Importance of protection strategies in the conservation of the flagship species “dourado” Salminus brasiliensis (Characiformes: Bryconidae)

Rosa Maria Dias1 , Oscar Peláez1, Taise Miranda Lopes1, Anielly Galego de Oliveira1, Mirtha Amanda Angulo-Valencia1 and Angelo Antonio Agostinho1

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In the upper Paraná River floodplain, the populations of Salminus brasiliensis have been subjected to several anthropic impacts, such as overfishing, the blocking of migratory routes by dams, and regulation of the flood regime. Its populations have disappeared or become depleted in most rivers in this basin. These populations are the target of protection measures aimed at restoring them. This study evaluated the abundance of this species in the upper Paraná River floodplain over a 26-year time series in sites under different degrees of protection. Despite the overall decrease in the abundance of S. brasiliensis across the region, the less impacted sites have higher abundances and exhibited a slower decline in the probability of occurrence. Over time, populations in less impacted sites also exhibited improved fish condition. Some protected areas in the upper Paraná River have had a mitigation effect by lowering the velocity of population decline and representing a constant source of propagule production for other areas. Our results reinforce the notion that populations threatened with low abundances take a long time to effectively recover their stocks. Thus, besides evaluating species conservation strategies, long-term studies are essential to subsidize management measures, such as fisheries regulations.

Keywords: Dams, Endangered native species, Migratory fish, River-floodplain system, Upper Paraná River floodplain.


Na planície de inundação do alto rio Paraná, as populações de Salminus brasiliensis têm sido submetidas a diversos impactos antrópicos, como sobrepesca, bloqueio de suas rotas migratórias por barragens e regulação do regime de cheias. Essas populações desapareceram ou se esgotaram na maioria dos rios dessa bacia, sendo alvo de medidas de proteção para restaurá-las. O objetivo deste trabalho foi avaliar a abundância da espécie na planície de inundação do alto rio Paraná ao longo da série temporal de 26 anos em locais sob diferentes graus de proteção. Apesar da diminuição geral na abundância de S. brasiliensis em toda a região, os locais menos impactados possuem maiores abundâncias e exibiram um declínio mais lento na probabilidade de ocorrência. Com o tempo, as populações em locais menos impactados apresentaram aumento na condição dos peixes. Algumas áreas de proteção no alto rio Paraná têm efeito mitigador, diminuindo a velocidade de declínio populacional, representando fonte de propágulos para as demais áreas. Nossos resultados reforçam a ideia de que populações ameaçadas com baixas abundâncias levam muito tempo para recuperar seus estoques. Assim, além de avaliar as estratégias de conservação das espécies, estudos de longo prazo são essenciais para subsidiar medidas de manejo, como a regulamentação da pesca.

Palavras-chave: Barragens, Espécies nativas ameaçadas de extinção, Peixes migradores, Planície de inundação do alto rio Paraná, Sistema rio-planície de inundação.


The loss of natural habitats due to the expansion and rapid growth of the human population (8–10 billion by 2050; United Nations, 2022) has increased habitat degradation and fragmentation (Zhao et al., 2019; Dias et al., 2021), which are among the main causes of biodiversity loss (Gorenflo, Brandon, 2006; Newbold et al., 2015). Freshwater ecosystems have been considered the most impacted worldwide due to human population growth, which has resulted in the increased use and regulation (e.g., flood control) of freshwater resources (Grill et al., 2015; Mekonnen, Hoekstra, 2016; Winemiller et al., 2016; He et al., 2019). Notably, dam construction causes changes in freshwater ecosystems that can have several pervasive impacts on fish community structure (Agostinho et al., 2016; Dias et al., 2020). In addition to blocking fish migration routes, dams also alter river flow regimes (Agostinho et al., 2004; Winemiller et al., 2016) and cause changes in abiotic conditions, such as increased water transparency due to sediment and nutrient retention (Roberto et al., 2009). Dams also facilitate the establishment of non-native species (Johnson et al., 2008) and limit species dispersal (Agostinho et al., 2004, 2007a; Affonso et al., 2015). The synergism of these impacts affects the maintenance of migratory species in freshwater ecosystems.

The large spatial scale involved in the reproductive processes of migratory fishes makes them sensitive to anthropogenic pressures. Additionally, the reproductive cycles of migratory fishes are synchronized with the variation of the hydrological regimes of rivers (Junk et al., 1989; Agostinho et al., 2004; Oliveira et al., 2020; Silva et al., 2020). Notably, fish require free river stretches to migrate to the uppermost regions of the basin, spawn, and allow their eggs and larvae to drift to flooded areas downstream for development (Nakatani et al., 2001; Wantzen, Junk, 2006). Thus, flood control by dams affects the reproduction and recruitment of migratory fishes (Ferguson et al., 2011; Oliveira et al., 2015, 2020). Moreover, since these species often reach large body sizes, they are the target of intensive fishing, which has caused depletion in many of their stocks (Agostinho et al., 2004). Additionally, some migratory piscivores are key species that regulate food chains through top down-control (Ruaro et al., 2019). Thus, maintaining a viable population of these species is pivotal for ensuring the balance and functioning of freshwater ecosystems (Meretsky et al., 2011).

