Fish rescue downstream of Porce III dam (Colombia) to reduce their mortality

Abstract

In the Magdalena River basin, fish rescue activities are an environmental management measure used to reduce fish mortality in the area near the reservoirs. When the opening and subsequent closing of the spillway gates is carried out as a result of the operation of the Porce III hydroelectric plant, downstream of the dam temporary aquatic habitats are created in the form of minor pools in the bedrock, where fish entrapment occurs. The objective of rescue activities is to relocate them to the main channel of the river, to reduce mortality. Between the years 2013 to 2020, a total of 4927 individuals were captured, representing 28 species, 12 families and five orders. We relocated 4704 individuals back to the Porce river, being the species of the genera Chaetostoma, Andinoacara, Astyanax and Rhamdia the highest capture. Potamodromous species of the family Prochilodontidae were also captured, their presence close to the dam possibly being due to the migrations they make to carry out their reproduction. These rescue and relocation actions resulting from the operation of hydroelectric plants should be replicated in the basin, as a strategy to mitigate the environmental impacts caused by habitat fragmentation.