Abstract
Haor, an important part of wetland ecosystem plays enormous role in supply of abundant quantities of inland fish, generation of income and rural employment, foreign currency earning and maintenance of stable climatic condition in Bangladesh. Due to various reasons, aquatic biodiversity in the haor system are declining at an alarming rate. Considering the tremendous biological and economic importance of haors, the present study was undertaken in 4 selected beels such as, Rupaboi beel, Rowa beel, Ballardubi beel and Tekunna beel under Tanguar haor system in Sunamgonj district during the period from April 2014 through March 2016 to determine the (i) present status of fish biodiversity in terms of qualitative and quantitative representation of available fishes, and (ii) to determine cost and return from fishery activities in the selected beels. A survey questionnaire was developed, pre-tested and finally modified to fulfill the research objectives. The data were collected from the concerned beels twice a month by using the semi- structured questionnaire. The collected data were scrutinized, carefully examined, tabulated in a master sheet and subjected to statistical analysis. A total of 91 species of fishes belonging to 29 families with 54 genera were recorded from the studied beels. Shanon-Weiner diversity index was 3.281 in Ballardubi beel, 3.259 in Tekunna beel, 3.256 in Rowa beel and 3.136 in Rupaboi beel. All the studied beels were rich in terms of species occurrence and abundances. Among the 15 selected common group guilds, catfish (19.25 25.74%) was the most dominant group successively followed by Barb (18.44 - 20.04%), Carps (13.67 - 15.13%), Perch (6.08 - 12.33%), Minnows (6.53 - 8.89%), Eels (6.32 - 7.55%) and Prawns (2.85 - 4.17%) in all the studied beels. Surface feeders accounted for 45.61-56.03%, column feeders 4.04- 5.20% and bottom feeders 38.77 - 49.36%, to the total fish yield in the surveyed beels. Rupaboi beel, Rowa beel, Ballardubi beel and Tekunna beel sustained moderate to rich level of species diversity. Among the 29 families, Cyprinidae secured the top most position in respect of number of genera, species and total fishery yield. Cyprinidae formed the bulk of the total fish yield in all the studied beels, yielding 40.92% in Rupaboi beel, 43.76% in Rowa beel, 38.63 % in Ballardubi beel and 40.25% in Tekunna beel. Siluridae was next to Cyprinidae in term of numerical and quantitative representation. This family comprised of 9.17% of the total fish production in Rupaboi beel, 11.00% in Rowa beel, 12.65% in Ballardubi beel and 10.18% in Tekunna beel, respectively. Mean fish yield in Rupaboi beel, Rowa beel, Ballardubi beel and Tekunna beel stood at 517kg, 642kg, 675kg and 540kg/ha., respectively with per hectare net return of BDT 77236, BDT 92726, BDT 92778 and BDT 75566 respectively. The present study provided important information about the present status of fish biodiversity in Tanguar haor. Further studies should be conducted over a much longer period of time to precisely determine the holistic picture of aquatic biodiversity with a view to adopt appropriate conservation and management strategies to obtain sustainable fish yield from the haor system.