Besides their impact on ecosystem functioning, the slow population growth rates resulting from their life histories (prolonged longevity, late maturation, and long generation time), as well as their restricted distribution ranges, make migratory fish species a priority for conservation (Pelicice et al., 2017; Wang et al., 2019). Among the fish species in the upper Paraná River floodplain that fit this description, we highlight the “dourado” Salminus brasiliensis (Cuvier, 1816), which has a vulnerable status on the threatened species list (Abilhoa, Duboc, 2004) and is of high fisheries importance. Since S. brasiliensis is considered a symbol of the regional fishery (Hoeinghaus et al., 2009), it has been used as a flagship in conservation strategies for not only conserving the species in question but also its ecosystem and the less-charismatic species within it via an umbrella strategy (Dietz et al., 1994; Oliveira et al., 2018; Ruaro et al., 2019).

Notably, S. brasiliensis presented taxonomic synonymy with Salminus maxillosus when the genus was reviewed by Lima et al. (2003). Salminus brasiliensis stands out for being the largest species among the Bryconidae (former Characidae) and plays an important ecological role because it is one of the largest predators within the environments in which it occurs (Zaniboni-Filho et al., 2017). The distribution of this species includes southern South America in the Paraná, Paraguay, and Uruguay rivers (de la Plata River basin), the Laguna dos Patos drainage, and the Chaparé and Mamoré rivers (Amazon basin) (Reis et al., 2003; Graça, Pavanelli, 2007). Although a large portion of the original S. brasiliensis distribution has been intensively regulated by dam cascades, the upper Paraná River still has an extensive floodplain and tributaries that are free of dams, which is important for maintaining populations of this and other migratory species (Agostinho et al., 2004; Affonso et al., 2015).

Among the measures aimed at protecting this and other endangered fish species, establishing protected areas (e.g., parks and other types of reserves; Roque et al., 2018) and controlling fishing exploitation stand out. Protected areas often export resources and individual organisms that can bolster populations outside reserve boundaries (Hunter, Gibbs, 2007). In the Paraná River basin, fishery control measures are based on laws prohibiting fishing for endangered native species (i.e., Law nº 19789/2018 – Government of the State of Paraná; Law nº 22/2018 – Government of the State of Mato Grosso do Sul), the capture and consumption of undersized fish (i.e., Federal law nº 9605/1998), and fishing during spawning periods (i.e., Federal law nº 7653/1988), as well as laws facilitating the passage of fish across dams (Agostinho et al., 2002) and catch and release fishing (i.e., Portaria IAP nº 211/2012 – Government of the State of Paraná).

Such conservation measures intend to increase population abundance. However, increasing fish abundance also depends on the fitness and reproductive success of the individuals as determined by their ability to avoid predators, foraging success, and response to environmental variability (Toïgo et al., 2006; Hilborn et al., 2017). Some of these features might manifest in the individual health condition (Schulte-Hostedde et al., 2005; Stevenson, Woods, 2006; Gubiani et al., 2020). Besides changes in abundance, determining whether populations are successful in obtaining resources for growth and allocating resources for reproduction is important information for assessing whether a population is maintaining itself in the environment. For threatened populations, such assessments are essential since the main objective of conservation biology is to ensure the long-term maintenance of species (Hunter, 2001; Primack, 2006).

In this context, the general objective of this paper was to evaluate variations in the abundance of an extinction-vulnerable species (S. brasiliensis) the last remaining stretch of the upper Paraná River floodplain over 26 years and consider areas with different levels of conservation/degradation. We expected that a decreasing trend in the abundance of S. brasiliensis in a highly altered river (HA – Paraná River) over this period has been directly affected by the construction of dams. In contrast, within rivers that have been less altered (LA – Ivinhema River), protected by parks (i.e., with more restricted uses, not regulated by dams), and even moderately altered (MA – Baía River; partially controlled by a dam and containing a less restrictive protected area), we expected an increase in S. brasiliensis abundance. We also expected a strong relationship between the abundance of species and the water level of the LA river. Moreover, we expected the probability of occurrence of this species and its young-of-the-year individuals to increase in the LA river. Additionally, we tested whether the abundance of S. brasiliensis in the more impacted sites (i.e., HA and MA rivers) depends on the abundance of the more preserved river (i.e., LA river) since it is expected that rivers with more restricted protection can represent a constant source of propagules for other rivers. Finally, we expected that adults with better body and reproductive conditions would be more frequent in the LA river.

