STUDY ON FACTORS AFFECTING THE WETLAND BIODIVERSITY IN THE HAOR REGION OF BANGLADESH

Abstract

The study was conducted to identify the factors affecting wetland fish biodiversity in Soma Nadi Jalmohal under Derai upazila and Dekhar Haor under Dakshin Sunamganj upazila in Sunamganj district for a period of 11 months from June 2013 to April 2014. The study was done by questionnaire interviews (QI) of fishers, focus group discussions (FGD), key informant interviews (KII) and secondary data collection. During the study period, a total of 84 fish species under 30 families were recorded where 65 species under 23 families were found in the study areas and 19 species disappeared within 10 years. The species availability status was remarked in four categories and obtained as 26 species commonly available, 18 moderately available, 21 rarely available and 19 species are not available. Among available 65 fish species, 9 species of carps, 16 species catfishes, 10 species of barbs and minnows, 1 species of clupeid, 4 species of snakeheads, 4 species of eels, 11 species of perches, 1 species of featherback, 3 species of loaches and other miscellaneous 6 species including 3 species of prawns were found. The highest abundance of fishes was catfish (24.62%). Highest abundance of commonly available 26 species was found in October to January and lowest species abundance was observed in April to June. Among 54 threatened fish species listed by IUCN (2000), about 37 species were found 10 years ago in the study areas but only 24 were found during the study period. It is revealed that there has been gradual reduction of the fish diversity in the haor areas that is from the earlier 84 species to present 65 species in the Dekhar Haor (22.62% declined) and 56 species in the Soma Nadi Jalmohal (33.33% declined). Average fish catch per fisherman per day was reduced from 8.35kg to 1.4kg in the Dekhar Haor and 6.7kg to 1.445kg in the Soma Nadi Jalmohal within 10 years. Combined effects of some factors are responsible for the loss of fish biodiversity. Major factors affecting fish biodiversity were grouped into four categories such as manmade factors, environmental factors, social factors and policy issues. Majority of the respondents agreed that two manmade factors namely fishing by complete dewatering of wetlands and overfishing were mainly responsible for loss of fish biodiversity in the haor region. During the survey, 91.25% respondents opined water depth reduction as the main environmental factor followed by siltation and sedimentation (88.75%). The respondents (72.5%) cited that the first and foremost social factor was private land ownership in the haor basin and the second social factor was agricultural cropping pattern. Among policy issues, a lot of respondents (82.5%) identified that leasing system was responsible for fish biodiversity degradation in the Dekhar Haor but only 27.5% fishermen from Soma Nadi Jalmohal area explained it as problematic factor for fish biodiversity. Community based fisheries management, fishing gears maintenance, sanctuary establishment and management, afforestation, implementation of fishing acts and regulations, stocking of fish fingerling in the open waters, dredging of beels and raising public awareness can play great role in conserving fish biodiversity. It can be concluded that factors identified in the present study need to be addressed to conserve and enhance fish biodiversity in the haor region of Bangladesh.