Feeding and Breeding Biology of Amblypharyngodon mola – A Review

Amblypharyngodon mola is a popular food fish of Indian sub-continent due to its high nutritional value. Earlier many workers have carried out studies on feeding and breeding biology of this fish species but consolidated information on the same is not available. So, a survey of published literatures on the feeding and breeding biology of A. mola has been carried out to consolidate the available information.  Lacunae of information has been pointed out for further study mainly on age group wise variation in food preference and correlation of breeding periodicity with hydrological parameters and photoperiod

Length-weight relationship of Mystus tengara (Ham.-Buch., 1822), a freshwater catfish of Indian subcontinent

Length-weight relationship is the most commonly used analysis which has been used for several purposes in fisheries field among which estimation of weight from length is the most popular one. The present study has been performed to analyze the length-weight relationship of Mystus tengara, a freshwater catfish of Indian subcontinent. Total Length and Body Weight of the studied specimens have been observed to vary from 7.2-11.3 cm (male), 7.3-11.7 cm (female) and 3.43-13.63 g (male), 2.83-14.88 g (female). The calculated regression coefficient (b) values are 2.941, 3.119 and 3.071 for male, female and combined sex, respectively; thus depicting negative allometric growth for male; while positive allometric growth for female and combined sex of this fish species. The correlation coefficient values (0.94, 0.95 and 0.95 for male, female and combined sex, respectively) are suggesting a significant relationship between length and weight of the studied fish. The present study provides the first baseline information on the length weight relationship of M. tengara which will be beneficial for future management of this fish species

Tert-butyl N-{2-[N-(N,N′-dicyclohexylureidocarbonylethyl)carbamoyl]prop-2-yl}carbamate

The title compound, C25H44N4O5, exhibits a turn with the main chain reversing direction, held together by an intramolecular N-H⋯O hydrogen bond. In the urea fragment, a notable amide C-N bond between the carboxyl C and the tertiary N atom shows marked single-bond character [1.437 (2) Å]. The dihedral angle of the β-alanyl residue, centrally located in the turn, is gauche [69.2 (2)°]. The packing is mediated by two intermolecular hydrogen bonds and van der Waals contacts involving the methyl moieties and the cyclohexyl rings

Effect of differential duration of androgen treatment on growth of Nile tilapia under Indian condition

Little is known about the effect of differential duration of androgen treatment on growth performance of Oreochromis niloticus in India. In this study, 3 days old juveniles of tilapia were fed with 17α-methyltestosterone treated diet for three different duration regimes: 0 days (control), 30 days (30 days treatment) and 180 days (throughout treatment). After six months of culture, different growth parameters like body weight, length, depth, daily weight gain (DWG), specific growth rate (SGR) and proximate body composition were analyzed. The serum testosterone concentrations of the fish were measured from the 3rd month of culture. It was found that both the 30 days treated and throughout treated categories yielded significantly higher weight, length, depth, DWG, SGR and protein content compared to the control fish. But, there was no significant difference in growth parameters among the two hormone treated groups. Achievement of an optimum saturation level of hormone activity after the application of a particular titre of testosterone may attribute to such trend in growth pattern. The serum testosterone concentration of the 30 days treated fish at the end of culture period is similar to that of the control males. This can validate the human consumption of the 30 days treated tilapia rather than throughout treated ones that have ~2 times more testosterone concentration at the same time. Thus, dietary androgen treatment for the first month of culture followed by rearing with control diet can be regarded as the ideal method for sustainable augmented fish production in India

Comparative growth performance of mixed-sex and monosex Nile tilapia at various stocking densities during cage culture

Information related to impact of stocking density on growth performance of androgen-treated monosex Nile tilapia, Oreochromis niloticus during cage culture in West Bengal, India is limited. The aim of this study was to compare the growth potential of mixed-sex control and hormone-treated monosex tilapia at various stocking densities and to determine an ideal stocking density for cage culture of monosex fish. Mixed-sex control and 17α-methyltestosterone treated monosex tilapia were stocked separately in standing surface cages at different stocking densities (1, 5, 10, 15, 25, 50, 75 and 100 fish/m3). At the end of 5-month culture period, the highest growth was observed in the 50 fish/m3 groups for both the control and hormone treated categories. More over, the monosex androgen treated tilapia in each density class showed significantly higher (P-value < 0.05) weight, length and depth compared to mixed-sex fish in the corresponding density class. The survival rate of the fish did not alter significantly with hormone treatment but stocking density had significant effect (P-value < 0.05) on it. Thus, cage culture of hormone treated monosex tilapia at a density of 50 fish/m3 may be considered ideal for augmented production of the fish under Indian context

Vulnerability of the mosquito larvae to the guppies (Poecilia reticulata) in the presence of alternative preys