Material and methods

Study area. The dam-free remnant of the upper Paraná River floodplain extends from the Porto Primavera Dam (closed in 1998) to the Itaipu reservoir (closed in 1982) 230 km downstream and includes tributaries, anastomosed channel networks, and floodplain lakes (Fig. 1). This stretch plays a fundamental role in maintaining fish populations and regional aquatic biological diversity (Agostinho et al., 2001; Luz-Agostinho et al., 2008). The Paraná River basin is considered the basin most heavily regulated by dams in South America (Souza Filho et al., 2004). Moreover, its flood pulse can be considered irregular when compared to other large tropical rivers (Thomaz et al., 2004). The construction of the Porto Primavera Dam modified water levels, reducing average levels downstream of the dam by 14% (Stevaux et al., 2009) and consequently reducing connectivity among biotopes during critical periods (Agostinho et al., 2009). However, the flood pulse remains primarily responsible for the seasonality and dynamics of the biotic communities of the floodplain and its associated habitats (Agostinho et al., 2004, 2009; Thomaz et al., 2007).

FIGURE 1 | Protected areas and sampling stations in the upper Paraná River floodplain. Paraná River (highly altered – HA), Baía River (moderately altered – MA), and Ivinhema River (less altered – LA).

At the end of the last century, this stretch was covered by conservation units with various degrees of use restrictions (Agostinho et al., 2004): Environmental Protection Area of the Islands and floodplains of the Paraná River (Área de Proteção Ambiental das Ilhas e Várzeas do Rio Paraná, 1,000,310 hectares of extension), which is included in the sustainable use category (Agostinho, Gomes, 2002); Ilha Grande National Park (Parque Nacional de Ilha Grande, 78,800 hectares) (Decree s/n., September 30, 1997); Ivinhema River State Park (Parque Estadual das Várzeas do Rio Ivinhema, 70,000 hectares) (Decree 9.278, December 17, 1998). Despite the creation of these environmental protection areas and conservation units, this region still has several anthropogenic impacts that cause habitat degradation and biodiversity loss (i.e., pollution, habitat destruction, deforestation, non-native species introduction, overfishing, and – most critically – the construction and operation of dams for hydroelectric purposes).

The upper Paraná River floodplain is characterized by three main rivers (Fig. 1): Paraná (highly altered – HA), Baía (moderately altered – MA), and Ivinhema (less altered – LA). Notably, the Paraná River exerts a predominant influence on the river dynamics of the entire floodplain (Rocha et al., 2001).

Sampling sites. Individuals of S. brasiliensis were collected during two periods over 26 years: before and after the construction of the Porto Primavera Dam. Before period: Fish were sampled monthly from October 1986 to September 1988 and March 1992 to February 1993, and then every two months from March 1994 to February 1995. The sampling was conducted at different sampling sites located in each river: Paraná (highly altered – HA): two sampling sites; Baía (moderately altered – MA): seven sampling sites; Ivinhema (less altered – LA): three sampling sites. For each river, a connected lake, an isolated lake, and the main river channel were sampled. After period: quarterly sampling was conducted for 19 years (from 2000 to 2018) at nine sampling sites located in each river (Paraná, Baía, and Ivinhema). For each river, a connected lake, an isolated lake, and the main river channel were sampled (Fig. 1). Fish were caught using a set of gillnets of different mesh sizes (3, 4, 5, 6, 7, 8, 10, 12, 14, and 16 cm between opposite knots), which remained exposed for 24 h and were checked at 8:00, 16:00, and 22:00 h. Captured fish were anesthetized with 5% benzocaine, sacrificed, identified according to Ota et al. (2018), measured [standard length (SL); cm], weighed [weight (W); g], and eviscerated. The gonads were analyzed to identify the sex and determine the stage of gonadal maturation (Vazzoler, 1996; Brown-Peterson et al., 2011). Individuals of S. brasiliensis with a total length < 28.3 cm were considered young-of-the-year (YOY; Oliveira et al., 2015). Some individuals of this species were deposited as vouchers in the ichthyological collection at Núcleo de Pesquisas em Limnologia, Ictiologia e Aquicultura (NUP), Universidade Estadual de Maringá, Maringá, Brazil (NUP 20110608025, NUP 2011061502, NUP 2010092002, NUP 2011081901, NUP 2010030301). Fish abundance was expressed in catch per unit effort (CPUE: individuals/1,000m2 gillnets during 24 h). This study was conducted as part of a long-term ecological research project (Site 6) supported by the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq).

Hydrologic data were provided by the National Water Agency (Agência Nacional das Águas – ANA; Sistema Nacional de Informações Sobre Recursos Hídricos – SNIRH) and obtained through daily water level measurements (WL; cm in relation to the operation of the Hydrometric Station at 231.8 m a.s.l.) conducted at a gauging station in the Paraná River (Estação Hidrométrica de Porto São José; register number: 64575000/ANA). The used time series was composed of the arithmetic mean of daily WL for the months when fish were collected.

