Impacts of zoning management of coastal ecosystem for three different activities: Reserve-fishing-ecotourism Prosenjit Paul, T.K. Kar, Kanisha Pujaru Ecological Informatics, 2020 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, Abhijit Ghorai Communications in Nonlinear Science and Numerical Simulation, 2018 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, T.K. Kar Ecological Modelling, 2016 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, Abhijit Ghorai Ecological Modelling, 2016 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.