Migratory fishes of Brazil: Life history and fish passage needs

Abstract

Many of the most important commercial and recreational species of the megadiverse Brazilian freshwater fishes migrate in rivers among essential habitats during all life stages. These movements, however, have been severely blocked by hundreds of hydroelectric dams and reservoirs and they will be even more obstructed due to hundreds of new developments. Fishways have been used in many countries to allow fish to pass around dams. Fishway construction is booming in Brazil, but poor understanding of migrations by Brazilian fishes has led legislators, scientists, and the public to several misconceptions about the rules of fishways in fisheries conservation. First, is a belief that fishways are only needed to facilitate upstream spawning migrations. Also, it has been suggested that upstream passage for Neotropical migrant fishes is not useful if there is no large free-flowing stretch upstream of a dam that contains spawning habitat and has a large natural floodplain (nursery habitat). In this paper, we discuss that, in addition to providing passage for pre-spawning migrants, upstream fishways also provide passage for other fish migrations (e.g. foraging), and that all up-and downstream migrations during life history need to be addressed at dams to conserve fish resources. We also argue that an upstream fishway is important even if the upstream reach does not have spawning or nursery habitats. In addition, we discuss the need for protection of downstream migrant fish, and the importance of fish behaviourists and engineers working together on fishway design and operation to solve fish passage issues.

Effects of Renewable Energy Production and Infrastructure on Wildlife

“…Dams can also constitute important or absolute barriers for species that move along river systems, using different habitats within the year and/or during different life-history stages. This is the case for several fi sh species in the Amazon basin, which have been severely affected by hydropower development in Brazil (Godinho and Kynard 2009 ), and also of different river dolphins in Asia (Dudgeon et al 2006 ).…”

Evaluation of techniques used to protect tailrace fishes during turbine maneuvers at Três Marias Dam, Brazil

“…The goal of these barriers is to prevent reservoir forebay fish from entering the turbines through the water intake (Odeh & Orvis, 1998). Passage through turbines by reservoir forebay fish in Brazilian dams has been poorly documented (Godinho & Kynard, 2009). While this phenomenon occurs, its extent remains unknown.…”

“…Species of the Prochilodus genus are detritivorous and play an important role in the energy flux of their habitats (Castro & Vari, 2003). Curimbas are migratory (Godinho & Kynard, 2009;Godinho et al, 2010;Alves, 2012) and are one of the major components of "arribação", a term used to describe the upstream migration of juvenile fish from nursery grounds (Godinho & Kynard, 2009). "Arribação" fish migrate up to TMD, and aggregate in the tailrace where they remain for days because there is no upstream passage (Godinho & Kynard, 2009).…”

Mapping the Critical Habitats for Migratory Species of the Upper Grande River Region, Minas Gerais State, Brazil

“…The distribution of critical habitats is also essential because some significant impacts related to fish passes, such as "source-sink" dynamics (Godinho and Kynard, 2009) and ecological traps (Pelicice and Agostinho, 2008), may take place depending on their distribution. Because the number of dams is rising in Brazil, there is an increased risk of migratory species being confined to short river stretches without spawning sites or floodplains.…”