Condition factor and gonadal index. To estimate the investment of individuals in growth, we considered their body weight-body length relationships. Variation in this relationship or condition factor (K) provides information on weight loss/gain, which can be related to the use of food resources and foraging success. The condition factor equation is presented as follows (Ricker, 1975): K = W/LSb, where W is the individual body weight, LS is the standard length, and b was determined to fit ordinary least square models (OLS) regressing the natural logarithm of body weight on the natural logarithm of body length. The condition factor was calculated for males and females separately while excluding the weight of the gonads and stomach. Juvenile individuals (< 21.4 cm for males and < 28.3 cm for females; Barbieri et al., 2001; Oliveira et al., 2015) were also excluded.

The gonadal index [GI; (GI = G/Wb)] (Vazzoler, 1996) evaluates the relationship between gonad weight (G) and body weight (W) and is frequently employed to compare reproductive condition across individuals or different groups of individuals of the same species. The GI was calculated separately for males and females within each river. The parameter b was determined to fit OLS regressing the logarithm of gonad weight on the logarithm of body weight through OLS models.

Data analysis. Negative binomial models were fitted for modeling total abundance (CPUE) and the probability of occurrence of the species (All) and young-of-the-year individuals (YOY). The probability of occurrence was computed as the number of samples in which species and YOY were detected each year. Then, we tested whether the abundance of S. brasiliensis differed before (1986 – 1995) and after (2000 – 2018) the Porto Primavera Dam closure and the creation of protected areas in the region. That is, we tested for differences in abundance among sampling periods (before-after) and the interaction with the river (predictor variables). We also determined whether the abundance was related to water level (cm). In these models, the response variables were the count of individuals per sample while controlling the sampling effort through a covariate.

A cross-correlation and a Granger causality test were conducted to test whether the abundance of S. brasiliensis in the most impacted sites (i.e., the Baía and Paraná rivers) depends on their abundance in the most preserved river (LA; Ivinhema River). In the cross-correlation, we searched for significant correlations between the temporal series of S. brasiliensis for each pair of sites. Cross-correlation allowed us to search for which extent of time two temporal series display concordant behavior. Although this method is often used to infer possible causal relations, it has been found to have a limited ability to determine the direction of causality. Thus, the Granger causality test seems more suitable for detecting causal relationships in ecological questions (Detto et al., 2012; Damos, 2016). Thus, we used the temporal series of the Ivinhema River as a predictor variable of the temporal series of the Baía and Paraná rivers in the cross-correlation. The cross-correlation protocol (Dean, Dunsmuir, 2016) was used to test the correlation among temporal series exhibiting autocorrelation. Overall, a procedure known as prewhitening first estimates a significance limit for the cross-correlations. Then, it fits an autoregressive model for the bivariate (each pair of rivers) time series to remove the autocorrelation from at least one of the temporal series and avoid significant spurious correlations. After identifying the lags of time at which significant cross-correlation between pairs of time series is detected, the Granger causality test was carried out. The Granger test was employed to investigate whether prior abundance in the LA river (Ivinhema River) predicted abundance at posterior samplings in the other two rivers. To make the results interpretable in terms of lags of time, only the period with quarterly sampling was considered (2004 – 2016).

Finally, an interaction effects ANCOVA model was fitted to test whether individuals in the most conserved river exhibited better body and reproductive conditions. The ANCOVA models were considered for females and males separately. These models allow for an evaluation of the homogeneity of slopes among rivers (e.g., whether individuals in some rivers gain more weight with increasing length than others). Differences in K values among rivers and periods were tested via two-way ANOVA. The same analysis was performed for the gonadal index (GI).

All analyses were performed in ‘R’ software (R Development Core Team, 2020) using the packages ‘MASS’ (Venables, Ripley, 2002) and ‘car’ (Fox, Weisberg, 2019) for model fitting as well as ‘DHARMa’ (Hartig, 2022) to analyze models’ residuals and fit.


Total abundance and the probability of occurrence of S. brasiliensis and young-of-the-year individuals. Over the 26 years of sampling, 872 S. brasiliensis individuals (492 females, 296 males, and 84 unidentified) were captured in the upper Paraná River floodplain. The surveyed rivers displayed a similar temporal trend in abundance variation: a decline from a high value between 1986 and 1995, an increase from low abundance between 2000 and 2009, and a posterior decrease (Fig. 2A). Before the construction of Porto Primavera Dam, the abundances were distributed more evenly over the three rivers. After the construction of dam, the Ivinhema River began to stand out by often exhibiting the highest abundances.

