable guideline for establishing future biometric studies for fishes collected from this stretch of the river Brahmaputra
Expansion of aquaculture threatens the existence of wetlands in Bangladesh
Get PDFDespite positive role of aquaculture in food production, the practice may impact the environment negatively and it is difficult to quantify the loss. In this study, we assessed land use changes in four important wetlands (Hardoho Beel, Angrar Beel, Shaoil Beel and Gopalpur Beel) of Bangladesh through analysis of historical satellite images (1990 – 2020) to show how expansion of aquaculture activities threatens the existence of freshwater wetlands. Since 1990, the water area of all four wetlands decreased significantly over time (all p < 0.001). Mean yearly loss of 47.9 ± 79.3 ha, 99.2 ± 185.5 ha, 51.2 ± 61.9 ha and 2.6 ± 4.7 ha were recorded for Hardoho Beel, Angrar Beel, Shaoil Beel and Gopalpur Beel respectively. A decreasing trend in wetland area was recorded in all wetlands, primarily due to excavation of aquaculture ponds. In 2020, aquaculture ponds represented 72% of the core wetland areas. Two wetlands (Hardoho and Gopalpur) were almost totally lost and converted to aquaculture ponds and agricultural lands. This study concludes that the existence of freshwater wetlands in Bangladesh is at stake and recommends further studies to determine its impacts on people's livelihood and biodiversity
Feasibility of using sailfin catfish meal as an alternative to commercial fishmeal in the diets of juvenile guppy (Poecilia reticulata)
Get PDFA six weeks feeding trial was conducted to elucidate the effect of fishmeal produced from sailfin catfish (SCM) by replacing imported commercial fishmeal (FM) in the diet of Poecilia reticulata to reduce the cost of feed. Twenty one days old guppy fry (1.99±0.09 cm; 0.07±0.02 g) were fed four diets using different levels of SCM; control diet (CD; 0% SCM), 10SCM (10% SCM), 20SCM (20% SCM) and 30SCM (30% SCM). SCM contained higher protein content (69.5%) compared to FM (61%). Final body weight, %ADG, %SGR or FCR (1.77±0.16 – 2.21±0.26) and food consumption (9.3±0.1 – 9.45±0.5) did not influence by inclusion of SCM. Survival (>80%) did not influence by the type and quantity of fishmeal inclusion. Moreover, significantly higher profit index for 30SCM (8.94±1.43) and 20SCM (7.88±4.23) was recorded than CD (5.17±4.43) which contained imported, expensive FM. Overall, the present study revealed that commercial fishmeal can be fully replaced by SCM in the diets of juvenile guppy without any adverse effects on their growth. Therefore, producing fishmeal using sailfin catfish, which is an invasive species in reservoirs in Sri Lanka and an underutilized source, will be a feasible method to overcome the invasive problem
Induced spawning of African catfish (Clarias gariepinus) using goat (Capra aegagrushircus) and pig (Sus scrofa domesticus) pituitary extracts
Get PDFConcerns relating to cost and availability have directed traditional farmers to expand options on the induced spawning of fish for viable production of seeds. The study was conducted to examine the potential of using pituitary extracts (PE) from goat (Capra aegagrushircus) and pig (Sus scrofa domesticus) on the induced spawning of African catfish (Clarias gariepinus). Pituitary extract of African catfish using 4 mgkg–1 body weight dosage (control) and PE from goat and pig using 4 mgkg–1 and 200 mgkg–1 body weight dosages were single intramuscularly injected to female breeders. Utilisation of goat and pig PE has successfully induced the spawning of African catfish. All female breeders attained ovulation within 10-12 h which is under the prescribed latency period. Total number of eggs spawned ranged from 36200-67600. The three PE used attained comparable result in terms of relative fecundity. Fertilisation rate revealed that PE from goat at 4 mgkg–1 dosage attained similar result to that of control treatment. Hatching period occurred within 24–36 h and goat PE using both dosages gave the highest results in hatching rate. The current study provides preliminary information on the success of using PE from goat and pig for the induced spawning of African catfish
Study on proximate composition of four seaweeds from Kilinochchi and Kalpitiya area of Sri Lanka
Get PDFSome of the representatives from edible seaweeds (Gracilaria verrucosa, Gracilaria corticata, Turbinaria ornate, Sargassum polycystum) from Kilinochchi and Kalpitiya in Sri Lanka were investigated for proximate composition (moisture, protein, lipid and ash content). The proximate composition was significantly (p < 0.001) different across seaweed species. In this regard, moisture content (mean ± SD) varied from 76.33 ± 0.0% in T. ornata to 89.78 ± 0.6% in G. corticata. The S. polycystum presented the highest fat content (1.94 ± 0.5%); whereas, G. corticata showed the highest protein level (21.66 ± 1.1%). Fat content was low in T. ornata (0.37 ± 0.2%) and S. polycystum (1.94 ± 0.5%) while protein content was low in other three species. Also G. verrucosa and G. corticata had higher ash content (44.34 ± 3.8% and 44.34 ± 3.8% respectively) than other seaweed species. The variation in proximate composition was high among species and would be a healthy addition to normal diets
Comparative account on the length-weight and length-length relationships and condition factor of six cyprinid fishes from Dal Lake, Kashmir
Get PDFFish landings are routinely measured for length and weight to study fish bioecology, which provide important information about biomass, population dynamics and condition of fish. The current study describes the length-weight relationships (LWRs) and length-length relationships (LLRs) of six fish species (Cyprinus carpio, Carassius carassius, Schizothorax niger, S. curvifrons, Crossocheilus diplochilus and Pethia conchonius) based on seasonal fish sampling from the Dal Lake during September 2019 to August 2020. The estimated LWRs and LLRs were highly significant (p < 0.05) with high coefficient of determination r2 and the estimated b values ranged from 2.50 to 3.55. The estimated b values revealed negative allometric growth of fish species except P. conchonius which possesses positive allometric growth. The mean value of condition factor for C. carpio, C. carassius, S. niger, S. curvifrons, C. diplochilus and P. conchonius were 1.43±0.25, 1.55±0.24, 0.86±0.14, 0.80±0.13, 1.21±0.17 and 1.64±0.34 respectively and it varied significantly among these fish species (ANOVA: p < 0.05). The study shows LWRs, LLRs and current condition of some forage fish species viz., C. carassius, C. diplochilus and P. conchonius as well as invasive C. carpio and local Schizothorax species from the Dal Lake, all possessing economic and conservation significance
