Prosenjit Paul

Scopus Publications

Transient indicator of exploited communities at equilibrium in generalist predator–prey models
Esita Das, Prosenjit Paul, and T. K. Kar
Springer Science and Business Media LLC

Reactivity and recovery in an exploited one prey two predators system at equilibrium
Prosenjit Paul, Esita Das, and T. K. Kar
Springer Science and Business Media LLC

Reactivity in prey–predator models at equilibrium under selective harvesting efforts
Prosenjit Paul, T. K. Kar, and Esita Das
Springer Science and Business Media LLC

Relationship between multiple ecosystem services and sustainability in three species food chain
Kanisha Pujaru, T.K. Kar, and Prosenjit Paul
Elsevier BV

Impacts of zoning management of coastal ecosystem for three different activities: Reserve-fishing-ecotourism
Prosenjit Paul, T.K. Kar, and Kanisha Pujaru
Elsevier BV
Abstract Balancing the representation of marine ecosystems and threatened resources is critical for optimizing total rent (fishing+ecotourism), achieving the convention on sustainable use of resources. Comprehensive marine zoning provides a useful tool with which these essential concepts are addressed. A bioeconomic model is constructed, allowing three different aims to reserve, fishing, ecotourism, and total optimized rent, resource abundance, and the number of tourist changes. We provide ecological justification for the introduction of three different zones in the dynamic resource model. We obtain the conditions of optimizing total rent if the resource has no movement rate and fast movement rate among three different zones. Apart from the analytical results for the models under consideration, we perform extensive numerical simulations to construct the relevant, optimized benefit, resource abundance, and some tourists change diagrams. Our analytical and supportive numerical findings reveal that reserve is always good for fishery's sustainable management in the presence of fishing and ecotourism. Finally, we discuss the ecological implication of the current investigation in the conclusion section.

Impact of marine reserve on maximum sustainable yield in a traditional prey-predator system
Prosenjit Paul, T.K. Kar, and Abhijit Ghorai
Elsevier BV
Abstract Multispecies fisheries management requires managers to consider the impact of fishing activities on several species as fishing impacts both targeted and non-targeted species directly or indirectly in several ways. The intended goal of traditional fisheries management is to achieve maximum sustainable yield (MSY) from the targeted species, which on many occasions affect the targeted species as well as the entire ecosystem. Marine reserves are often acclaimed as the marine ecosystem management tool. Few attempts have been made to generalize the ecological effects of marine reserve on MSY policy. We examine here how MSY and population level in a prey-predator system are affected by the low, medium and high reserve size under different possible scenarios. Our simulation works shows that low reserve area, the value of MSY for prey exploitation is maximum when both prey and predator species have fast movement rate. For medium reserve size, our analysis revealed that the maximum value of MSY for prey exploitation is obtained when prey population has fast movement rate and predator population has slow movement rate. For high reserve area, the maximum value of MSY for prey’s exploitation is very low compared to the maximum value of MSY for prey’s exploitation in case of low and medium reserve. On the other hand, for low and medium reserve area, MSY for predator exploitation is maximum when both the species have fast movement rate.

Impacts of invasive species on the sustainable use of native exploited species
Prosenjit Paul and T.K. Kar
Elsevier BV
In recent years, the important challenging issues are biological invasions to biodiversity, overexploitation and extinction of several species. Invasive species often alter the workings of ecosystems around the globe. In the present research, our aim is to study the possible impacts of invasive species on the sustainable use of native exploited species. To address this issue, cleaning operation is introduced to protect biodiversity and recover stocks. It is found that presence of invasive species reduces the maximum sustainable yield (MSY) of native species. In case of prey–predator system, prey harvesting at MSY level causes the extinction of predator species, but extinction effort increases with the cleaning effort. It is also observed that when independent efforts are applied on both the prey and predator species, global maximum sustainable total yield (MSTY) exists and it increases as the cleaning effort increases. In all the cases it is found that appropriate cleaning effort may reduce the impacts of biological invasions on the sustainable use of resources.

Ecotourism and fishing in a common ground of two interacting species
Prosenjit Paul, T.K. Kar, and Abhijit Ghorai
Elsevier BV
This paper investigates some economic consequences of implementing ecotourism which is inhabited by two interacting stocks: a stock of prey (fish) and a stock of predator (marine mammals, e.g., whale, seals, shark, etc.). The prey species is targeted for commercial fishing while the predator species is not subject to fishing but is a potential basis to implement the eco-tourism. We specifically address two key issues. First, we examine the consequences of entrance fee on the total benefit (fishing+eco-tourism) depending on the sensitivity of the number of tourists to the predator abundance level. It is found that total benefit always increases with entrance fee until the entrance fee reaches its optimal value. Second, we examine the effects on interacting species from attempts to reach MSY in prey species. It is found that total benefit always higher than the benefit coming from fishing only even if the fishing is done at MSY level.

Impact of species enrichment and fishing mortality in three species food chain models
Prosenjit Paul, Bapan Ghosh, and T.K. Kar
Elsevier BV
Abstract In the present article, we consider two food chain models with three trophic levels: one is ‘prey–predator–top predator’ system where the top-predator consumes only the predator trophic level and the another one is ‘prey–predator–generalist predator’ system where the generalist-predator (top trophic level) consumes both the predator and the prey species. We examine the impacts of different levels of nutrient supply to the bottom species (prey) in both the models. We derive conditions when additional nutrient supply cannot bring the top trophic level to coexist in both the systems if the top trophic level is absent prior to nutrient supply. Once the three trophic levels are present prior to an additional nutrient supply, biomass of the predator trophic level reduces or even the predator trophic level goes to extinction in the ‘prey–predator–generalist predator’ system due to a massive amount of nutrient supply. We also explore the impacts of fishing mortality to achieve maximum sustainable yield (MSY) from individual trophic level. The most important conclusion is that harvesting the predator at MSY level is a sustainable fishing policy in ‘prey–predator–generalist predator’ system.

Extinction scenarios in exploited system: Combined and selective harvesting approaches
Bapan Ghosh, Prosenjit Paul, and T.K. Kar
Elsevier BV
Abstract This paper illustrates the effects of exploitation for yield maximization in prey–predator system where two predators are competing over same resource. Harvesting the prey (bottom trophic level) for yield maximization causes the extinction of the predators, but exploitation of either predator at MSY level becomes biologically sustainable policy. We show that harvesting multiple trophic levels including the prey species for total yield maximization may be sustainable under equal harvesting effort, but predator species goes to extinction under independent harvesting efforts. We also establish that neither predator goes to extinction if both predator trophic levels (i.e., excluding the prey species) are exploited under independent effort at maximum level; though either predator may be driven to extinction under combined harvesting effort.