FIGURE 2 | Salminus brasiliensis in three rivers of the upper Paraná floodplain. A. Temporal trend in abundance – dashed line indicates the year in which the Porto Primavera Dam began to operate; B. Relationship between water level and abundance (CPUE). The less altered (LA) river has a weaker relationship between water level and young-of-the-year abundance. HA – highly altered (Paraná River), MA – moderately altered (Baía River), and less altered – LA (Ivinhema River); C. Probability of occurrence of the species (All) and young-of-the-year (YOY).

The less altered sites (LA; Ivinhema River) had a higher abundance, which was 75% higher than the moderately altered (MA; Baía River) and 50% higher than the highly altered (HA; Paraná River) sites. When tested for differences in abundance among periods (before and after the construction of the Porto Primavera Dam), only the interaction (River x Period) was significant. The abundance mainly differed among periods due to a decrease in the MA and HA rivers, whereas the LA river maintained a higher abundance over time (Fig. 2A). However, after the closure of the Porto Primavera Dam, the LA river accounted for 68% of the CPUE, reducing at a rate of -0.11 each year (R2 = 0.24; P < 0.001). No significant reduction trends were observed in MA (slope = -0.03; R2 = 0.04; P = 0.09) or HA (slope = -0.01; R2 = -0.01; P = 0.65). For all sites, the abundance of S. brasiliensis was positively related to water level. Nevertheless, contrary to our expectation, the relationship was stronger for the MA river (Fig. 2B).

The probability of occurrence of S. brasiliensis and the YOY showed a decline for all the rivers. These declines were larger in the MA river (All = -0.09; YOY = -0.08) and smaller in the LA river (All = -0.02; YOY = -0.002) (Fig. 2C).

Cross-correlation and Granger causality test. Cross-correlation showed that the temporal series of the MA and HA rivers had higher correlations with the LA river at negative lags of time (Fig. 3). Then, abundances in the MA and HA rivers could be in response to past changes in abundance within the LA river. The lag 1 (12 months) had a higher correlation for both rivers. However, the Granger causality test found that only the abundance in the HA river in response to the abundance in the LA river was significant (Tab. 1).

TABLE 1 | Granger test of causality. The upper row shows if the abundance in the HA – highly altered (Paraná River) and MA – moderately altered (Baía River) rivers have a causal relation with the abundance in the LA – less altered (Ivinhema River). The lower diagonal shows the inverse direction in causality. Bold letters indicate significant causality.



Response temporal series




Explanatory temporal series


F = 3.66; P < 0.01

F = 1.59; P = 0.20


F = 0.07; P = 0.80

F = 0.10; P = 0.74


F = 3.53; P = 0.07

F = 0.10; P = 0.76


FIGURE 3 | Cross-correlations between the temporal abundance series of the less altered (LA) and moderately altered (MA) rivers (LA:MA) and the LA and HA rivers (LA:HA). As sampling was conducted quarterly. A 0.25 lag is equal to three months. HA: Paraná River; MA: Baía River; LA: Ivinhema River). CCF = cross-correlation coefficient. After the prewhitening protocol correlations, < -0.27 and > 0.27 were considered significant (dashed line).

Condition factor and gonadal index. To investigate variation in K, 344 females and 137 males were considered. For females, the slope of the body weight x body length relationship was steepest in the MA river (b = 3.32), indicating that females in this river gained weight faster with increasing length (Fig. 4A). However, as shown by the ANOVA test, larger females (in length and weight) and individuals with higher Kvalues were found in the LA river (Fig. 4B). For males, the slope of the body weight x body length relationship was also steeper in the MA river (b = 3.40) (Fig. 4D). Higher K values were observed in the HA river and lower in the MA river (Fig. 4E). However, the K values increased over time in the LA river but remained stable in the HA river for both sexes (Figs. 4C, F).

FIGURE 4 | ANCOVA interaction effects for the relationship between body weight (bw) and body length (Ls) for female (A) and male (D) Salminus brasiliensis. Mean condition factor (K) for female (B) and male (E) S. brasiliensis by river (HA – highly altered; MA – moderately altered; LA – less altered). Condition factor (K) for female (C) and male (F) S. brasiliensis over time. K was measured as the relationship between ln(bw)/ln(Ls^3.13) for females and ln(bw)/ln(Ls^3.10) for males.

For both sexes, GI values showed similar patterns to those observed for K (Fig. 5). For females, GI was higher in the LA river (Fig. 5B). Moreover, an increase in GI over time was observed in the LA river for both sexes (Figs. 5C, F). The MA river had the lowest GI values and the smallest increase over time (Figs. 5B, C, E, F).

FIGURE 5 | ANCOVA interaction effects for the relationship between gonad weight (gw) and body weight (bw) for female (A) and male (D) Salminus brasiliensis. Mean gonadal index (GI) for female (B) and male (E) S. brasiliensis by river (HA – highly altered; MA – moderately altered; LA – less altered). GI for female (C) and male (F) S. brasiliensis over time. GI was measured as the relationship between ln(gw)/ln(bw^1.25) for females and ln(gw)/ln(bw^1.07) for males.


