From the headwaters to the Iguassu Falls: Inventory of the ichthyofauna in the Iguassu River basin shows increasing percentages of nonnative species

A new species of Cambeva (Siluriformes, Trichomycteridae) from the Rio Iguaçu basin, Paraná State, Brazil and redescription of Cambeva stawiarski (Miranda Ribeiro 1968)

This work aimed to describe Cambeva cauim, sp. nov., endemic to the Rio Iguaçu basin, Brazil and redescribe Cambeva stawiarski using external and internal morphological data through the revision of specimens deposited in fish collections, including the type material. In this process, we have also added comments on the possible type locality of C. stawiarski. C. cauim, sp. nov. and C. stawiarski are mainly diagnosed by the anatomy and number of procurrent caudal-fin rays in addition to colouration and several meristic and morphometric characters. Both species are compared with other possibly related species and their synapomorphic characters are discussed. C. cauim, sp. nov. and C. stawiarski along with eight other congeners are endemic to the Rio Iguaçu basin, a high impacted freshwater region which could be considered as a biodiversity hotspot to the genus.

Negative impacts of mining on Neotropical freshwater fishes

Abstract Mining activities have significantly affected the Neotropical freshwater ichthyofauna, the most diverse in the world. However, no study has systematized knowledge on the subject. In this review, we assembled information on the main impacts of mining of crude oil, gold, iron, copper, and bauxite on aquatic ecosystems, emphasizing Neotropical freshwater fishes. The information obtained shows that mining activities generate several different disturbances, mainly via input of crude oil, metals and other pollutants, erosion and siltation, deforestation, and road construction. Mining has resulted in direct and indirect losses of fish diversity in several Neotropical waterbodies. The negative impacts on the ichthyofauna may change the structure of communities, compromise entire food chains, and erode ecosystem services provided by freshwater fishes. Particularly noteworthy is that mining activities (legal and illegal) are widespread in the Neotropics, and often located within or near protected areas. Actions to prevent and mitigate impacts, such as inspection, monitoring, management, and restoration plans, have been cursory or absent. In addition, there is strong political pressure to expand mining; if – or when – this happens, it will increase the potential of the activity to further diminish the diversity of Neotropical freshwater fishes.

Fish fauna in low-order streams of the Piquiri River, Upper Paraná River basin, Brazil

Abstract The South America ichthyofauna encompasses the highest diversity of the world, however is highly threatened by anthropogenic actions. The fish fauna of nine low-order streams, tributaries of the Piquiri River and impacted by aquaculture, agriculture and urbanization were sampled in the present study. Samplings were done quarterly from December 2017 to September 2018 at three sites in each stream, using a portable electric fishing device in 50-meter segments. A total of 14,507 individuals were collected, belonging to six orders, 20 families, 46 genera, and 70 species. The highest richness and abundance were found for the orders Characiformes and Siluriformes. In this study, nine species that had not been recorded were found, totaling 163 for the basin. In addition, 14 non-native species were captured. The presented list of species contributes to the existing database of ichthyofauna distribution in Neotropical streams, denoting that it is underestimated in the region, mainly in low-order tributaries. The present study reinforces the importance of inventories and monitoring in environments with high biodiversity and sensitive to anthropogenic actions.