Uttar Dinajpur, India
Uttar Dinajpur, India

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Bagchi A.,North Bengal University | Jha P.,Raiganj Surendranath Mahavidyalaya
Reviews in Fisheries Science | Year: 2011

From the beginning of history, fish became an inseparable part of human life in India. Over the course of time, fish proved to be food of high nutritional value through empirical observation. The practice of casting a fish motif on coins or stone sculptures and seals, or using fish insignia in flags by ancient Hindu and Muslim rulers in medieval India, or the use of fish as a symbol of fortune and an object in literature and folksongs, prove that fish transcended the narrow limits of cultural segmentation. The establishment of cities with an ever-increasing population and changing food habits created an obvious demand for large-scale fish culture in the 20th century. Fish production from natural waterbodies trended downward during the later decades of the 20th century. Meanwhile, the technologies of induced breeding and polyculture virtually revolutionized the freshwater pisciculture sector over the last 50 years, and Indian fish production registered excellent growth—from 0.75 mt in 1950 to 6.3 mt in 2002. Hopefully, pisciculture may be part of the solution to the increasing need for food diversity and arresting the decline in per capita protein nutrition of the Indian populace in the years to come. © Taylor and Francis Group, LLC.


Goswami P.,North Bengal University | Mandal P.,North Bengal University | Jha P.,Raiganj Surendranath Mahavidyalaya | Misra T.,North Bengal University | Barat S.,North Bengal University
Journal of Agricultural Science and Technology | Year: 2013

Twenty spices were employed to preserve the cooked and uncooked fillet of Puntius sarana (Hamilton) and Puntius ticto (Hamilton). IC50 values of 2,2'-diphenyl-1- picrylhydrazyl (DPPH) based free radical scavenging activity ranged from 0.1123 μg ml-1 in turmeric to 13.035 μg ml-1 in roman coriander. Phenol content ranged from 0.365 μg g-1 in onion to 5.67 μg g-1 in clove. The raw and cooked fillets of P. sarana, and the cooked fillet of P. ticto, treated with garlic recorded the highest rates of thiobarbituric acid (TBA) reactivity (P< 0.05). For raw P. ticto, both the control and garlic treated fillet recorded higher rates of TBA reactivity (P< 0.05). Fillet of both fish species recorded higher TBA reactivity under raw condition, compared to cooked fillet. This condition was similar for the spice treated fillet. The exceptions were garlic, green and black cardamom, roman coriander and onion for P. sarana and garlic, cumin, field mustard, black pepper and poppy seed for P. ticto, where TBA reactivity was higher in cooked condition. It is recommended that spices with active phenolic antioxidants be used to inhibit the lipid oxidation in P. sarana and P. ticto. However, application of garlic extract for fillet preservation should be avoided until further documentation.


Sarwardi S.,Raiganj Surendranath Mahavidyalaya | Mandal P.K.,Visva Bharati | Ray S.,Visva Bharati University
BioSystems | Year: 2012

Gauss's competitive exclusive principle states that two competing species having analogous environment cannot usually occupy the same space at a time but in order to exploit their common environment in a different manner, they can co-exist only when they are active in different times. On the other hand, several studies on predators in various natural and laboratory situations have shown that competitive coexistence can result from predation in a way by resisting any one prey species from becoming sufficiently abundant to outcompete other species such that the predator makes the coexistence possible. It has also been shown that the use of refuges by a fraction of the prey population exerts a stabilizing effect in the interacting population dynamics. Further, the field surveys in the Sundarban mangrove ecosystem reveal that two detritivorous fishes, viz. Liza parsia and Liza tade (prey population) coexist in nature with the presence of the predator fish population, viz. Lates calcarifer by using refuges. In view of such observations in mind, a three-component model consisting of two prey and one predator population is considered in the present investigation with the inclusion of Holling type-II response function incorporating a constant proportion of prey refuge. The essential mathematical features of the present model have been analyzed thoroughly in terms of the local and the global stability and the bifurcations arising in some selected situations as well. The threshold values for some parameters indicating the feasibility and the stability conditions of some equilibria are also determined. The ranges of the significant parameters under which the system admits a Hopf bifurcation are investigated. The explicit formulae for determining the stability, direction and other properties of bifurcating periodic solutions are also derived with the use of both the normal form and the central manifold theory. Numerical illustrations are performed finally in order to validate the applicability of the model under consideration. © 2012 Elsevier Ireland Ltd. All rights reserved.