Development and characterisation of cooked inlaid sausages with fillet and mechanically separated meat of Nile tilapia (Oreochromis niloticus)
Get PDFThe limited consumption of fish is due to a limited availability of products based on this type of meat. Therefore, innovation and development of products that meet consumers’ preferences are essential. The aim of this work was to develop and characterize cooked inlaid sausages prepared with fillet and mechanically separated Nile tilapia (Oreochromis niloticus) meat (MSM). Three sausages types were considered, F1 (100% MSM), F2 (50% MSM, 50% fillet) and F3 (25% MSM, 75% fillet). Microbiological quality of the raw materials and products obtained were within the standard limits. F1 had the lowest protein (34.68%) and the highest lipid (2.88%) contents. F1 and F2 had the highest luminosity L*, which was related to the MSM composition, as the L* was higher as the percentage of MSM increased in the formulation. The shear strength was higher for F2 (18.55 N) and lower for F1 (6.43 N) and differed among sausages types. The F2 sausages presented a better acceptability regarding the sensory attributes evaluated, with acceptation indexes of 88.00, 85.55, and 84.66% for flavour, texture, and odour respectively. This finding indicates that this formulation would be very well accepted in the market if available for commercialisation
Traditional fish processing in Odisha, India
Get PDFThe present study documents the traditional fish drying techniques used by the fisher folk communities of Bhadrak district, Odisha, India. Information on local knowledge and the use of different fish drying methods within the study area was collected from 72 fisher folk through semi-structured questionnaires, free interviews, informal conversations and direct observations. The results showed that sun drying was the most extensively used method for fish preservation. About 19.4% of the informants preferred to spread the fishes directly on earth, 34.8% on the mat, 5.5% on palm leaves, 29.2% over bamboo bars and 11.2% followed interlocking of snouts/jaws on bamboo sticks. Almost all the fish drying devices are handmade with bamboo, wooden pole and sometimes nylon threads following traditional technologies. The quality of the dry fish could be improved by educating fishermen on hygiene, sanitation, use of good water quality and raw materials for processing. In this context, the low-cost solar dryer can be constructed by using locally available materials, thus preventing contamination and dependence on weather conditions. The dry fish production can play a crucial role in socio-economic upliftment, employment generation and poverty alleviation particularly to women as they depend on it directly for their livelihoods
Length-weight relationship, growth pattern and condition factor of four indigenous cypriniform Schizothorax species from Vishav Stream of Kashmir Himalaya, India
Get PDFThe indigenous Schizothorax spp. in the valley of Kashmir are facing constant threats and decline in their overall population. The current aim was to analyse the comparative length-weight relationship (LWRs) and condition factor (K) of 350 specimens belonging to four Schizothorax spp. (S. plagiostomus, S. esocinus, S. labiatus and S. curvifrons) from the Vishav Stream of Kashmir Himalaya, India. The fish specimens were sampled for a period of one year from April 2018 to March 2019. The results revealed that the growth coefficient ‘b’ in all the four Schizothorax spp. was found very close to 3, indicating an isometric growth pattern. No significant difference in the ‘b’ values of four Schizothorax spp. was found when compared with the isometric value (t-test: p > 0.05). The mean value of the ‘K’ for S. plagiostomus, S. esocinus, S. curvifrons and for S. labiatus were 0.81 ± 0.07, 0.80 ± 0.08, 0.85 ± 0.08 and 0.88 ± 0.12 respectively. The mean condition factor did not vary across four species (ANOVA: p > 0.05). The present findings could serve as baseline information for the management, stock assessment and future studies of indigenous capture fishery resources of the Vishav Stream and other similar habitats
Phenotypic characterization, genetic analysis and antibiotic sensitivity of Aeromonas hydrophila isolates causing dropsy in cultured Labeo rohita from Punjab, Pakistan
Get PDFMotile Aeromonas septicemia (MAS) is a common freshwater fish disease and major threat to the aquaculture in Pakistan. The present study was carried out on suspected fish samples to isolate and characterize local strains of Aeromonas hydrophila, a key pathogen responsible for the said disease in aquacultured fishes. A total of ninety suspected fish specimens were collected from fish farms in Kasur, Okara and Gujranwala districts of Punjab, Pakistan from June 2018 to April 2019. The specimens were processed and A. hydrophila strains were isolated. The primary identification of sixty seven isolates were verified by colony morphology, microscopy and phenotypic characterization with ten biochemical reactions. The A. hydrophila strains of test samples were molecularly characterized by polymerase chain reaction (PCR) using 16S rRNA at desired size of 356bp. The PCR amplified product was subjected to DNA sequencing and phylogenetic analysis showed homology with related strains of Aeromonas spp. By antibiotic sensitivity test, the isolates were checked for nine antibiotics in which the pathogen was sensitive to four and resistant to five drugs. Results of genetic analysis confirmed strains as A. hydrophila which are useful to take preventive measures against the said disease