Native fish species have significantly decreased across almost the entire territory of Armenia, while in many places introduced, often invasive species dominate, which were not previously encountered here. This is evidenced by the findings of studies conducted by Samvel Pipoyan, Doctor of Biological Sciences, Professor, and Head of the Department of Biology, Chemistry, and Their Teaching Methodology at Khachatur Abovyan Armenian State Pedagogical University.
"Armenia's ichthyofauna is currently undergoing transformation. In the past, only 22 fish species were known in Armenia, but now this number has grown to over 50. In other words, about 60% of the fish species currently found in Armenia are alien species, introduced or invasive from other regions," said Samvel Pipoyan in his interview with EcoLur.
According to the expert, this situation has been primarily influenced by changes made to riverbeds. The ichthyologist lists several factors: the use of water resources for agricultural or hydroenergetic purposes, climate change, and illegal fishing.
As part of the monitoring program of Armenia's small hydropower plants (SHPPs), Professor Pipoyan, together with EcoLur's expert team, studied 47 rivers and 125 small HPPs across Armenia's regions. The monitoring revealed a number of issues, including insufficient environmental flow, functional inconsistencies in SHPP fish passages and fish protection nets.
"The riverbed often becomes completely dry, and an ecological flow of water is not maintained to ensure the stable state of the river ecosystem. The natural conditions for the life activities of aquatic organisms, particularly fish, are disrupted, which leads to a sharp decline in the diversity and resources of these animals," Samvel Pipoyan explained.
The Yeghegis basin is the "richest" in terms of SHPPs, with 17 SHPPs. "On the Yeghegis River alone, which is 47 km long, 12–13 small HPPs are operational. Water exits the pipe of one HPP and, within just 10–20 meters, flows into the intake structure of another, then into a pipe again. About 50% of the river is entirely diverted through pipes," said Samvel Pipoyan and added, "Currently, only 3–4 fish species remain in the lower reaches of the Yeghegis River, while many fish species in the upper reaches have already disappeared."
Samvel Pipoyan described the state of fish passages in SHPPs: "I have visited 125 SHPPs, and only 1–2 of their fish passages allow fish to migrate from the lower reaches to the upper reaches and continue their journey. In other cases, the fish passages are constructed in such a way that they do not support the migration of most fish. Regarding SHPPs, we are facing the risk of losing micro-ecosystems."
The ichthyologist noted the necessity of reconstructing SHPPs, particularly their fish passages, as well as revising the methodology for calculating environmental flow. For constructing fish passages, Samvel Pipoyan proposed a new labyrinth-like design. The river is divided into two parts: one part continues along its natural course, while the other flows into the intake structure. This approach could solve 60% of the problems of Armenia's SHPPs. For the remaining 40%, fish passages made of natural stones could be constructed.
Rivers and river biodiversity are becoming more vulnerable under the conditions of climate change.
"According to projections, this will lead to a reduction in water resources. We will face problems with the state of rivers and the efficiency of HPP operations. There will not be enough drinking water or irrigation water. The organisms living in rivers, particularly fish, will have even worse living conditions," Samvel Pipoyan noted.
The article was produced with the financial support of the Media Initiatives Center within the framework of "Expanding Production of Independent Content" grant project.
November 22, 2024 at 17:54