Journal of Fisheries (University of Rajshahi)
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Sinusoidal growth, recruitment, mortality, yield-per-recruit analysis of Buried fan scallop Mimachlamys funebris (Reeve, 1853) and their implications for mariculture
Get PDFThis study described the growth, mortality, recruitment pattern and exploitation rate of the Buried fan scallop (Mimachlamys funebris) in Asid Gulf, Philippines. Monthly length-frequency data (N=3988) from April 2018 to March 2019 were used to examine population parameters using FISAT II. Two estimates of natural mortalities were used to compare variability of limit exploitation rates. Modelling through the oscillating von Bertalanffy growth function revealed that the species is fast growing (K=1.1 year–1) attaining SH∞ of 10.5 cm. Adequacy in the use of the sinusoidal version of the growth formula hinges on the mean annual temperature difference reported in the gulf to be 2°C. Recruitment pattern was continuous and bimodal throughout the year with two high pulses in April–May and September consistent with the reproductive seasonality reported for congeneric species. Fishing mortality coefficients (4.26 and 4.82 year–1) were higher than the natural mortality coefficients (0.543 and 1.1 year–1). Yield and biomass-per-recruit analysis showed that the current exploitation rates are 112% (Ecurr1 = 0.90) and 92% (Ecurr2 = 0.80) higher than the biological reference points adopted for the study particularly E50. These results demonstrate that M. funebris stock is overexploited, which necessitates effective management measures including mariculture
Feed intake, nutrient digestibility and nutrient retention in Atlantic salmon (Salmo salar L.) fed diets with different physical pellet quality
Get PDFThree feeds with different physical pellet quality but the same formulation were fed to Atlantic salmon for 97 days. Pellet quality was measured as bulk density, durability, fat leakage, hardness, water stability and porosity. The largest difference among the feeds was measured in hardness (201, 236 and 86 Newton for Diet 1, Diet 2 and Diet 3 respectively). The relative feed intake was highest in salmon fed Diet 2 and Diet 3 with no effects of pellet hardness. Growth and feed efficiency ratio were similar among all fish. The apparent digestibility of energy, dry matter, nitrogen and lipid was similar for all feeds, whereas the apparent digestibility of phosphorus and zinc was the lowest in Diet 3. Retention of energy, lipid and nitrogen was also similar for all feeds. Salmon fed Diet 1 and Diet 3 retained more phosphorus than those fed Diet 2. An increased retention of the digested zinc was found in salmon fed Diet 3. This study concludes that physical pellet quality affects feed intake and improve utilisation of feed in salmon if optimised properly. Moreover, pellet hardness can be optimised in commercial scale without compromising feed intake as it has no influence on feed intake
Effect of carp species combination on production and economics of stinging catfish, Heteropneustes fossilis based polyculture in homestead ponds under drought prone area of Bangladesh
Get PDFAquaculture of homestead ponds under drought prone areas is climatically challenged by increased temperature and decreased water level. These ponds are potentials for farming of a short cycle aquaculture species like Heteropneustes fossilis with carps but lack of appropriate species combination is the major constraint for promotion of this technique. To address this problem, an experiment was carried out during July to December, 2019 to evaluate the production and economics of H. fossilis based polyculture under different carp species combinations in homestead ponds in Tanore of Rajshahi district, Bangladesh. Three different combination of carps were tested under three treatments as T1: Labeo rohita dominant carps (L. rohita 50%, Gibelion catla 25% and Hypophthalmichthys molitrix 25%); T2: G. catla dominant carps (L. rohita 25%, G. catla 50% and H. molitrix 25%); and T3: H. molitrix dominant carps (L. rohita 25%, G. catla 25% and H. molitrix 50%), each with three replications. Stocking densities were 123500 ha–1 for of H. fossilis was and 988 ha–1 for carps. Water quality was monitored monthly and found within acceptable range. T3 was found significantly (p < 0.05) better than other groups in terms of yield and cost benefit ratio
Water pollution effects of river Saraswati and Kunti on livelihood: a case study of fishermen communities in Tribeni and Kuntighat, Hooghly, West Bengal
Get PDFA prolific study was conducted to find out the impact of pollution on the socio-economic status of the fishermen community of Tribeni, Kuntighat - Hooghly, West Bengal, who depend on the rivers Saraswati, Kunti and Ganga for their livelihood. Analysis of important water quality parameters clearly reflects the pollution status of the rivers Saraswati and Kunti. Investigation was carried out by a previously tested questionnaire and personal interaction with 100 fishermen based on which the probable reasons of decline in fish diversity were drawn, which consequently adversely affected the economic conditions of fishermen. The investigation revealed a positive correlation between discharge of industrial effluents, in turn depleting the availability of fish food organisms and fish diversity and warning socioeconomic conditions of fishermen. Results clearly indicate proper steps should be taken by the policy makers towards restoration of water quality and thereby helping the vulnerable fishermen
Ligula intestinalis infection of Pseudorasbora parva in Hirfanlı Dam Lake, Kırşehir, Turkey
