The Experts below are selected from a list of 1020 Experts worldwide ranked by ideXlab platform
Marcos Gomes Nogueira - One of the best experts on this subject based on the ideXlab platform.
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Dispersal of Fish eggs and larvae in a cascade of small hydropower plants with Fish Ladders
Hydrobiologia, 2020Co-Authors: Eduardo Meneguzzi Brambilla, Luiz G. M. Silva, Lee J. Baumgartner, Andréa Bialetzki, Marcos Gomes NogueiraAbstract:This study was conducted to investigate Fish eggs and larvae dispersal in a river stretch influenced by small hydropower plants in Southeast Brazil. The main hypothesis is that the downstream dispersal of free-flowing eggs and larvae is likely to occur given the small size of the studied reservoirs and that passage through the dam may occur, with the Fish ladder contributing to it. Eggs and larvae were collected fortnightly, between November 2016 and February 2017, from locations upstream of two dams, including lotic, transition and lentic zones. Additional samples were collected inside the Fish Ladders at each dam. Downstream dispersal of eggs and larvae was influenced by a combination of rainfall/flow variation and stage of the reproductive cycle, with the peak of rainfall during the summer coinciding with higher abundances. Under these conditions, eggs and larvae drifted downstream through the reservoirs and reached the dams. Once in the dam, they could pass through the Fish ladder. This passage was correlated with larval density in the reservoir immediately upstream, although at very low densities compared with the other sampling sites located upstream of the Fish Ladders.
Christopher A Peery - One of the best experts on this subject based on the ideXlab platform.
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indirect effects of impoundment on migrating Fish temperature gradients in Fish Ladders slow dam passage by adult chinook salmon and steelhead
PLOS ONE, 2013Co-Authors: Christopher C Caudill, Matthew L Keefer, Tami S Clabough, George P Naughton, Brian J Burke, Christopher A PeeryAbstract:Thermal layering in reservoirs upstream from hydroelectric dams can create temperature gradients in Fishways used by upstream migrating adults. In the Snake River, Washington, federally-protected adult salmonids (Oncorhynchus spp.) often encounter relatively cool water in dam tailraces and lower ladder sections and warmer water in the upstream portions of Ladders. Using radiotelemetry, we examined relationships between Fish passage behavior and the temperature difference between the top and bottom of Ladders (∆T) at four dams over four years. Some spring Chinook salmon (O. tshawytscha) experienced ∆T ≥ 0.5 °C. Many summer and fall Chinook salmon and summer steelhead (O. mykiss) experienced ∆T ≥ 1.0 °C, and some individuals encountered ΔT > 4.0°C. As ΔT increased, migrants were consistently more likely to move down Fish Ladders and exit into dam tailraces, resulting in upstream passage delays that ranged from hours to days. Fish body temperatures equilibrated to ladder temperatures and often exceeded 20°C, indicating potential negative physiological and fitness effects. Collectively, the results suggest that gradients in Fishway water temperatures present a migration obstacle to many anadromous migrants. Unfavorable temperature gradients may be common at reservoir-fed Fish passage facilities, especially those with seasonal thermal layering or stratification. Understanding and managing thermal heterogeneity at such sites may be important for ensuring efficient upstream passage and minimizing stress for migratory, temperature-sensitive species.
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Chinook salmon and steelhead body temperatures in relation to ambient Fish ladder water temperatures.
2013Co-Authors: Christopher C Caudill, Matthew L Keefer, Tami S Clabough, George P Naughton, Brian J Burke, Christopher A PeeryAbstract:Data were collected in 2000 and 2002 at the time Fish exited Fish Ladders (body temperature) and at the top-of-ladder monitoring site at Little Goose Dam (ambient temperatures). Linear regression results were: spring Chinook salmon (○), n = 128, F = 1378, P
Eduardo Meneguzzi Brambilla - One of the best experts on this subject based on the ideXlab platform.
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Dispersal of Fish eggs and larvae in a cascade of small hydropower plants with Fish Ladders
Hydrobiologia, 2020Co-Authors: Eduardo Meneguzzi Brambilla, Luiz G. M. Silva, Lee J. Baumgartner, Andréa Bialetzki, Marcos Gomes NogueiraAbstract:This study was conducted to investigate Fish eggs and larvae dispersal in a river stretch influenced by small hydropower plants in Southeast Brazil. The main hypothesis is that the downstream dispersal of free-flowing eggs and larvae is likely to occur given the small size of the studied reservoirs and that passage through the dam may occur, with the Fish ladder contributing to it. Eggs and larvae were collected fortnightly, between November 2016 and February 2017, from locations upstream of two dams, including lotic, transition and lentic zones. Additional samples were collected inside the Fish Ladders at each dam. Downstream dispersal of eggs and larvae was influenced by a combination of rainfall/flow variation and stage of the reproductive cycle, with the peak of rainfall during the summer coinciding with higher abundances. Under these conditions, eggs and larvae drifted downstream through the reservoirs and reached the dams. Once in the dam, they could pass through the Fish ladder. This passage was correlated with larval density in the reservoir immediately upstream, although at very low densities compared with the other sampling sites located upstream of the Fish Ladders.
Angelo Antonio Agostinho - One of the best experts on this subject based on the ideXlab platform.
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Fish Ladders: safe Fish passage or hotspot for predation?
