Effects of reservoirs water level variations on fish recruitment

Abstract

The construction of hydroelectric power plants has many social and environmental impacts. Among them, the impacts on fish communities, which habitats are drastically modified by dams, with consequences across the ecosystem. This study aimed to assess the influence of water level (WL) variations in the reservoirs of the Itá and Machadinho hydroelectric plants on the recruitment of fish species from the upper Uruguay River in southern Brazil. The data analyzed resulted from the WL variation produced exclusively by the hydroelectric plants generation and were collected between the years 2001 and 2012. The results showed significant correlations between the abundance of juvenile fish and the hydrological parameters only for some reproductive guilds. The species that spawn in nests showed, in general, a clear preference for the stability in the WL of the reservoirs, while the species that spawn in macrophytes or that release demersal eggs showed no significant correlation between the abundance of juvenile fish and hydrological parameters. A divergence of results between the two reservoirs was observed between the species that release semi-dense eggs; a positive correlation with a more stable WL was only observed in the Machadinho reservoir. This result can be driven by a wider range of WL variation in Machadinho reservoir.Keywords: Hydrological Parameters, Itá, Juveniles, Machadinho, Reproduction, Uruguay River.A construção de usinas hidrelétricas implica em diversos impactos sociais e ambientais. Dentre esses, o impacto causado sobre a comunidade de peixes, cujos habitats são drasticamente modificados pelas barragens, causam consequências em todo o ecossistema. Este trabalho teve como objetivo avaliar a influência da variação dos níveis de água dos reservatórios das usinas hidrelétricas de Itá e Machadinho sobre o recrutamento das espécies de peixes do alto rio Uruguai, sul do Brasil. Os dados analisados resultaram da variação de nível de água decorrente exclusivamente da operação da usina e foram coletados entre os anos de 2001 e 2012. Os resultados mostraram correlações significativas entre a abundância dos juvenis de peixes e os parâmetros hidrológicos apenas para determinadas guildas reprodutivas. As espécies que desovam em ninhos mostraram, em geral, uma clara preferência pela estabilidade do nível de água dos reservatórios, enquanto que as espécies que desovam em macrófitas ou que liberam ovos demersais não mostraram correlação significativa entre a abundância de juvenis com os parâmetros hidrológicos. Uma divergência de resultados entre os dois reservatórios foi observada entre as espécies que liberam ovos semi-densos, onde apenas no reservatório de Machadinho houve correlação positiva com a maior estabilidade do nível de água. Esse resultado pode ser motivado pela maior amplitude de variação do nível de água no reservatório de Machadinho quando comparado com o de Itá.

Review on Governance in Hydroelectric Projects and Impacts on Natural Resources

“…Among these journals, Sustainability Switzerland with 3 publications; and Biological Conservation, Environmental Biology of Fishes, Plos One and Water Alternatives stood out with greater representation, with 2 publications each. The results of the literature analysis of the analyzed articles were grouped into 7 main themes and are illustrated in Figure 2: As shown in Figure 2, we highlight the studies concerned with the topic dealing with fish and the impact of hydroelectric enterprises in relation to them, object of study of the respective authors (Bhatt, Tiwari, & Pandit, 2017;Birnie-Gauvin, Larsen, Nielsen, & Aarestrup, 2017;Cebalho et al, 2017;Lima, Reynalte-Tataje, & Zaniboni-Filho, 2017;Pittock, Dumaresq, & Orr, 2017;Quinn, Bond, Brenkman, Paradis, & Peters, 2017;Yang, Tang, Tao, & Zhao, 2017).…”

Karakteristik Habitat Ikan Opudi (Telmatherina Prognatha Kottelat, 1991) Di Danau Matano, Propinsi Sulawesi Selatan

“…Keterkaitan reproduksi dengan parameter hidrologi memiliki korelasi yang signifikan terutama pada ikan-ikan yang menggunakan sarang dibandingkan dengan ikan yang melepaskan telurnya di area demersal (Lima et al, 2017). Ikan roach (Rutilus rutilus) yang hidup di water reservoir (Saidenbach Reservoir, Saxony, Germany) mengalami penurunan rekruitmen ketika terjadi penurunan tinggi muka air setelah terjadi pemijahan (Kahl et al, 2008).…”

A Forecasting and Prediction Methodology for Improving the Blue Economy Resilience to Climate Change in the Romanian Lower Danube Euroregion

“…Therefore, water level variations directly influence the abundance of periphyton, aquatic macrophytes and benthos and can indirectly affect phytoplankton and zooplankton [34], which are important nutritional sources for fish stocks. Moreover, according to previous studies [35], fish stocks can be affected if the water level changes rapidly during the reproduction period, a situation that applies particularly to substrate spawning fish species.…”