6 research outputs found
Preliminary study on the application of radio-telemetry techniques to evaluate movements of fish in the Lateral canal at Itaipu Dam, Brazil
A barrier to upstream migration in the fish passage of Itaipu Dam (Canal da Piracema), Paraná River basin
A barrier to upstream migration in the fish passage of Itaipu Dam (Canal da Piracema), Paraná River basin
The majority of the fish passages built in the Neotropical region are characterised by low efficiency and high selectivity; in many cases, the benefits to fish populations are uncertain. Studies conducted in the Canal da Piracema at Itaipu dam on the Parana River indicate that the system component designated as the Discharge channel in the Bela Vista River (herein named Canal de deságue no rio Bela Vista or CABV), a 200 m long technical section, was the main barrier to the upstream migration. The aim of this study was to evaluate the degree of restriction imposed by the CABV on upstream movements of Prochilodus lineatus and Leporinus elongatus, Characiformes. Fish were tagged with passive integrated transponders (PIT tags) and released both downstream and upstream of this critical section. Individuals of both species released downstream of the CABV took much more time to reach the upper end of the system (43.6 days vs. 15.9 days), and passed in much lower proportions (18% vs. 60.8%) than those tagged upstream of this component. Although more work is needed to differentiate between fishway effects and natural variation in migratory motivation, the results clearly demonstrate passage problems at the CABV
Morphological description of larvae of the Mapar\ue1 Hypophthalmus edentatus (Spix) (Osteichthyes, Hypophthalmidae) in the Itaipu reservoir (Parana River, Brazil)
The ontogenetic aspects of larvae of Hypophthalmus edentatus (Spix, 1829) from the ichthyoplankton samples collected in the Itaipu reservoir between March 1988 and April 1990 were analysed. Sample were caught by 0.5 mm mesh conic-cylindrical plankton net. Larvae of H. edentatus were identified and described as Siluriforms from the morphological and morphometric development series. They have a small to medium-sized head, long body, small eyes, little pigmentation, mandibular barbules and 53 to 56 myomeres. High values obtained with correlation coefficient (r > 0.97; p < 0.001) show that growth was proportional in different parts of the body