Background & objectives: The predatory potential of the larvivorous fishes can be affected by the presence of alternative preys. In the present study the predation pattern of the sewage dwelling Poecilia reticulata (Peters 1872) on the larvae of Culex quinquefasciatus Say 1823 (Diptera: Culicidae) was evaluated in the presence of alternative preys. Methods: The predation of Cx. quinquefasciatus larvae by different size groups of P. reticulata fishes was evaluated. In addition to this, the niche breadth (N) and diet breadth (B) were measured following Manly’s selectivity index (Si) as an indicator of variation of such predation pattern in the presence of alternative prey types, like chironomid larvae and tubificid worms.Results: The consumption of IV instar Cx. quinquefasciatus larvae by individual P. reticulata ranged between 65 and 84 in a 3 h feeding period and varied with the size of fish (F2, 33 = 34.91; p<0.001). The selectivity coefficient revealed a significantly low preference for the Cx. quinquefasciatus larvae (0.16, CL: 0.05 – 0.27; p< 0.05) compared to the chironomid larvae and tubificid worms, when all the three prey types were present. The niche breadth (N) and diet breadth (B) ranged from 0.77 to 0.92 and 0.69 to 0.93, respectively. The total consumption of all the prey types varied with the predator density, but the selectivity index for the mosquito larvae was significantly low in all the instances.Interpretation & conclusion: P. reticulata can consume a good number of mosquito larvae, with the consumption rate varying with the body size. P. reticulata fishes exhibit low preference for mosquito larvae as prey in the presence of alternative controphic preys like chironomid larvae and tubificid worms. Though establishment and sustenance of P. reticulata in new habitats will be favoured by the presence of alternative preys, but vulnerability of mosquito larvae may be reduced with availability of multiple preys in natural conditions

Indigenous ornamental fishes of west Bengal

Ornamental fishes are attractive colourful fishes of peaceful nature that are kept as pets in aquarium for recreation purpose. Ornamental fish keeping is the second most popular hobby next to photography. And the ornamental fish industry is one of the most booming one among the World; India having a good share of it. India is blessed with a great resource of different natural ornamental fishes. West Bengal is also sanctified with a wide range of indigenous ornamental fishes of biological as well as commercial importance. Due to lack of information and proper conservation strategy many of them are on the verge of extinction.&nbsp; In the present study, different rivers and water bodies of all the districts of West Bengal have been surveyed thoroughly for natural ornamental fishes. A total number of 70 indigenous ornamental fish species belonging to 45 genera, 30 families and 9 orders were collected and identified during the survey period. Among all the collected fishes order cypriniformes shows the maximum species variation, followed by perciformes and siluriformes. The study shows that a lot of the available ornamental ichthyofauna are endemic to some region and needed to be conserved. Among the fish specimen available many have a huge commercial value. But habitat destruction, unregulated fishing practice, water pollution, lack of proper awareness and introduction of exotic fishes are some potent reasons of declining fish population of this region

Occurrence and Antibiotic Susceptibility Among Coliform Bacteria Isolated From Sewage Exposed Fish.

Bacteriological contamination of muscles and digestive tract contents of Oreochromis sp. and Labeo sp. reared in a pond supplied with domestic sewage was enumerated followed by determination of resistance of thermotolerent coliforms for antibiotics. Numbers of bacteria in muscles and digestive tract contents of fish reflected their densities in water. Muscles of both the fish species contained high numbers of total coliforms (TC) and fecal coliforms (FC). Escherichia Coli (E. coli) were never recovered from the muscles but from the digestive tract contents of the fish. Ranking of the total and fecal coliform contamination levels showed a decrease in the order digestive tract contents> muscles (

Eutropiichthys vacha (Hamilton, 1822), a threatened fish of Indian subcontinent

Eutropiichthys vacha (Batchwa vacha) is a freshwater catfish species having high economic value. It is a very popular table fish among the consumers due to high nutritional value and taste. Just recently small specimens of this species have also made their entry in ornamental fish markets. Recently due to number of reasons, populations of this fish species are facing the threat of extinction. It has already been documented as Endangered in India and Critically Endangered in Bangladesh. The present report has been prepared to summarize the information available on different aspects of this threatened fish species as well as to point out the possible measures that should be considered for its conservation

A review on Labeo calbasu (Hamilton) with an emphasis on its conservation

Labeo calbasu is a freshwater fish species and is the most important carp species next to three Indian Major Carps Labeo rohita, Catla catla and Cirrhinus mrigala. It is a popular food fish and also is admired as a sport fish. Recently this fish species has also made its entry in ornamental fish markets of India and abroad. In last few years, the natural populations of this fish species has seriously declined due to over fishing and other anthropological reasons. In India it has been reported as Lower Risk near Threatened and in Bangladesh as endangered species. Earlier number of works has been conducted on different aspects of Labeo calbasu including food and feeding habit and reproductive biology. This report has been prepared with a view to sum up all those previously documented information along with pointing out the missing information further study of which will be beneficial for its fishery. Apart from this, it has been tried to note down some possible measures which should be considered for its conservation