Despite an overall decrease in the abundance and occurrence of S. brasiliensis across the studied region, we found that the less impacted sites hold higher abundances and exhibited a slower decline in the probability of occurrence. Over time, populations in less impacted sites also exhibited increased fish condition (K and GI). Our results imply that the protection of some areas in the upper Paraná River has had a sound effect by reducing the velocity of S. brasiliensis decline.

The stocks of migratory species have diminished in many rivers due to overfishing and habitat modifications caused by dams (Agostinho et al., 2004). Salminus brasiliensis, an emblematicexample of this, is the most valuable species in artisanal and sport fishing in the upper Paraná River (Agostinho et al., 2005). Notably, even before the construction of the Porto Primavera Dam, a decrease in the abundance of this species was related to overfishing (Petrere Jr., 1996; Petrere et al., 2002; Agostinho et al., 2007b) since there was an absence of protected areas or laws that prohibited S. brasiliensis fishing during that period. Additionally, before the construction of the Porto Primavera Dam, the Paraná River was one of the most dammed rivers in South America and its floodplain had already been impacted by other forms of flow control made by the reservoir cascade (Agostinho et al., 2007a, 2016).

The creation of the “Parque Estadual das Várzeas do Rio Ivinhema” was a compensatory action due to the impacts of the Porto Primavera Dam. Moreover, this was accompanied by a ban on fishing of S. brasiliensis. In conjunction with the law regulating punishments for environmental crimes (Law nº 9605/1998), these actions likely caused the observed increase in the abundance of S. brasiliensis observed between 2005 and 2013. Moreover, successive years of drought (e.g., 2000 – 2001) increased the effects of the El Niño-Southern Oscillation (ENSO) in the La Niña phase (Grimm et al., 2000), concentrating fishes due to lower hydrologic levels in the sample sites. This favored the feeding of piscivorous and consequently increased their body condition factor, which could have increased the abundance of piscivorous fishes in the floodplain (Pereira et al., 2017). While such an increased fish density provides abundant and available food for piscivores over the short term (Luz-Agostinho et al., 2008; Pereira et al., 2017), food resources may become limiting for piscivorous species over more extended periods (Medeiros, Arthington, 2014).

The Porto Primavera Reservoir could be the primary driver of negative trends in the most impacted rivers (i.e., the MA and HA rivers). It directly regulates the seasonal fluctuation of floods for the Paraná River (HA river) and indirectly regulates the same for the Baía River (MA river) (Agostinho et al., 2007b). The absence of lasting floods has led to a recruitment failure and a reduction in the total abundance of S. brasiliensis in regulated rivers (Oliveira et al., 2015, 2020). Nonetheless, the probability of occurrence decreased across the three rivers, implying that regional pressures can also affect the populations in the LA river. For instance, the main migratory route of S. brasiliensis includes the main channel of the Paraná River, which is highly modified by upstream dams and thus retains sediments and nutrients (Roberto et al., 2009). Also, this channel is occupied by visually orientated alien piscivores (Peacock bass) that have better performance in capturing prey in clear waters (Ortega et al., 2020). Moreover, clear water reduces the chance of larvae from undammed tributaries surviving predation when arriving in the channel (Agostinho et al., 2016).

Previous studies have shown high densities of migratory species larvae in the Ivinhema River (LA river) (Baumgartner et al., 2004; Reynalte-Tataje et al., 2011; Barzotto et al., 2015; Rosa et al., 2019). Thus, the LA river constitutes an important available route for migratory species in this last lotic stretch of the Paraná River within Brazilian territory (Reynalte-Tataje et al., 2011; Affonso et al., 2015). Thus, S. brasiliensis reproduction in this stretch contributes to maintaining fish stocks — even in the HA river — considering a lag of 12 months. This appears to be congruent with the sink-source model (Pulliam, 1988; Marques et al., 2018), whereby the LA tributary is a propagule source whereas the HA tributary is a propagule sink. These results reinforce the importance of preserving free rivers without flood control to maintain the reproduction and recruitment of migratory species (Agostinho et al., 2001; Sanches et al., 2006; Reynalte-Tataje et al., 2011) and the important role of protected areas as propagule sources for surrounding areas (Hunter, Gibbs, 2007).

Migratory fish are high-quality habitat indicators (McDowall, Taylor, 2000) because they require specific environmental resources (e.g., spawning, nursery, and feeding areas) and large stretches of unimpeded river to complete their reproductive life cycles. One way to evaluate environmental quality is to measure some parameters of the target population, such as condition indexes (e.g., K and GI; Le Cren, 1951; Chang, Navas, 1984; Gubiani et al., 2020). The K of S. brasiliensis assemblages in the LA and MA rivers increased over time, with the LA river having the highest K values. This result supports our prediction that the river with the most effective protection will present better environmental quality and thus individuals in better nutritional condition. On the other hand, the assemblages of the HA river had a similar body condition between periods and maintained a constant nutritional condition after the hydroelectric dam closure. These results were likely due to the impacts caused by seasonal flood control.

