Ichthyofauna assemblage and their spatiotemporal distribution: a case study in Asura beel of Dinajpur, Bangladesh

Abstract

Ichthyofauna diversity acts as a bio-indicator and is playing a significant role in the sustainability of an aquatic environment. The present study explores the ichthyofauna assemblage in one of the largest wetlands of Bangladesh known as Asura beel located in Dinajpur district. Fortnightly fish samplings were done from November 2017 to October 2018 considering three seasons as winter,summer, and rainy. Fish biodiversity was assessed with their threatened status and analyzed seasonal abundance with the diversity indices. Findings revealed a total of 35 identified species of fish belonging to 7 orders, 17 families, and 26 genera. According to IUCN- Bangladesh 2015, the current research recorded 6 fish species as vulnerable (17%). While only 1 species is data deficient (3%), 6 species are endangered (17%), and the other 22 species are not threatened (63%). Among the fish species, Amblypharyngodon mola of Cypriniformes order contributed the highest abundance (12%). On the contrary, Ostreobrama cotio and Macrognathus armatus both represented the lowest abundance by contributing 0.35%. The survey also reported that the seasonal diversity indices and richness values did not vary significantly according to seasons although the number of catches was found higher in the winter season followedby summer and rainy seasons.

Freshwater icthyo-faunal checklist of Roktodaho Beel in Bangladesh: Threats and conservation

“…133Khanom et al (2018) recorded a similar result in dominancy of orders in the Uthrail beel of Naogaon, where Cypriniformes was recorded as the dominant order, contributing 40.62%, and the rest 7 orders, Perciformes, Siluriformes, Synbranchiformes, Channiformes, Beloniformes, Tetraodontiformes, and Osteoglossiformes, contributing 26.31%, 12.4%, 9.77%, 7.59%, 2.90%, 0.22%, 0.22%, and 0.10%, respectively. Many other researchers(Ferdoushi et al, 2022;Kamrujjaman & Halder, 2022;Pandit et al, 2021 Pandit et al, , 2023aMia et al, 2017) also got similar results…”

“…A total of 36 species of wild ichthyofauna belonging to eight orders and 19 families were found in this beel (Table 1). Many more research studies have had such a pleasant stay since gauging the fish biodiversity in multiple wetlands in Bangladesh (Kamrujjaman and Halder, 2022;Ferdoushi et al, 2022;Khanom et al, 2018;Hossain et al, 2021;Mia et al, 2017;Suravi et al, 2017;Talukder et al, 2021). Ehshan and Bhuiyan (2014) found 46 species of fish, of which eight were exotic.…”

“…This indicates that the diversity of fish is declining compared to previous years. Ferdoushi et al (2022) recorded 35 species of fish belonging to 7 orders and 17 families in the Ashura beel of Dinajpur; Kamrujjaman and Halder (2022) reported a total of 34 species under 24 genera, 16 families, and 7 orders from the Bahadurpur beel of Madaripur district; Khanom et al (2018) reported 28 fish species under 8 orders and 16 families from the Uthrail beel of Naogaon district. The above-mentioned observations are lower than those of the present expedition.…”

“…Participants were questioned about potential dangers to the Roktodaho beel's array of fish throughout the data gathering process. Wide-ranging menaces were offered, including inadequate water flow, water contamination from rice mills, ash, dredging, trapping of fry and brood fish, haphazard drilling and deposits, faulty drainage and sluice gates, failure to establish legitimate beel management techniques for fish sanctuaries, use of herbicides and pesticides, and natural phenomena like drought, siltation, and water diversion, as well as irresponsible fishing practices (overexploitation, brood and juvenile fish exploitation According to many studies (Khanom et al, 2018;Ferdoushi et al, 2022;Pandit et al, 2021Pandit et al, , 2023aMia et al, 2017;Suravi et al, 2017), these factors are also thought to be contributing to the loss of fish variety in different regions of Bangladesh. The present research makes a number of recommendations on the basis of the research and firsthand knowledge for the protection and improved control of the fishery resources of the Roktodaho beel.…”