Sarwardi S.,Raiganj Surendranath Mahavidyalaya | Haque M.,University of Nottingham | Mandal P.K.,Visva Bharati
Nonlinear Dynamics | Year: 2012

A system of delay differential equation is proposed to account the effect of delay in the predator- prey model of interacting population. In this article, the modified ratio-dependent Bazykin model with delay in predator equation has been considered. The essential mathematical features of the proposed model are analyzed with the help of equilibria, local and global stability analysis, and bifurcation theory. The parametric space under which the system enters into a Hopf-bifurcation has been investigated. Global stability results are obtained by constructing suitable Lyapunov functions. We derive the explicit formulae for determining the stability, direction, and other properties of bifurcating periodic solutions by using normal form and central manifold theory. Using the global Hopf-bifurcation result of Wu (Trans. Am. Math. Soc., 350:4799-4838, 1998) for functional differential equations, the global existence of periodic solutions has been established. Our analytical findings are supported by numerical experiments. Biological implication of the analytical findings are discussed in the conclusion section. © Springer Science+Business Media B.V. 2011.


Sarwardi S.,Raiganj Surendranath Mahavidyalaya
Bio Systems | Year: 2012

Gauss's competitive exclusive principle states that two competing species having analogous environment cannot usually occupy the same space at a time but in order to exploit their common environment in a different manner, they can co-exist only when they are active in different times. On the other hand, several studies on predators in various natural and laboratory situations have shown that competitive coexistence can result from predation in a way by resisting any one prey species from becoming sufficiently abundant to outcompete other species such that the predator makes the coexistence possible. It has also been shown that the use of refuges by a fraction of the prey population exerts a stabilizing effect in the interacting population dynamics. Further, the field surveys in the Sundarban mangrove ecosystem reveal that two detritivorous fishes, viz. Liza parsia and Liza tade (prey population) coexist in nature with the presence of the predator fish population, viz. Lates calcarifer by using refuges. In view of such observations in mind, a three-component model consisting of two prey and one predator population is considered in the present investigation with the inclusion of Holling type-II response function incorporating a constant proportion of prey refuge. The essential mathematical features of the present model have been analyzed thoroughly in terms of the local and the global stability and the bifurcations arising in some selected situations as well. The threshold values for some parameters indicating the feasibility and the stability conditions of some equilibria are also determined. The ranges of the significant parameters under which the system admits a Hopf bifurcation are investigated. The explicit formulae for determining the stability, direction and other properties of bifurcating periodic solutions are also derived with the use of both the normal form and the central manifold theory. Numerical illustrations are performed finally in order to validate the applicability of the model under consideration. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.


Experiments were conducted to record mating behavior (Experiment 1) and offspring production (Experiment 2) in the guppy, Poecilia reticulata, stocked under different operational sex ratios. Male and female guppies were stocked in aquaria (Experiment 1) and in concrete tanks (Experiment 2) at sex ratios (male:female) of 2:1 (Treatment 1), 1:1 (Treatment 2), and 1:2 (Treatment 3). Courtship displays were significantly less in Treatment 3 (P<0.05). Sneak copulation was highest in Treatment 1 (P < 0.05). Time spent by the focal female on feeding was highest in Treatment 3 and lowest in Treatment 1 (P < 0.05). Offspring production per female, initial weight of offspring, and growth values recorded for the adult female fish were highest in Treatment 3 (P < 0.05). Weight and survival rate of offspring produced from each experiment was highest in Treatment 3 (P < 0.05). Treatment 3 appeared to be the most viable in terms of both quality and quantity of offspring produced. The results indicate a female biased sex ratio (adult male:female, 1:2) to be more effective than a male biased or an evenly matched sex ratio for enhanced offspring production in the guppy. © Taylor & Francis Group, LLC.


PubMed | Raiganj Surendranath Mahavidyalaya
Type: Journal Article | Journal: Bio Systems | Year: 2012

Gausss competitive exclusive principle states that two competing species having analogous environment cannot usually occupy the same space at a time but in order to exploit their common environment in a different manner, they can co-exist only when they are active in different times. On the other hand, several studies on predators in various natural and laboratory situations have shown that competitive coexistence can result from predation in a way by resisting any one prey species from becoming sufficiently abundant to outcompete other species such that the predator makes the coexistence possible. It has also been shown that the use of refuges by a fraction of the prey population exerts a stabilizing effect in the interacting population dynamics. Further, the field surveys in the Sundarban mangrove ecosystem reveal that two detritivorous fishes, viz. Liza parsia and Liza tade (prey population) coexist in nature with the presence of the predator fish population, viz. Lates calcarifer by using refuges. In view of such observations in mind, a three-component model consisting of two prey and one predator population is considered in the present investigation with the inclusion of Holling type-II response function incorporating a constant proportion of prey refuge. The essential mathematical features of the present model have been analyzed thoroughly in terms of the local and the global stability and the bifurcations arising in some selected situations as well. The threshold values for some parameters indicating the feasibility and the stability conditions of some equilibria are also determined. The ranges of the significant parameters under which the system admits a Hopf bifurcation are investigated. The explicit formulae for determining the stability, direction and other properties of bifurcating periodic solutions are also derived with the use of both the normal form and the central manifold theory. Numerical illustrations are performed finally in order to validate the applicability of the model under consideration.

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