Moreover, female S. brasiliensis of the MA river gained more weight with every centimeter grown. However, the population of the LA river had adults with the largest body lengths and heaviest gonads. As a strategy for maintaining their offspring, females from the MA and HA rivers must allocate more energy to developing their gonads at the expense of body growth and reproducing at shorter lengths (Audzijonyte, Richards, 2018). Under more favorable environmental conditions, the assemblage of the LA river can allocate its energy to body growth over time, thus favoring a larger body size than other populations. The presence of larger S. brasiliensis individuals in the LA river corroborates the results of Lopes et al. (2020) and demonstrates the effectiveness of protected areas and fishing prohibition laws (Laws nº 7653/1988 and nº 9605/1998) since larger fish are the target of commercial and recreational fishing.

Considering the conservation strategies for this freshwater fish species in the upper Paraná River floodplain over the past 26 years, the abundance of S. brasiliensis has generally declined, with a lower level of population decline observed in the most preserved river. Therefore, the implemented conservation strategies must be reinforced and monitored to avoid population decrease and local extinction. Furthermore, the conservation of the LA river also likely favors other migratory fish species. In this sense, the S. brasiliensis fishing prohibition law that came into force at the end of 2018 in Mato Grosso (Law nº19789/2018) and Paraná (Law nº22/2018) for 5 and 8 years, respectively, should only be suspended after studies can prove an increase in the abundance of this species in the region.

Most importantly, an ideal scenario involves the combination of protected areas and regulating the fishery and flood management in the upstream reaches to provide suitable conditions for reproduction. Moreover, all involved stakeholders should cooperate in developing conservation strategies. Our results reinforce the notion that fish populations with low abundances recover very slowly. Thus, long-term studies on this topic are essential to applying appropriate management measures, proposing relevant laws, and verifying the effectiveness of species conservation strategies.


The authors acknowledge all NUPÉLIA staff for the several years of work collecting these data. The collections were supported by the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) in the Long-Term Ecological Research (Programa de Pesquisas Ecológicas de longa duração – PELD – Sítio 6 A planície de inundação do alto Rio Paraná). CNPq was also responsible to support TML and AGO post-doctoral scholarships and AAA productivity grant. RMD is grateful for the post-doctoral scholarship awarded by PNPD (Programa Nacional de Pós-Doutorado) at the Universidade Estadual de Maringá (UEM) by Coordenação de Aperfeiçoamento Pessoal de Nível Superior (CAPES-PROEX).


Abilhoa V, Duboc LF. In: Mikich SB, Bérnils RS, editors. Livro vermelho da fauna ameaçada no estado do Paraná. Curitiba: Governo do Estado do Paraná/SEMA/IAP; 2004. p.581–682.

Affonso IP, Azevedo RF, Santos NLC, Dias RM, Agostinho AA, Gomes LC. Pulling the plug: Strategies to preclude expansion of dams in Brazilian rivers with high-priority for conservation. Nat Conserv. 2015; 13(2):199–203.

Agostinho AA, Bonecker CC, Gomes LC. Effects of water quantity on connectivity: the case of the upper Paraná River floodplain. Ecohydrol Hydrobiol. 2009; 9(1):99–113.

Agostinho AA, Gomes LC. In: Would Fisheries Trust, editor. Biodiversity and fisheries management in the Paraná River basin: Successes and failures. The blue millenium project: Managing fisheries for biodiversity. UNEP; 2002. p.1–30.

Agostinho AA, Gomes LC, Fernandez DR, Suzuki HI. Efficiency of fish ladders for Neotropical ichthyofauna. River Res Appl. 2002; 18(3):299–306.

Agostinho AA, Gomes LC, Pelicice FM. Ecologia e manejo de recursos pesqueiros em reservatórios do Brasil. Maringá: EDUEM; 2007a.

Agostinho AA, Pelicice FM, Petry AC, Gomes LC, Júlio Jr. HF. Fish diversity in the upper Paraná River basin: Habitats, fisheries, management, and conservation. Aquat Ecosyst Health Manag. 2007b; 10(2):174–86.

Agostinho AA, Gomes LC, Santos NCL, Ortega JCG, Pelicice FM. Fish assemblages in Neotropical reservoirs: Colonization patterns, impacts, and management. Fish Res. 2016; 173:26–36.

Agostinho AA, Gomes LC, Veríssimo S, Okada EK. Flood regime, dam regulation, and fish in the upper Paraná River: Effects on assemblage attributes, reproduction, and recruitment. Rev Fish Biol Fish. 2004; 14:11–19.

