Alcolyra, a new genus of leucosiid crab (Crustacea: Decapoda: Brachyura) from India

The identity of Philyra alcocki Kemp, 1915 (Leucosiidae), a species described from Chilika Lake, India is clarified. The redescription of lectotype male and examination of fresh material collected from Chilika Lake, Odisha state of India revealed that P. alcocki is significantly different morphologically from members of Philyra senso stricto and other allied genera in possessing two tuberculated rows on the branchial region of carapace, and a well-developed tubercle on male thoracic sternite 5 on either side of the sternopleonal cavity. Therefore, a new genus Alcolyra n. gen. is established herewith for the species.

ECONOMICS OF FISH PRODUCTION IN CHILIKA LAKE OF ODISHA

Objective-The objectives of the study are to examine the trend and pattern of cost, income and profit from Fish economy in Chilika Lake, to investigate the seasonality and pattern of revenue from tourism in Chilika Lake, to analyze the income and living standards of businessmen and their perception and to assess the developmental activities by Government of Odisha and Chilika Development Authority (CDA) to promote wetland services of Chilika. Methodology-The study is based on environmental impact on Chilika. Approximately 160 species of birds mostly of intercontinental migrant species and Irrawaddy dolphin, the lake is having immense tourism potential. Findings-Chilika as a wetland has a complex and fragile ecosystem unlike other water bodies. Chilika Lake has about 132 fishing villages and it is surrounded by around 273 villages. The population of the fishing villages is more than 0.15 million. Though the country earns foreign revenue by exporting spices fish, prawn, crab its cultivation on crop land is exerting negative impact on the nearby villages and therefore aims at conducting a survey on the socio economic conditions of people involved in fishing activity and the environmental impact of fish cultivation. KEYWORDS: Chilika, Crab, Ecosystem, Fishing, Local businessmen, prawn, Tourism, Wetland

Modeling the interaction of birds and small fish in a coastal lagoon

Coastal lagoons are high value productive and important systems for different projects. For example, aquaculture, fisheries and tourism are few of them. The quality of coastal waters in the ecosystems of lagoons can be greatly influenced by the growth of unwanted elements, e.g., excessive fisheries, tourism, etc. In this paper, a mathematical model is proposed and analysed to study the general and simplified form of an ecosystem of Chilika Lake, India. Chilika Lake (19°28′N–19°54′N and 85°06′E–85°36′E) is the largest wintering ground for migrating water fowl found anywhere on the Indian sub-continent. These migratory birds utilize the Chilika Lake for feeding, resting and breeding. The interaction of birds and small fish in the Chilika Lake is considered to be Leslie–Gower Holling type II. Since big fish are being sourced as income for local fishermen and the population of big fish is highly variable, and hence birds and small fishes are mainly the two types of biomass considered for this study. It must be noted that, in this study, we have considered the case of Chilika lake theoretically only and no practical data is collected for this study, and the name of Chilika is used only for better ecological understanding. Therefore, this theoretical study maybe linked to any such ecosystem. Their interaction is found mathematically, a two-dimensional continuous-time dynamical system modeling a simple predator–prey food chain. The dynamical system is represented in the form of two nonlinear coupled ordinary differential equation (ODE) systems. The main mathematical results are given in terms of boundedness of solutions, existence of equilibria, local and global stability of the coexisting interior point. An ecosystem in Indian coastal lagoons may suffer immediate environmental perturbations, such as depressions, tropical cyclones, earthquakes, epidemics, etc. To model such situations, the ODE model is further extended to a stochastic model driven by L e ́ $\check{d}{e}$ vy noise. The stochastic analysis includes the existence of the unique global solution, stability in mean, and extinction of the population. The proposed model is numerically simulated with the help of an assumed set of parameters for the possible pictorial behavior of the theoretical model. The proposed model may be used for planning purposes by using the data on meteorological and weather shocks such as heavy rainfall, heat-waves, cold-waves, depressions, tropical cyclones, earthquakes, etc. from India Meteorological Department (IMD).