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FIGURE 1 in Human impacts and the loss of Neotropical freshwater fish diversity

FIGURE 1 | Gender of authors in this Special Issue of Neotropical Ichthyology, considering all authors (n = 107) and the first author of each paper (n = 22).

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FIGURE 3 in Human impacts and the loss of Neotropical freshwater fish diversity

FIGURE 3 | Main human stressors associated with the loss of Neotropical freshwater fishes, investigated by studies published in this Special Issue of Neotropical Ichthyology.

FIGURE 5 in Assessing extinction risk from geographic distribution data in Neotropical freshwater fishes

FIGURE 5 | Collection points for 442 threatened Neotropical freshwater fishes (NFF) colored by elevation and sized by species' description year. Threatened NFF species are often those described decades ago, with range-restricted distributions in the upland rivers of the Brazilian Shield and the Colombian Andes, and coastal Atlantic and Caribbean drainages. CR: Critically Endangered; EN: Endangered; VU: Vulnerable; DD: Data Deficient (gray). Data for 4,412 localities with geographic coordinates.

FIGURE 6 in Assessing extinction risk from geographic distribution data in Neotropical freshwater fishes

FIGURE 6 | Collection points for 671 potentially threatened Neotropical Freshwater Fishes (NFF). Potentially threatened NFF species predicted by the ConR package using EOO estimates are usually distributed outside protected areas (e.g., national parks, indigenous lands: green) and more often located in the upland rivers of the northern, central and southern Andes, and Eastern Guiana Shield. CR: Critically Endangered; EN: Endangered; VU: Vulnerable; LC or NT: Least Concern or Near Threatened; DD: Data Deficient. Data for 4,412 localities with geographic coordinates. Protected areas (green) from: https://www.protectedplanet.net.

FIGURE 2 in Assessing extinction risk from geographic distribution data in Neotropical freshwater fishes

FIGURE 2 | Extinction risks in 3,001 Neotropical freshwater fishes (NFF). On average, 14% (422 of 3,001) NFF species are classified by the IUCN Red List (RL) as Vulnerable (VU), Endangered (EN) or Critically Endangered (CR). Extinction risks are relatively similar among the orders Characiformes (8.2%), Siluriformes (10.8%), Cichliformes (10.0%), and Gymnotiformes (14.9%). An exception is the clade Cyprinodontiformes, where about 48% of species are classified as either VU, EN, or CR. LC or NT: Least Concern or Near Threatened; DD: Data Deficient.

FIGURE 4 in Assessing extinction risk from geographic distribution data in Neotropical freshwater fishes

FIGURE 4 | Collection points for 442 threatened Neotropical freshwater fishes (NFF). Threatened NFF species classified by the IUCN Red List (RL) are often distributed in the upland rivers of the Brazilian Shield and the Colombian Andes, and coastal Atlantic and Caribbean drainages. CR: Critically Endangered; EN: Endangered; VU: Vulnerable; DD: Data Deficient. Data for 4,412 localities with geographic coordinates.

FIGURE 3 in Assessing extinction risk from geographic distribution data in Neotropical freshwater fishes

FIGURE 3 | Association among three variables and extinction risks in 3,001 Neotropical freshwater fishes (NFF). A. IUCN-Red List (RL) threat categories by species description dates. B. Species description dates by taxonomic orders. C. IUCN-RL categories by geographic ranges. D. Geographic ranges by taxonomic orders. E. IUCN-RL categories by elevation ranges. F. Elevational ranges by taxonomic orders. Threatened status are usually higher for recently described NFF species, those inhabiting narrow geographic ranges, and those confined to upland river drainages. CR: Critically Endangered; EN: Endangered; VU: Vulnerable; DD: Data Deficient.

