Tese de Doutorado
A Influência da capacidade natatória de peixes neotropicais no projeto hidráulico de mecanismos de transposição
Fecha
2007-03-30Autor
Hersilia de Andrade e Santos
Institución
Resumen
The legislation of some Brazilian states nowadays obliges the study of the necessity of fishway construction in waterway barriers. Therefore, many fish ladders and lifts have been constructed on main Brazilian rivers but there has never been a concern about our fish swimming capability. They are based on Europeans, Canadian and American built fishways, designed to pass salmons, eels and trout. However, the Brazilian fishes are very different from this fish and therefore, have different swimming capability. This characteristic is the most important to the hydraulic project of fishway and auxiliary structures, such as entrance, exits and attraction water. But unfortunately the neotropical swimming capability is unknown because of the lack of study about it. Therefore, my proposal is to determine the swimming speed of some neotropical species, whose genus are common in our migratory ictiofauna, and to propose the possible changes, based on our fish swimming, in the hydraulic project of fishway which can be constructed in Brazil. In order to obtain the fish velocity, some methodology are reproduced in two respirometers, built in the Centro de Pesquisas Hidráulicas. Two kinds of swimming speed are measured: critical speed and prolonged speed. The fish is forced to swim, inside a water tunnel, against current water that is generated by a pump. The proceeding of critical velocity is to raise the water flow until the fish fatigue. To determine the prolonged mode, the fish swim in permanent flow until its fatigue, when its swimming time is taken. The chosen species: Pimelodus maculatus, Leporinus reinhardti and Prochilodus costatus; come from the São Francisco basin. Its speeds are going to be the base to analyze the criteria of fishladder project, which will give the maximum flow speed. Therefore, I evaluated if the fishladder from UHE Igarapava is able to permit the studied fish passage, according to the criteria, and to propose. The numerical method was used to build the velocity profile inside this fish ladder.