Fish Production Patterns, Indigenous Fish Diversity, and Environmental Influences in a Tropical Floodplain Wetland: Implications for Livelihood and Nutrition

Small indigenous fish (SIF) production from wetlands provides nutritious food and supports the livelihood of the fishing community. The present study investigated the fish production trend, SIF diversity, and role of environmental and climatic parameters in Beledanga, a floodplain wetland in lower Ganges, through the sampling and collection of data from the local fishermen cooperative society. The fish catch composition in the wetland shifted after 2019, with the increased Ctenopharyngodon idella (grass carp) contribution from 11% to 17% due to the introduction of in situ seed-raising technology of an HDPE (high-density polyethylene) pen culture system. The fish fingerling stocking has a profound impact on fish production (R2 = 0.60, p = 0.007). During the study period, 19 species of SIF were recorded, with a higher abundance observed in the monsoon season. The naturally occurring SIF contributed 16% of the total fish catch, with the highest catch in 2011 (11,970 kg). Water pH and phosphate content are the two most important environmental parameters that influence SIF. The generalized additive model (GAM) indicated that the optimum annual rainfall for fish production in the wetland was between 750 and 1250 mm. The average annual fish production of 43,017 kg through stocking and SIF support the livelihood and nutritional security of the fishers. As the SIF showed a decreasing trend of production, habitat protection, scientific stocking, and in situ enclosure culture are recommended for sustainable enhancement of fish production and to conserve the SIF diversity.