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Effectiveness of a fish ladder for two Neotropical migratory species in the Paraná River

Marine and Freshwater Research

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Abstract

We evaluated fish ladder effectiveness at Porto Primavera Dam in the Upper Paraná River, for two Neotropical migratory fish species. Overall, 564 fish (448 Megaleporinus obtusidens and 116 M. piavussu) were PIT-tagged, released in upstream and downstream areas (on the left and right banks), and monitored continuously for 4 years. The fish performed two-way movements through the fish ladder, ascending from the tailrace and descending from the forebay. We registered 46 M. obtusidens (10.3%) and only 3 M. piavussu(2.6%) from the fish ladder, therefore all analyses were focused on M. obstusidens. Entry proportion ranged from 0 to 48.1% depending on release site and was greatest for fish released downstream near the fish ladder entrance. Entry times ranged from 3.0 to 384.0 days, and median times were 32.9 and 25.8 days for downstream and upstream, respectively. Of fish that entered the fish ladder, passage percentages were 80% for fish release downstream and 100% for fish released upstream, and median transit time was 0.7 and 0.9 hours, respectively. Results suggest that if guidance and entry conditions can be improved, this fish ladder design holds promise as an effective solution for providing passage in both directions.

Additional publication details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Effectiveness of a fish ladder for two Neotropical migratory species in the Paraná River
Series title:
Marine and Freshwater Research
Edition:
Online First
Year Published:
2018
Language:
English
Publisher:
CSIRO
Contributing office(s):
Leetown Science Center