Larvae of migratory fish (Teleostei: Ostariophysi) in the lotic remnant of the Paraná River in Brazil

Evelyn Barzotto,Paulo Vanderlei Sanches,Lilian Orvati,Luiz Carlos Gomes,Andréa Bialetzki

doi:10.1590/s1984-46702015000400002

Abstract

Fish larvae and adults are morphologically distinct from each other and have different ecological requirements. Research on the dynamics of ichthyoplankton provides valuable information about the early stages of the life cycle of fish. This study analyzed the temporal and spatial distribution of the larval stages of three migratory species - Salminus brasiliensis (Cuvier, 1816), Prochilodus lineatus (Valenciennes, 1836) and Pseudoplatystoma corruscans (Agassiz, 1829) - to identify possible spawning areas in the last lotic remnant of the upper Paraná River, in the Brazilian territory. A total of 26 points were sampled monthly from October 2003 to November 2004. The PERMANOVA detected significant differences between the months only for S. brasiliensis (Pseudo-F = 3.88, p = 0.0021) and P. corruscans (Pseudo-F = 3.35, p = 0.004). Among the environmental variables, temperature was the most important and the Mantel test detected a significant correlation between temperature and the densities, only for P. lineatus (r = 0.09, p = 0.03). The species in our data chose for spawning tributaries that are not dammed, of which most are outside conservation areas. Therefore, recruitment, maintenance and possible actions aiming to recover the stocks of these species are dependent on the conservation of tributaries and floodplain lakes in the region, in addition to monitoring to prevent fishing during the reproductive period.

Highlights

Fish colonize all types of habitats, which are subjected to various environmental conditions
Despite the fact that three conservation units (Ilha Grande National Park, State Park of the Várzeas of the Ivinhema River, and Environmental Protection Area of the Islands and Várzeas of the Paraná River) are present in the area,the local fish fauna is especially impacted by the dams (AGOSTINHO et al 2000, SANCHES et al 2006), which directly impact water quality, spawning, and recruitment of populations (GOMES & AGOSTINHO 1997, PETRY et al 2003, AGOSTINHO et al 2004b)
This study aimed to evaluate the temporal and spatial distribution of larvae of three migratory species (S. brasiliensis, P. lineatus and P. corruscans) in the region of the upper Paraná River, located in the lotic remnant of the Paraná River in the Brazilian territory

Summary

Introduction

Fish colonize all types of habitats, which are subjected to various environmental conditions. Species of great commercial value in professional fishing, such as Salminus brasiliensis (Cuvier, 1816), Prochilodus lineatus (Valenciennes, 1836) and Pseudoplatystoma corruscans (Agassiz, 1829), are among the most vulnerable to habitat changes in the Paraná River basin (AGOSTINHO et al 1997). According to the Red List of Threatened Fauna of the state of Paraná (ABILHOA & DUBOC 2004), S. brasiliensis and P. corruscans are no longer abundant in the Paraná River basin These species are still found in this stretch of the river where there are several tributaries, many of which are outside the conservation units. These tributaries are still not dammed, and can be used by migratory species as alternative migration routes, for reproduction (SANCHES et al 2006)

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