Diversity of fishery resources and catch efficiency of fishing gears in Gorai River, Bangladesh

Kishor Kumar Tikadar,Mrityunjoy Kunda,Sabuj Kanti Mazumder

doi:10.1016/j.heliyon.2021.e08478

Kishor Kumar Tikadar, Mrityunjoy Kunda + Show 1 more

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https://doi.org/10.1016/j.heliyon.2021.e08478

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Abstract

Gorai River is one of the important rivers in Bangladesh for rich aquatic biodiversity. The river is originated from the Ganges-Padma River system, a trans-boundary river between India and Bangladesh. Once the river was rich in fish biodiversity, but due to man-made and natural causes the availability of fish reduced drastically. A comprehensive analysis of fish diversity indices, gear efficiency, catch composition and decline causes of fish diversity in Gorai River, Bangladesh was accomplished. The data were collected on monthly basis from January to December 2018 from three major fishing sites of the river. A total of 62 fish and 2 prawn species under 12 orders and 24 families were recorded. Cypriniformes was the leading order consisting 27% of the total catch. The mean values of Shannon-Weaver diversity (H′), Simpson's index (1-D), Margalef's richness (d) and Pielou's evenness (J′) indices were recorded as, 1.478 ± 0.495, 0.57 ± 0.197, 15.115 ± 4.435 and 0.481 ± 0.152, respectively. At the similarity of 58.7%, two groups were attained in the cluster analysis and the Non-metric Multidimensional Scaling (nMDS) showed 40% similarity among the three sites in twelve months based on the Bray-Curtis similarity matrix. The highest and lowest CPUE were recorded from seine net (5.2 ± 1.72 kg gear−1 haul−1) and hook & long lines (0.0135 ± 0.0015 kg gear−1haul−1), respectively whereas, highest and lowest gear efficiency were recorded from lift net (0.321 ± 0.036 kg gear−1person−1hour−1) and fish trap (0.0005 ± 0.0002 kg gear−1person−1hour−1), respectively. Alternatively, the highest fish catch was recorded on April (21228 ± 464.38 kg) and lowest on August (3855 ± 138.21 kg). According to the fishermen fish biodiversity of the Gorai River declined day by day due to overexploitation, destructive fishing practice, pollution, construction of obstacles for fish movement, and natural causes like siltation. Proper implementation of fish acts and regulations, use of authorized fishing gear, community-based fisheries management, sanctuary establishment and management, stocking of fish fingerling, and raising public awareness can play a great role in enhancing and conserving fish biodiversity in the Gorai River of Bangladesh.

Highlights

Bangladesh, with its large river systems, has significant capture fishery potential and the suitable geographic location of Bangladesh comes with a large number of fish and other aquatic species (Shamsuzzaman et al, 2017)
Once the river was rich in fish biodiversity and the livelihood of thousands of fishers' families were fully dependent on Gorai River, but in the recent years due to many man-made and natural causes the availability of fish was drastically reduced (Hanif et al, 2016)
The fishing gears were overviewed by direct physical perceptions and dependent on participatory rural appraisal (PRA), for example, questionnaire interview (QI), focus group discussion (FGD), and cross-checking of data by key informant interviews (KII)

Summary

Introduction

Bangladesh, with its large river systems, has significant capture fishery potential and the suitable geographic location of Bangladesh comes with a large number of fish and other aquatic species (Shamsuzzaman et al, 2017). The Gorai River ecosystems originated from the Ganges-Padma River system play a vital role in supporting the biodiversity of fish fauna and contribute to the supply of animal protein and overall economy of the south-western part of this country through fish production (Hanif et al, 2016; Rahman et al, 2012). In the last few decades, stress caused by anthropogenic degradation due to urbanization, construction of dams, abstraction of water for irrigation and power generation, and pollution had many negative impacts on the biodiversity of freshwater fish species in the river (Sarkar et al, 2008). The importance of monitoring biodiversity in the protected areas has been realized by the developing countries (Danielsen et al, 2000)

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