The Impact of Water Hyacinth on the Welfare of Fishing Communities: Evidence From Lake Tana Fisheries, Ethiopia

ABSTRACT Water hyacinth (hereafter, WH) is known as ‘the green devil' and becomes a threat to the fishing community whose livelihood solely relies on fishing activities. Although there are immense assessment studies related to WH, the real causal impact of this invasive weed on the fishing community has not yet been properly quantified. In filling this gap, the present study aimed to estimate the causal effect of WH on the net fishing income, technical efficiency level, income poverty and poverty gap around Lake Tana, Ethiopia. In addressing these, the study used about 593 randomly drawn fishers from both infested and non‐infested areas. Propensity score matching (PSM) and the ‘doubly robust' inverse probability‐weighted regression adjustment (IPWRA) methods were employed to estimate the average treatment effects of WH. In addition, heterogeneous treatment effect analysis was conducted to identify fishers who are most impacted by WH, given observable characteristics. The study provides adequate evidence that WH has a significant and negative impact on the welfare of fishers. However, the degree of causal effects on the outcomes of interest is not homogenous among fishers from infested areas. The results from the treatment heterogeneity reveal that the impact of WH is higher for artisanal and less experienced fishers than for their counterparts. These findings suggest that eradication (if possible) or control of WH in the study area could significantly contribute to the poverty reduction endeavours within the fishing community.