Potential effects of dam cascade on fish: lessons from the Yangtze River

Abstract

Construction of hydroelectric dams affect river ecosystems, fish diversity, and fisheries yields. However, there are no studies assessing the combined effects on fish caused by several adjacent dams and their reservoirs, as in a 'dam cascade'. This study predicts the potential effects that a cascade of ten dams currently under construction in the upper Yangtze River in China will have on local fishes, and uses such predictions to assess the effectiveness of possible fish conservation measures. We found that the dam cascade will have serious combined effects on fishes mainly due to impoundment, habitat fragmentation and blocking, flow regime modification, and hypolimnetic discharges. The impoundments will cause loss of critical habitats for 46 endemic species. The dams will fragment the populations of 134 species and will block migration routes for 35 potamodromous fishes.Corieus guichenoti will have a high risk of extinction due to the combined effects of impoundment and blocking. Modification of the flow regime will adversely affect the recruitment of 26 species that produce drifting eggs. The start of annual spawning for 13 fishes will be postponed by more than 1 month, and fish spawning and growth opportunities will be reduced due to low water temperatures associated with hypolimnetic discharges. Combined dam effects will further reduce the likelihood of successful recruitment of some endangered species, such as Acipenser dabryanus and Psephurus gladius. Three countermeasures hold promise to mitigate the nearterm effects of the dam cascade, including preservation and rehabilitation of critical habitat, restoration of a semi-natural flow regime, and stock enhancement that respects genetic integrity. These conclusions can guide the development of protection plans for fishes in the upper Yangtze River. The approach undertaken in this study-by which the known and likely effects of present and future dams were simultaneously Electronic supplementary material The online version of this article (doi:10.1007/s11160-015-9395-9) contains supplementary material, which is available to authorized users. 123Rev Fish Biol Fisheries (2015) 25:569-585 DOI 10.1007 considered in light of the biology of the specieshighlights the usefulness of ichthyology for fish conservation.

Temporal changes in fish diversity in lotic and lentic environments along a reservoir cascade

“…Generally in the long‐term, fish assemblages in reservoirs show dominance of small‐bodied species, with generalist feeding habits and sedentary lifestyles (Agostinho et al., ; Hoeinghaus et al., ). The evaluation of long‐term effects on fish diversity is better understood for single dams than for a series of dams in a cascade (Castello & Macedo, ; Cheng, Li, Castello, Murphy, & Xie, ). Reservoir cascades present longitudinal shifts in physical and biological parameters, which drives changes in biodiversity that can vary in intensity and direction depending on the longitudinal position of the impoundment (Miranda & Dembkowski, ; Miranda, Habrat, & Miyazono, ; Stanford & Ward, ; Ward & Stanford, ).…”

“…Reservoir cascades present longitudinal shifts in physical and biological parameters, which drives changes in biodiversity that can vary in intensity and direction depending on the longitudinal position of the impoundment (Miranda & Dembkowski, ; Miranda, Habrat, & Miyazono, ; Stanford & Ward, ; Ward & Stanford, ). Cumulative effects of multiple dams on fish assemblages are expected to be much stronger than those caused by a single dam alone (Castello & Macedo, ; Cheng et al., ). Therefore, a better understanding of the effects of reservoir cascades on fish assemblages is necessary, particularly in Brazil, where hydropower represents the country's main energy source.…”

Temporal fish community responses to two cascade run‐of‐river dams in the Madeira River, Amazon basin

“…Dams can be built isolated or in series—the latter known as cascade of dams, as found in Brazil (Agostinho et al, ; Petesse, Petrere, & Agostinho, ), China (Cheng, Li, Castello, Murphy, & Xie, ; Zhai, Cui, Hu, & Zhang, ) and United States (Bunn & Arthington, ). The river's longitudinal profile is one of the factors that determine the potential installation site of hydroelectric projects and the type of the turbine to be used, intending, almost exclusively, to maximize hydroelectric energy generation.…”

Characterization of the complete mitochondrial genome of Cynoglossus gracilis and a comparative analysis with other Cynoglossinae fishes

“…It is currently distributed across the northwestern Pacific from China to Korea (Menon, 1977). Its wild resources have been depleted and continue to be highly threatened due to massive water conservancy constructions, overfishing, and severe environmental contamination (Chen et al, 2002;Cheng et al, 2015).…”