Insights of under-water trophic interaction: A scenario in Chilika through the lens of Ecopath

Abstract

Abstract Tropical ecosystems show tortuous trophic interaction/network for the ease flow of energy or matter among its components. Being one of the fundamental principles of ecology, the trophic interaction narrates the overview of feeding strategies, food habits of inhabitants or feeding patterns, food items of predators, and the ecological roles of the organisms in a particular ecosystem in terms of the prey-predator relationship. Ecological concepts like “keystone species”, “niche overlap” and “electivity or selection of diet” are part of it. In this investigation, the feeding interaction of the Chilika lagoon ecosystem has been appraised. Chilika lagoon is a well-known tropical ecosystem having a complex food network system of various flora and fauna including more than 200 species of finfish and shellfish. In this study, the “keystone species of the Chilika lagoon ecosystem”, “niche overlap pattern” and the “electivity” through the mass balanced ecopath model were investigated. In the keystone analysis, three keystone indices (KS1, KS2 and KS3) were applied and the groups like Irrawaddy dolphin, croakers and perches were identified as keystone species by more than two keystone indices. Based on the niche overlap study, 108 pairs were identified. Groups like prawns and crabs were found as the most niche overlapping group among all the organisms and contributed about 13 and 11 number pairs among the 108 niche sharing pairs. Similarly, the electivity of the ecological groups was analysed, and interestingly, almost all groups were showing negative index values for detritus and macrophytes. Benthic groups like prawns and crabs play a crucial ecological role in the food web dynamics of Chilika lagoon. This study will be helpful to understand the complex interaction among different trophic groups of Chilika.