FIGURE 1 in Assessing extinction risk from geographic distribution data in Neotropical freshwater fishes

FIGURE 1 | Sample of the phenotypic diversity of Neotropical freshwater fishes. Upper left to lower right: Lycengraulis grossidens (Spix & Agassiz, 1829); Hyphessobrycon hexastichos Bertaco & Carvalho, 2005; Geophagus neambi Lucinda, Lucena & Assis, 2010; Crenicichla lepidota Heckel, 1840; Trachelyopterus galeatus (Linnaeus, 1766); Anablepsoides xinguensis (Costa, 2010); Abramites hypselonotus (Günther 1868); Pituna xinguensis Costa & Nielsen, 2007; Gymnotus cuia Craig, Malabarba, Crampton & Albert, 2018; Apteronotus caudimaculosus de Santana, 2003; Colomesus tocantinensis Amaral, Brito, Silva & Carvalho, 2013; Corydoras britskii (Nijssen & Isbrücker, 1983). Species not shown in scale.

FIGURE 1 in Negative impacts of mining on Neotropical freshwater fishes

FIGURE 1 | Dead fishes (characiforms, cichliforms, and siluriforms) after crude oil spilled in waterbody of the Amazon River basin. Credits to Barbara Fraser.

FIGURE 7 in The cost of gold: Mercury contamination of fishes in a Neotropical river food web

FIGURE 7 | Relationships between body size (standard length, mm) and total Hg of fishes commonly used for consumption. Top panel (non-mined) contains three species that were common at mined sites (bottom panel). Relationships were estimated for five species that are commonly found and consumed, and for what a class structure was observed. Symbols represent individual fish. Clear diamonds = frugivores [1 sp.: Myloplus asterias (n = 19)], dark triangles = carnivores [1 sp.: Serrasalmus eigenmanni (n = 14)], green circles = piscivores [(3 spp.: S. rhombeus (n = 24), Ageneiosus ucayalensis (n = 2), Hoplias malabaricus (n = 1)].

FIGURE 6 in The cost of gold: Mercury contamination of fishes in a Neotropical river food web

FIGURE 6 | Mean Hg concentrations (dry weight) in sediments and instream biota separated by trophic groups (producers and consumers) between mined and non-mined sites in the Mazaruni River, Guyana. Species were grouped together based on their trophic guild. Polynomial trendline: y = 0.05x2 - 0.22x + 0.28, coefficient of determination R² = 0.98.

FIGURE 2 in The cost of gold: Mercury contamination of fishes in a Neotropical river food web

FIGURE 2 | Locations of sampling sites in the middle Mazaruni River drainage in A. Guyana within B. South America. Sampling sites included location in the C. Main channel of the Mazaruni River (mined) and three main tributaries including Eping River (non-mined), Puterang and Kurupung rivers (mined).

FIGURE 5 in The cost of gold: Mercury contamination of fishes in a Neotropical river food web

FIGURE 5 | Biomagnification of Hg in the Mazaruni River, Guyana, represented as the log total Hg concentrations plotted against nitrogen (δ15N) isotope ratios. Species were grouped together based on their trophic guild. Each symbol represents the average of all species within each trophic guild. The dashed horizontal line indicates the reference limit of 0.5 µg/g by WHO guideline for Hg in fish consumed by humans.

FIGURE 1 in The cost of gold: Mercury contamination of fishes in a Neotropical river food web

FIGURE 1 | Conceptual model of how Hg enters riverine food webs of the Mazaruni River, Guyana. First, artisanal gold mining operations installed in the river use a suction dredge to reach gold contained in bottom sediments. These mining operations use mercury for gold amalgamation of which the majority is lost to the atmosphere or river. Once in the river, Hg can be methylated by microbes into the toxic Methylmercury (MeHg) and be assimilated rapidly by aquatic biota. Hg concentration bioaccumulates and biomagnifies in the trophic food chain. Fishes at higher trophic levels [piscivores and carnivores (e.g., piranhas, aimaras, and catfishes)] are important items in the diet of local communities and can become a direct source of Hg uptake via direct consumption.

FIGURE 4 in The cost of gold: Mercury contamination of fishes in a Neotropical river food web

FIGURE 4 | Mean nitrogen (δ15N) and carbon (δ13C) isotope ratios of fish species collected from mined (right panel) and non-mined (left panel) sites in the Mazaruni River, Guyana. Species were grouped together based on their trophic guild. Each symbol represents the average of all species within each trophic guild. Numbers represent the basal resources collected at surveyed sites (1 = bryophyte, 2 = benthic algae, 3 = aquatic macrophytes). The abbreviations for the fish trophic guilds: Algivore/ Detritivore (Alg/Det), Insectivore (Insec), Herbivore (Herb), Omnivore (Omni), Carnivore (Carn), Piscivore (Pisc), as well as one shrimp (Macrobrachium).

