&lt;b&gt; Temporal distribution of ichthyoplankton in the Forquilha river, upper Uruguay river – Brazil: Relationship with environmental factors &lt;/b&gt; - doi: 10.4025/actascibiolsci.v36i1.17993

Carolina Antonieta Lopes,Evoy Zaniboni-Filho,Valquíria Garcia,David Augusto Reynalte-Tataje,Alex Pires De Oliveira Nuñer

doi:10.4025/actascibiolsci.v36i1.17993

<b> Temporal distribution of ichthyoplankton in the Forquilha river, upper Uruguay river – Brazil: Relationship with environmental factors </b> - doi: 10.4025/actascibiolsci.v36i1.17993

Carolina Antonieta Lopes, Evoy Zaniboni-Filho + Show 3 more

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https://doi.org/10.4025/actascibiolsci.v36i1.17993

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Abstract

This study aimed to evaluate the temporal distribution of fish eggs and larvae in the Forquilha river (upper Uruguay river/Brazil) and its relationship with environmental variables. Ichthyoplankton and abiotic factors were sampled from September 2006 to August 2007. At the laboratory, samples were sorted and larvae were identified to the lowest possible taxonomic level. For data analysis we applied One-way Anova, Tukey’s test, Pearson correlation and PCA. In this study 200 eggs and 308 larvae were collected, showing differences in the temporal distribution and influence of abiotic factors. Larvae were identified in all stages of development, being distributed in three order and eight families. These results point that the lower portion of the Forquilha river is an important drift and nursery area for fish larvae of the upper Uruguay river. The breeding season for most species was greatly marked, between October and January, coinciding with the increase in temperature and decrease of the water flow. The response of reproductive intensity varies according to the environmental variables.

Highlights

For a good understanding of the reproductive behavior of fish and its relationship with the environment, it is essential to know about their spawning areas and periods, as well as about the influence of environmental mechanisms on this process (BIALETZKI et al, 2005; SANTIN et al, 2009)
Reproduction of freshwater fish, independent on the strategy used, is highly cyclical, where the periodicity patterns are related to environmental conditions to which animals are exposed (SANTIN et al, 2009; REYNALTE-TATAJE et al, 2012)
It is a tributary of the Uruguay river that flows into the reservoir of the Machadinho Hydroelectric Power Plant (Figure 1)

Summary

Introduction

For a good understanding of the reproductive behavior of fish and its relationship with the environment, it is essential to know about their spawning areas and periods, as well as about the influence of environmental mechanisms on this process (BIALETZKI et al, 2005; SANTIN et al, 2009). Abiotic factors have great effect on the early stages of fish life cycle (SANTIN et al, 2009) and can accelerate or delay fish reproductive process, and affect the hatching of eggs, larval development, species growth and survival (BAUMGARTNER et al, 2008). Reproduction of freshwater fish, independent on the strategy used, is highly cyclical, where the periodicity patterns are related to environmental conditions to which animals are exposed (SANTIN et al, 2009; REYNALTE-TATAJE et al, 2012)

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