Swimming performance of the migratory Neotropical fish Leporinus reinhardti (Characiformes: Anostomidae)

Abstract

The fishways built in Latin America were mainly based on those used in the northern hemisphere for passing salmonids upstream. However, the swimming capacity in terms of speed and endurance is a major factor concerning the design of a fishway, and this information is not available for migratory neotropical fish species. Therefore, studies on swimming performance of neotropical species is fundamental. The aim of this study was to estimate the critical, sustained and prolonged speeds for the piau-três-pintas Leporinus reinhardti, and to evaluate the influence of water temperature on the swimming performance of the species. Variable (increasing) and fixed velocity tests were performed in a respirometer. When compared to other species whose critical speed data are available, the piau showed higher speeds, for a given total length. Fatigue times per prolonged speed class were estimated as well as prolonged speed per fatigue time class. The changing point from sustained to prolonged swimming was estimated to occur approximately at a speed of seven body-lengths per second (1.12 m/s for an individual with 16 cm total length: the first maturation length). In spite of the great swimming performance of piau, the adoption of efficient directives in fishway projects to allow the passage of neotropical ichthyofauna, will depend on a more detailed analysis of the swimming capacity of different species.As passagens para peixes construídas na América Latina são principalmente baseadas nos dispositivos existentes no hemisfério norte que, por sua vez, foram dimensionados para salmonídeos. Entretanto, a capacidade natatória das espécies migradoras, em termos de resistência e velocidade, é o principal fator a ser considerado no dimensionamento de uma passagem para peixes e estas informações ainda não são conhecidas para as espécies migradoras neotropicais. Dessa forma, o estudo da capacidade natatória das espécies neotropicais tornou-se uma necessidade. Este estudo tem como objetivo estimar as velocidades crítica, sustentável e prolongada do piau-três-pintas, Leporinus reinhardti, bem como avaliar a influência da temperatura da água na capacidade natatória. Testes de velocidade variável e fixa foram desenvolvidos em um aparato experimental do tipo respirômetro. Quando comparado a outras espécies, cujos dados de velocidade crítica são disponíveis, observa-se que o piau apresenta velocidades superiores para um mesmo comprimento total. Tempo de fadiga por classe de velocidade prolongada foram obtidos bem como a velocidade prolongada por classes de tempo de fadiga. O ponto de mudança do modo sustentável para o modo prolongado de natação foi estimado ocorrer em, aproximadamente, sete comprimentos por segundo (1.12 m/s para indivíduos com 16 cm de comprimento total: comprimento de primeira maturação). Apesar da grande capacidade natatória do piau, a adoção de critérios eficientes para o projeto de mecanismos de transposição para peixes neotropicais dependerá de análise detalhada da capacidade natatória de diferentes espécies.

The use of morphometric analysis to predict the swimming efficiency of two Neotropical long-distance migratory species in fish passage

“…Leporinus elongatus is faster than Prochilodus lineatus; it had a lower mean ascent time (1.39 hours) than P. lineatus (3.76 hours), which required a longer time to pass through the fish ladder. According to Santos et al (2007), the swimming capacity of the piau (Leporinus reinhardti) explained the success of this genus in ascending fishways in Brazil. It is possible that the swimming capacity of this genus is greater than that of other migratory characiformes.…”

“…However, studies of the swimming performance of these species have been conducted only recently, and this information is available for two migratory species: Leporinus reinhardti (Characidae) and Pimelodus maculatus (Pimelodidae) (Santos et al, 2007;2008). Furthermore, information on the functional relationships associated with morphology and with behavior in fish passages remains scarce.…”

Longitudinal habitat disruption in Neotropical streams: fish assemblages under the influence of culverts

“…According to Hoffman & Dunham (2007), the ability of fish to pass through culverts is affected by behavioral and physiological factors and by the physical conditions created by culverts. Studies carried out with Pimelodus maculatus (Siluriformes) showed that this species swims slower (Santos et al, 2006) than species of Characiformes, in the case of species considered as migratory, such as Leporinus reinhardti (Anostomidade) (Santos et al, 2007), and small-sized species, such as Bryconamericus stramineus (Characidae) (Castro et al, 2010). These characteristics can improve the Characiformes' ability to transpose obstacles, such as high water flows, which are frequently found in culverts.…”

Fish passage system in an irrigation dam (Pilcomayo River basin ): when engineering designs do not match ecohydraulic criteria

“…Beach, 1984;Zou, 1982;Videler, 1993;Keynard, 1993). Critical velocities have been estimated for non salmonid species inhabiting northern hemisphere (Pavlov, 1989) but swimming capabilities for neotropical species are still scant (de Castro et al, 2010;Santos et al, 2007Santos et al, , 2009. Most neotropical fishes are smaller than salmonids but compensate by displaying higher metabolic rates as they inhabit warmer rivers.…”