Genetic Diversity of the Surubim-Do-Iguaçu, a Giant Catfish Species Threatened with Extinction: Recommendations for Species Conservation

Lenice Souza-Shibatta,Silvia H Sofia,Oscar A Shibatta,Maristela C Makrakis,Patricia S Da Silva,Suelen F R Pini,Dhiego G Ferreira,Sergio Makrakis,Lucileine De Assumpção

doi:10.3390/d14010016

Abstract

Steindachneridion melanodermatum is the largest catfish of the Lower Iguaçu River and is endangered due to the habitat fragmentation caused by dams. Currently, the wild population’s last refuge is restricted to an area of 190 km. This study presents the first analysis of its genetic diversity and population structure, using microsatellite loci and mtDNA. The population has an adequate level of genetic diversity, but signs of a recent bottleneck were observed. The Baixo Iguaçu Hydroelectric Power Plant has recently fragmented the population and threatened it with extinction in a reduced area of nearly 30 km. Based on our results, we strongly advise against the stocking of breeding specimens below the Salto Caxias HPP to not compromise the integrity of the native gene pools at the receptor sites. In addition, we recommend manual fish transposition, trap-and-haul, to maintain the genetic connectivity of individuals upstream and downstream of the dam as a conservation strategy. Furthermore, studies on behavior and swimming capacities, and suitable fishways for this species must be developed. We strongly recommend that the Lower Iguaçu River and its tributaries be protected and preserved as free from additional barriers to prevent future habitat disruption for the benefit of S. melanodermatum and several other endemic and endangered species.

Highlights

The world’s aquatic environments have faced intense deterioration due to habitat loss or degradation, water pollution, and over-exploitation [1,2]
The specimens of S. melanodermatum used in this study were the same in two recently published studies dealing with reproductive biology [29] and the species’ spatial distribution and abundance [19]
Of the 95 specimens of S. melanodermatum used in our study, 63 specimens were returned alive to the sampling site after removing a small part of the adipose fin

Summary

Introduction

The world’s aquatic environments have faced intense deterioration due to habitat loss or degradation, water pollution, and over-exploitation [1,2]. The Iguaçu River is one of the largest southern tributaries of the Paraná River, integrating the most heavily fragmented watershed in South America [8]. This river is the Diversity 2022, 14, 16. This river is the second most polluted urban river in Brazil [9], and the pollution is mainly from industrial and domestic sewage from urban areas in the Higher Iguaçu region [10]. Especially from contamination by pesticides used in agriculture, has negatively affected

Methods

Results

Conclusion