Stakeholders' knowledge of threatened freshwater fishes and their involvement in fishery value chains in order to assist conservation in developing countries

Introduction: Improved conservation of exploited freshwater biodiversity is an increasing priority globally, but in developing countries there is often little insight of stakeholder attitudes within the value chains through which exploited species are passed, upon which to make informed management decisions. Methods: We determined knowledge concerning threatened freshwater fishes in Bangladesh by key stakeholder groups (fishermen, faria agents, commission agents, retailers and consumers; n = 485 respondents) and their participation level in the threatened fish value chain. We also determined factors affecting local ecological knowledge and participation in the value chain. Results and discussion: The highest mean number of threatened fish species (4.8 ± 3.5% of species) was identified by the fishermen group, whereas consumers identified fewest (0.5 ± 1.1% of species). All respondent groups participated in the threatened fish value chain and their participation varied across respondent groups. 45.3% of the total number of threatened fish species appeared in the value chain. Participation level was highest for commission agents, involved in the trade of 21.5 ± 4.2% of threatened fish species, and lowest for consumers (7.4 ± 6.5% of threatened species). For fishermen, the principal component “experience-income-age” and the interaction between education and financial loan factors affected fishers' participation in the threatened fish value chain positively whereas, this was negatively affected by their knowledge level of threatened fishes. This study reveals the poor knowledge of stakeholder groups regarding threatened fishes, but establishes their active participation in the value chain of these species in Bangladesh. With limited resources for conservation of threatened species in many developing countries, it is very risky to implement commonly used in-situ conservation methods (e.g., habitat quality improvement) without fuller buy-in from the stakeholders. Conclusions: We recommend specific protection laws for threatened fishes and awareness building campaigns for stakeholder groups to ensure minimum impact to threatened fish species. As overharvesting is a major cause of threatened fish species decline, such training programmes should be designed for fishers in developing regions. Education programmes on threats to ecosystems and biodiversity should be prioritized in schools and fishing communities. In addition, regular monitoring for protected species at harvesting sites and fishing markets should be ensured

Municipal wastewater can result in a dramatic decline in freshwater fishes: a lesson from a developing country

Impacts of ineffective wastewater management on the biodiversity of receiving waters in developing countries are poorly documented. Using a before-after-control-impact methodology, we measured the effects of untreated wastewater release on the fish community in the Barnoi River, Bangladesh. In 2006, prior to untreated wastewater discharge, fish abundance, species richness and water quality were similar across sampling sites. In 2016, after 8 years of wastewater release to the downstream reach, fish abundance and species richness were reduced by >47% and >35% respectively at downstream sites compared to unaffected upstream sites and >51% and >41% lower respectively compared to the pre-wastewater discharge period. The wastewater impact was particularly severe during months of low discharge (October–December). Water transparency, dissolved oxygen and pH were lower (P < 0.001) at impacted downstream sites compared to upstream sites. Nineteen species (41.3% of all species we recorded) are threatened in Bangladesh and the abundance of these species, except one, decreased significantly (P < 0.05) at the impacted sites. We recommend improved wastewater management by applying primary treatment facilities and incorporating reedbed filtration as a mean of biological treatment, into the canals carrying wastewaters. The success of such measures should be tested with fish species that were most responsive to wastewater, using the indicator species concept

Municipal wastewater can result in a dramatic decline in freshwater fishes: a lesson from a developing country

Impacts of ineffective wastewater management on the biodiversity of receiving waters in developing countries are poorly documented. Using a before-after-control-impact methodology, we measured the effects of untreated wastewater release on the fish community in the Barnoi River, Bangladesh. In 2006, prior to untreated wastewater discharge, fish abundance, species richness and water quality were similar across sampling sites. In 2016, after 8 years of wastewater release to the downstream reach, fish abundance and species richness were reduced by >47% and >35% respectively at downstream sites compared to unaffected upstream sites and >51% and >41% lower respectively compared to the pre-wastewater discharge period. The wastewater impact was particularly severe during months of low discharge (October–December). Water transparency, dissolved oxygen and pH were lower (P < 0.001) at impacted downstream sites compared to upstream sites. Nineteen species (41.3% of all species we recorded) are threatened in Bangladesh and the abundance of these species, except one, decreased significantly (P < 0.05) at the impacted sites. We recommend improved wastewater management by applying primary treatment facilities and incorporating reedbed filtration as a mean of biological treatment, into the canals carrying wastewaters. The success of such measures should be tested with fish species that were most responsive to wastewater, using the indicator species concept