This research aimed to assess the fish biodiversity and present status of the Dholai river in Companigonj Upazila under Sylhet district. A semi-structured questionnaire survey was used to gather the relevant information from 64 fishers from November 2019 to April 2020. This research identified 56 fish species under 21 families and ten orders. The most dominant order was Cypriniformes 32.14%, following Siluriformes 28.57%, Perciformes 14.28%, Channiformes 7.14%, Synbranchiformes 5.36%. The species availability status was observed in four categories and achieved as 17 species of commonly available (30.36%), 14 species of moderately available (25%), 17 species of less available (30.36%), and eight species of fishes were rarely found available (14.28%). A total number of five nets, one trap, one hook, and a line were recorded. The peak amount of mean Catch per Unit effort (CPUE) in the current jal was 3.67±1.50 kg/day, and the lowest was in borshi at 0.09±0.01kg/day. The highest diversity index value was 2.55 in January, and the lowest was 1.21 in April, with a mean value of 1.98±0.05. The peak richness index value was 2.76 in January, and the lowest was 1.79 in April, with a mean value of 2.36±0.1. The peak evenness value was 0.73 in January, and the lowest value was 0.41 in April, with the mean evenness value 0.61±0.05. The peck amount of fish production was in January as 478±70 kg/day, and less value was in March at 109±12 kg/day. The local fishermen identified several threats to fish biodiversity, fish habitat, and fish production of the Dholai river. The establishment of the fish sanctuary, control of river pollution, minimizing exploitation of sand and rock, conservation of angling gears ever, and maintaining fisheries rules and regulations will be effective for the conservation of fish biodiversity of the Dholai River.

Keywords: Fish biodiversity, Assessment, Dholai river, Bangladesh

The study investigated biodiversity, and the present status of the Teesta River fishery in Rangpur and Nilphamari district, Bangladesh, from November 2018 through October 2019. Questionnaire Interviews and Focus Group Discussions with Key Informant Interviews (KII) and a catch assessment survey were carried out in the study. A total of 45 fish species were identified under 17 families and ten olders. Fishes were categorized as commonly available (24.44%), moderately available (26.66%), less available (22.22%), and rarely available (26.66%). A total of 8 fishing gear were identified. The highest and lowest level of gear efficiency was recorded from Gill net and Dhoar (Fish trap) in May and June as 0.501 kg and 0.000209 kg, respectively. In October, all gear’s maximum average gear efficiency (1.039 kg) was recorded, and the minimum average gear efficiency (0.309 kg) was recorded in June. Shannon-Weaver diversity index (H’) was found to range from 1.11 to 2.42. Highest Margalef Species Richness (d) (3.24) was in April and the lowest (1.86) was in September. The highest Pielou’s Evenness Index (J’) (0.78) was documented in January, and the lowest (0.36) in August. The highest fish production was in April (592±65.30 kg/day), and the lowest in July (112±12.24 kg/day). Significant threats to fish biodiversity, habitat, and overall fish production of the Teesta River were identified. However, the establishment of the sanctuary, control of pollution, maintenance of fishing gear, and the implementation of the fish act is necessary for the conservation of fish biodiversity of this River.

Keywords: Fish biodiversity, abundance, CPUE, threats, Teesta River

Degradation of fish diversity in the freshwater habitats, especially the rivers of Bangladesh, has become a major concern in recent years. Therefore, this study was conducted in the Gurukchi River of Gowainghat sub-district in the Sylhet district of Bangladesh between March 2018 and February 2019 to assess the availability and biodiversity of fish species with conservation status, and population trends, and threats. Data were collected on a monthly basis by direct catch observation and field surveys as focus group discussions and personal interviews of different types of stakeholders. A total of 55 indigenous and two exotic fish species belonging to 9 orders, 22 families, and 42 genera were identified. Cypriniformes was the dominant order, comprising 40.35% of the total documented fish species, whereas Cyprinidae was found as the richest family (33.33%). A total of 10 threatened fish species (18.18%) were found in the study area where 5 species (9.09%) were endangered and five species (9.09%) were vulnerable. Notably, four globally threatened fish species such as Cirrhinus cirrhosus, Channa orientalis, Cyprinus carpio, and Wallago attu were available in the river. Among the identified native fish species, 52.73% of species showed decreasing population trends at the national level. Considering availability, the maximum fish species was rarely available (29.82%), followed by commonly available (28.07%), moderately available (22.81%), and abundantly available (19.30%). The main drivers affecting the river’s fish diversity were identified as indiscriminately overfishing, followed by dewatering fishing, dewatering for irrigation purposes, natural drought in the winter season, use of banned fishing gears, and katha fishing method. However, measures like the establishment and management of fish sanctuaries, creating alternate livelihood options for fishers, and building public awareness about fishing laws and regulations could be helpful in conserving the fish biodiversity of the Gurukchi River.

Keywords: Fish biodiversity, Availability status, Drivers, IUCN, Conservation.