Neotropical Ichthyology, 2012Co-Authors: Angelo Antonio Agostinho, Carlos Sergio Agostinho, Fernando Mayer Pelicice, Elineide Eugênio MarquesAbstract:Fish Ladders are a strategy for conserving biodiversity, as they can provide connectivity between fragmented habitats and reduce predation on shoals that accumulate immediately below dams. Although the impact of predation downstream of reservoirs has been investigated, especially in juvenile salmonids during their downstream movements, nothing is known about predation on Neotropical Fish in the attraction and containment areas commonly found in translocation facilities. This study analysed predation in a Fish passage system at the Lajeado Dam on the Tocantins River in Brazil. The abundance, distribution, and the permanence (time spent) of large predatory Fish along the ladder, the injuries imposed by piranhas during passage and the presence of other vertebrate predators were investigated. From December 2002 to October 2003, sampling was conducted in four regions (downstream, along the ladder, in the forebay, and upstream of the reservoir) using gillnets, cast nets and counts or visual observations. The captured Fish were tagged with thread and beads, and any mutilations were registered. Fish, birds and dolphins were the main predator groups observed, with a predominance of the first two groups. The entrance to the ladder, in the downstream region, was the area with the highest number of large predators and was the only region with relevant non-Fish vertebrates. The main predatory Fish species were Rhaphiodon vulpinus, Hydrolycus armatus, and Serrasalmus rhombeus. Tagged individuals were detected predating along the ladder for up to 90 days. Mutilations caused by Serrasalmus attacks were noted in 36% of species and 4% of individuals at the top of the ladder. Our results suggested that the high density of Fish in the restricted ladder environment, which is associated with injuries suffered along the ladder course and the presence of multiple predator groups with different predation strategies, transformed the Fish corridor into a hotspot for predation.
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selectivity of Fish Ladders a bottleneck in neotropical Fish movement
Neotropical Ichthyology, 2007Co-Authors: Carlos Sergio Agostinho, Angelo Antonio Agostinho, Fernando Mayer Pelicice, Deusimar Augusto De ,almeida, Elineide Eugênio MarquesAbstract:*Nucleo de Estudos Ambientais (Neamb), Universidade Federal do Tocantins, Campus de Porto Nacional, Rua 3, Quadra 17, Jardim do sIpes, 77500-000 Porto Nacional, TO, Brazil. agostinhocs@uft.edu.br**Nupelia, Universidade Estadual de Maringa, Av. Colombo, 5790, 87020-900 Maringa, PR, Brazil. agostinhoaa@nupelia.uem.br***Pos-Graduacao Ciencias do Ambiente, Universidade Federal do Tocantins. Av. NS 15, ALCNO 14, Bloco 3, Sala 15, 77010.970 Palm as,TO, Brazil.
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efficiency of Fish Ladders for neotropical ichthyofauna
River Research and Applications, 2002Co-Authors: Angelo Antonio Agostinho, Luiz Carlos Gomes, Domingo Rodriguez Fernandez, Harumi Irene SuzukiAbstract:The reproductive strategies of potamodromous Fish of the Plata basin involve upstream migration and passive downstream movements of eggs and larvae for dozens of kilometres. At the end of the downstream movements, the fry need marginal lagoons or bays in order for their development to be successful. The construction of reservoirs, often in series, has interrupted the movements, and is perhaps the main factor in the decrease in the abundance of migratory Fish in the basin. In an attempt to lessen the impact on the upstream migrations, Fish passages (floodgates, elevators and mainly Ladders) have been constructed and, despite limitations, they have functioned with relative success. Some studies show the continuity of the migration of individuals captured downstream and released into the reservoir. However, downstream migration of adult migratory species is made difficult by the fact that they are, in this phase, generally reophylic (live in running water) and occupy only the upper stretches of reservoirs (fluvial and transitional zones). It would be feasible only in short reservoirs and with a very short residence time. The fact that reservoirs present calm waters, more transparency and contain a large number of small Fish could delay the passive drift of eggs and larvae, exposing them to intense predation and/or promoting their settling toward deeper water, where the conditions of oxygenation are generally critical. In the remote event that the larvae reach the dam, most of them cannot be attracted to Ladders (elevators are conceived only for upstream movements) or driven away from the reservoir vicinities, in as much as they have passive movements and would therefore suffer great mortality if they passed through turbines or a spillway. In reservoirs with large free stretches upstream and endowed with ample natural floodplain areas, transposition can be an useful instrument in the maintenance of genetic heterogeneity since the number of transposed specimens does not compromise the stocks of the lower stretch. These limitations, connected to the strategy of neotropical Fishes, make Fish passages in most situations an inadequate instrument for preservational management. Copyright © 2002 John Wiley & Sons, Ltd.
Luiz G. M. Silva - One of the best experts on this subject based on the ideXlab platform.
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Dispersal of Fish eggs and larvae in a cascade of small hydropower plants with Fish Ladders
Hydrobiologia, 2020Co-Authors: Eduardo Meneguzzi Brambilla, Luiz G. M. Silva, Lee J. Baumgartner, Andréa Bialetzki, Marcos Gomes NogueiraAbstract:This study was conducted to investigate Fish eggs and larvae dispersal in a river stretch influenced by small hydropower plants in Southeast Brazil. The main hypothesis is that the downstream dispersal of free-flowing eggs and larvae is likely to occur given the small size of the studied reservoirs and that passage through the dam may occur, with the Fish ladder contributing to it. Eggs and larvae were collected fortnightly, between November 2016 and February 2017, from locations upstream of two dams, including lotic, transition and lentic zones. Additional samples were collected inside the Fish Ladders at each dam. Downstream dispersal of eggs and larvae was influenced by a combination of rainfall/flow variation and stage of the reproductive cycle, with the peak of rainfall during the summer coinciding with higher abundances. Under these conditions, eggs and larvae drifted downstream through the reservoirs and reached the dams. Once in the dam, they could pass through the Fish ladder. This passage was correlated with larval density in the reservoir immediately upstream, although at very low densities compared with the other sampling sites located upstream of the Fish Ladders.