FIGURE 3 in The cost of gold: Mercury contamination of fishes in a Neotropical river food web

FIGURE 3 | Sampling locations on the middle Mazaruni River: A. Main channel of the upper Eping River a small, black water tributary of the Mazaruni River. This river appeared more pristine and less impacted by gold mining activities; B. Sandy, shallow habitat sampled in middle channel of the upper Eping River; C. A gold dredge in the middle of the Kurupung River, on the right side is evidence of soil removal that resulted from mining activities; D. Deforestation (to establish mining stations) along the Kurupung River upstream, left bank from the confluence with the Mazaruni River; E-F. Main channel of the Mazaruni River at Olive Creek. At this location, the main channel of Mazaruni River is highly impacted by gold mining activities and gold dredges and 'tailing' beaches are commonly observed; G-H. The main channel of the lower Puterang River before the confluence with the Mazaruni River. At these locations, the Puterang River carries down heavily silted sediments that are spilled into the Mazaruni River.

FIGURE 5 in Structure and composition of ichthyofauna associated with cage fish farming and compared to a control area after severe drought in a Neotropical reservoir

FIGURE 5 | Redundancy analysis (RDA). Relation of ichthyofauna to the significant environmental variable (quota) in the drought and wet seasons in an area without the influence of fish farming (Control) at the Ilha Solteira reservoir, Upper Paraná River, São Paulo, Brazil. Ala = Acestrorhynchus lacustris, Acr = Astronotus crassipinnis, Cke = Cichla kelberi, Cpi = Cichla piquiti, Cbr = Cyphocharax gillii, Cgi = Crenicichla britskii, Gsv = Geophagus sveni, Hma = Hoplias aff. malabaricus, Mac = Megalancistrus parananus, Mli = Metynnis lippincottianus, Oni = Oreochromis niloticus, Ppl = Pimelodus platicirris, Ppi = Pinirampus pirinampu, Psq = Plagioscion squamosissimus, Pam = Pterygoplichthys ambrosettii, Rvu = Rhaphiodon vulpinus, Rde = Roeboides descalvadensis, Spa = Satanoperca pappaterra, Sin = Steindachnerina insculpta, Sit = Schizodon intermedius, Sna = Schizodon nasutus, Sma = Serrasalmus maculatus, Smg = Serrasalmus marginatus, Hbu = Heterotilapia buttikoferi, and Tne = Triportheus nematurus.

FIGURE 4 in Structure and composition of ichthyofauna associated with cage fish farming and compared to a control area after severe drought in a Neotropical reservoir

FIGURE 4 | Beta diversity (PERMDISP) in the drought and wet seasons in the control and fish farm areas at the Ilha Solteira reservoir, Upper Paraná River, São Paulo, Brazil. Average distances of centroids with presence/absence of data. Asterisks indicates significant upper value between seasons within each area.

FIGURE 3 in Structure and composition of ichthyofauna associated with cage fish farming and compared to a control area after severe drought in a Neotropical reservoir

FIGURE 3 | Box plots (minimum and maximum value = vertical line ends, standard error = box, and mean = horizontal line) of the ichthyofauna attributes in the control area and fish farm area, in the drought and wet seasons at the Ilha Solteira reservoir, Upper Paraná River, SP, Brazil. A. Total abundance; B. Species richness; C. Shannon index; D. Pielou evenness. Asterisks indicates significant upper value between seasons within each area. Hash indicates significant upper value between areas within each season.

FIGURE 2 in Structure and composition of ichthyofauna associated with cage fish farming and compared to a control area after severe drought in a Neotropical reservoir

FIGURE 2 | Historical series of the variation in quota (m) between 1999 and 2019 in the Ilha Solteira reservoir, Upper Paraná River, São Paulo, Brazil. The dots indicate the sampling period.