Biotic differentiation in headwater creeks after the massive introduction of non-native freshwater aquarium fish in the Paraíba do Sul River basin, Brazil

Abstract

This study evaluated fish beta diversity in six headwater creeks located in the area affected by the largest ornamental aquaculture center implemented in the Minas Gerais State, southeastern Brazil. We sampled fish assemblages in 2017 and 2018 to investigate changes in assemblage structure (species richness and beta diversity), comparing these data with the historic species pool. We recorded 60 fish species, of which 16 were native and 44 non-native with 19 translocated, and 25 exotic. The exotics Poecilia reticulata, Xiphophorus maculatus, X. variatus, Danio rerio, and Misgurnus anguillicaudatus were the most widely distributed in the headwater creeks. The Contamination Index showed that most creeks had high proportional contamination by exotic species (above 60%). Beta diversity increased from historical to contemporary periods in all creeks due to the introduction and differential colonization pressure of several non-native translocated and exotic species, indicating biotic differentiation. Temperature and number of ponds were the main preditors of change in beta diversity in the headwater creeks during the contemporary period. In summary, we observed that invaders have induced substantial changes to fish communities under influence of environmental filters. Our results support the hipothesis that aquaculture is a main driver of fish non-native fish introduction and native biodiversity loss in the Neotropics.

Non-native freshwater fish from drainages of Rio Grande do Sul State, Brazil

“…As already mentioned, the activities of aquaculture, fish farming and the intentional release to increase leisure fishing are recognized as the main causes of the introduction of exotic fish species in natural environments (Agostinho et al, 2007;Vitule et al, 2009;Latini et al, 2016;Casimiro et al, 2018), and consequently, loss of native biodiversity in the Neotropics (Magalhães et al, 2021). According to Gubiani et al (2018), the origins of non-native fish species in wild environments are linked to their introduction vectors, as several fish species arrive from areas close to where they are introduced, mainly by dams, sport fishing and aquaculture.…”

“…Most records for the states of Paraná and São Paulo are for tilapias O. niloticus and C. rendalli. Although there are few records available in collections for Minas Gerais (or these collections are not available in websites), however, in this state 44 non-native fish species (25 are exotic) are found only in the Rio Paraíba do Sul basin, and all of them come from the largest ornamental aquaculture center in the country (Magalhães et al, 2021). According to the study by Gubiani et al (2018), the Alto Rio Paraná ecoregion has the highest number of non-native fish species (105 species), followed by the Iguaçu ( 27 Pap.…”

Marine or freshwater: the role of ornamental fish keeper’s preferences in the conservation of aquatic organisms in Brazil

“…These species act by drastically modifying the ecosystems in which they settle, causing the decline of native species and resulting in biodiversity loss ( Mantelatto et al, 2018 ). All these alterations can influence beta diversity patterns ( i.e ., β-diversity), causing biotic homogenization ( Magalhães et al, 2021 ). There are introduction records of more than 150 non-native fish species in the last two centuries in Brazil, many of which were introduced through fish keeping ( Azevedo-Santos et al, 2015 ; França et al, 2017 ; Magalhães et al, 2017 ; Magalhães et al, 2021 ).…”

Here comes the large catfish “jaú” Zungaro jahu (Ihering 1898) (Teleostei, Pimelodidae): a new alarming case of fish introduction in a high-endemism Neotropical ecoregion

“…In fact, another large pimelodid herein recorded for the first time in the Iguaçu River basin above the Iguaçu Falls could cause serious new future damages to populations of native and endemic species in this basin. Previous studies have shown that richness, biomass, and beta-diversity between native and non-native fishes weakened over time with a gradual reduction on native, while nonnative evidenced an increase in these metrics in Neotropical environments (Ganassin et al, 2021b;Magalhães et al, 2021;Moi et al, 2021). Whilst the alert is imminent, the succession of dams (cascading reservoirs) along the Iguaçu River could difficult the dispersion of this nonnative species through the main river channel, from our record in the Segredo Reservoir until the arrival at the ecological sanctuaries of the "surubim-do-iguaçu".…”

“…Non-native fish species have been very closely related to serious damage regarding biodiversity loss (Vitule et al, 2009;Pelicice et al, 2014;Moi et al, 2021) due to their negative effects on native fauna such as competition, predation, habitat alteration, hybridization, parasitism, changes in the food webs, nutrient cycling, and in the last instance, ecosystem function [see Vitule et al (2009); Gois et al (2015); Rodrigues et al (2018); Ganassin et al (2021ª); Moi et al (2021)]. Although the negative impacts of the introduction of non-native fish species have a well-structured scientific basis, several new species continue to be introduced in aquatic environments of the Neotropical region (Gubiani et al, 2018;Doria et al, 2021;Magalhães et al, 2021), especially for economic reasons (e.g. aquaculture and sport fishing; Ribeiro et al, 2017;Garcia et al, 2018;Forneck et al, 2021), often sustained by public policies disqualified from scientific and technical criteria (Pelicice et al, 2014;Ota et al, 2019;Latini et al, 2021).…”