Get PDFLigula intestinalis was found during the parasitological investigations of Pseudorasbora parva specimens collected from Hirfanlı Dam Lake, Turkey. It was found that 8.78% of all specimens were infected with L. intestinalis including 17 female (3.8%) and 22 males (4.95%). It was determined that the length–weight relationship equivalents of infected individuals with population differed from those of non-infected individuals. The b value of the infected individuals was found to be lower than the b value of the non-infected individuals. It is thought that the results obtained in this study will be beneficial in preserving and improving the ecological potential of the lake
First records of sponge-dwelling shrimp Synalpheus coutierei Banner, 1953 (Crustacea: Decapoda) from the west coast of India
Get PDFThe occurrence of the two pairs of mature sponge dwelling shrimp Synalpheus coutierei Banner, 1953 is reported first time from the west coast in Gujarat, India. This species is previously reported from the east coast of India. The detailed morphological characteristic and distribution of the species are given in the paper
Behavioural differences between breeding and nonbreeding pairs of protandry monogamous false clown anemonefish Amphiprion ocellaris
Get PDFAnemonefishes are some of the most popular marine ornamental fishes. Due to the adverse impacts of commercial fishing on the wild populations of anemonefishes, a more suitable and efficient captive breeding programme must be promoted. In the wild, anemonefishes are protandrous sex-changing fish, but when two immature individuals with ambisexual gonads are raised together in captivity, the two differentiate directly into a male and a female, to form a breeding pair. However, not all the formed pairs spawn, explaining the great care required in captive breeding. This behaviour appears to be counter-adaptative, as anemonefish social groups form randomly in the wild, and such phenomenon would disturb their breeding success. This study evaluated the behavioural and physiological differences between breeding and nonbreeding pairs of false clown anemonefish Amphiprion ocellaris under captive conditions. Behavioural observations revealed that nonbreeding females monopolized the shelter provided, whereas breeding females allowed breeding males to use the shelter and the pair frequently stayed together in the shelter. Both nonbreeding and breeding females possessed mature ovarian tissue and similar level of plasma estradiol concentrations, but nonbreeding males had a smaller amount of testicular tissue and lower plasma 11-ketotestosterone levels compared to breeding males
Microstructures of barbels and bony plates of Satyrichthys laticeps (Actinopterygii: Peristediidae)
Get PDFBarbels are sensory-appendage near the mouth of many fishes including Cyprinidae, Ictaluridae and Peristediidae and commonly used for identification of the species. Similarly scales and bony plates of fishes also being used in taxonomic studies. Satyrichthys laticeps commonly called armoured searobins, is a deep-sea peristediid that distributed in the Indo-West Pacific region of the world. However, surface structures of has been unknown. The aim of this study is to reveal the microstructures of barbels and bony plates of S. laticeps, occurring in the Andaman Sea of Thailand, for the first time by using a scanning electron microscopy method. The chin barbels were characterised by a pebble-like surface whereas lip barbels resemble wooden texture. Taste bud-like organs were only visible in chin barbels. Bony plates from heads contained small semispheres around spine. In dorsolateral of posterior body, pits appeared at the apices, and semispherical buds were present in the middle and basal parts of tubercles. The study results may be important in understanding the physiology in peristediid fish
Note on occurrence of Lutke’s halfbeak Hemiramphus lutkei Valenciennes, 1847 (Beloniformes: Hemiramphidae), along Odisha Coast
Get PDFThe paper reports occurrence of Lutke’s halfbeak Hemiramphus lutkei Valenciennes, 1847, for the first time from the coastal waters of Odisha coast, India. This report confirms the occurrence of this species form an extended geographical range along the east coast of India and will be helpful in further study of its biology, zoogeography and taxonomic status of the family Hemiramphidae
Multiplex-PCR protocol development for rapid screening of white spot syndrome virus (WSSV) in shrimp
Get PDFThis study was aimed to develop a faster single step multiplex PCR protocol for the simultaneous detection of white spot syndrome virus (WSSV) with its host (i.e. shrimp) as internal positive control. To do so, four combinations of primer were tested (I. 16S rRNA+Lo F1R1; II. 16S rRNA+Lo F2R2; III. 16S rRNA+Lo F1R2; IV. 16S rRNA+Lo F2R1) which were selected based on two pairs of WSSV specific primer (Lo F1R1 and Lo F2R2) and one pair of shrimp specific primer (16S rRNA). DNA extracted from WSSV infected shrimp were amplified by PCR in a single tube using each of the primer combinations and the thermal cycling conditions as well as reagent compositions were optimized. All the primer combinations yielded their expected band sizes with stronger band resolution intensity that indicated the development of four multiplex PCR protocols. The developed multiplex protocols reduced the chance of cross contamination and these were found to be faster, single step and unique with less effort and resource use. Considering sensitivity and specificity, among the protocols, we suggested the protocols based on 16S rRNA+Lo F1R1 and/or 16S rRNA+Lo F2R2 primer combinations for rapid and routine screening of WSSV in shrimp PL, juvenile and adult