Agostinho AA, Gomes LC, Zalewski M. The importance of floodplains for the dynamics of fish communities of the upper river Paraná. Ecohydrol Hydrobiol.2001; 1:209–17.

Agostinho AA, Thomaz SM, Gomes LC. Conservation of the biodiversity of Brazil’s inland waters. Conserv Biol. 2005; 19(3):646–52.

Audzijonyte A, Richards SA. The energetic cost of reproduction and its effect on optimal life-history strategies. Am Nat. 2018; 192(4):150–62.

Barbieri G, Salles FA, Cestarolli MA. Growth and first sexual maturation size of Salminus maxillosus Valenciennes, 1849 (Characiformes, Characidae), in Mogi Guaçu River, state of São Paulo, Brazil. Acta Sci. 2001; 23(2):453–59.

Barzotto E, Sanches PV, Bialetzki A, Orvati L, Gomes LC. Larvae of migratory fish in the lotic remnant of the Paraná River in Brazil. Zoologia. 2015; 32(4):270–80.

Baumgartner G, Nakatani K, Gomes LC, Bialetzki A, Sanches PV. Identification of spawning sites and natural nurseries of fishes in the upper Paraná River, Brazil. Environ Biol Fishes. 2004; 71:115–25.

Brown-Peterson NJ, Wyanski DM, Saborido-Rey F, Macewicz BJ, Lowerre-Barbieri SK. A standardized terminology for describing reproductive development in fishes. Mar Coast Fish. 2011; 3(1):52–70.

Chang BD, Navas W. Seasonal variations in growth, condition, and gonads of Dormitator latifrons (Richardson) in the Chone River Basin, Ecuador. J Fish Biol. 1984; 24(6):637–48.

Damos P. Using multivariate cross correlations, Granger causality, and graphical models to quantify spatiotemporal synchronization and causality between pest populations. BMC Ecol. 2016; 16(33):1–17.

Dean RT, Dunsmuir WTM. Dangers and uses of cross-correlation in analyzing time series in perception, performance, movement, and neuroscience: The importance of constructing transfer function, autoregressive models. Behav Res Methods. 2016; 48:783–802.

Detto M, Molini A, Katul G, Stoy P, Palmroth S, Baldocchi D. Causality and persistence in ecological systems: A nonparametric spectral Granger causality approach. Am Nat. 2012; 179(4):524–35.

Dias RM, Oliveira AG, Baumgartner MT, Angulo-Valencia MA, Agostinho AA. Functional erosion and trait loss in fish assemblages from Neotropical reservoirs: The man beyond the environment. Fish Fish. 2021; 22(2):377–90.

Dias RM, Ortega JCG, Strictar L, Santos NCL, Gomes LC, Luz-Agostinho KDG, Agostinho CS, Agostinho AA. Fish trophic guild responses to damming: Variations in abundance and biomass. River Res Appl. 2020; 36(3):430–40.

Dietz JM, Dietz LA, Nagagata EY. In: Olney PJS, Mace GM, Feistner ATC, editors. The effective use of flagship species for conservation of biodiversity: the example of lion tamarins in Brazil. Dordrecht: Springer; 1994. p.32–49. Available from:

Ferguson JW, Healey M, Dugan P, Barlow C. Potential effects of dams on migratory fish in the Mekong River: Lessons from salmon in the fraser and Columbia Rivers. Environ Manage. 2011; 47:141–59.

Fox J, Weisberg S. An R companion to applied regression. Third edition.Sage Publishing. 2019. Available from:

Gorenflo LJ, Brandon K. Key human dimensions of gaps in global biodiversity conservation. Bioscience. 2006; 56(9):723–31.[723:KHDOGI]2.0.CO;2

Graça WJ, Pavanelli CS. Peixes da planície de inundação do alto rio Paraná e áreas adjacentes. Maringá: EDUEM; 2007.

Grill G, Lehner B, Lumsdon AE, Macdonald GK, Zarfl C, Liermann CR. An index-based framework for assessing patterns and trends in river fragmentation and flow regulation by global dams at multiple scales. Environ Res Lett. 2015; 10(1):015001.

Grimm AM, Barros VR, Doyle ME. Climate variability in southern South America associated with El Nino and La Nina events. J Clim. 2000; 13(1):35–58.<0035:CVISSA>2.0.CO;2

Gubiani EA, Ruaro R, Ribeiro VR, Fé UMGS. Relative condition factor: Le Cren’s legacy for fisheries science. Acta Limnol Bras. 2020; 32(e3).

Hartig F. DHARMa: Residual diagnostics for hierarchical (Multi-Level / Mixed) regression models. R package version 0.4.6. 2022.

He F, Zarfl C, Bremerich V, David JNW, Hogan Z, Kalinkat G, Tockner K, Jähnig SC. The global decline of freshwater megafauna. Glob Chang Biol. 2019; 25(11):3883–92.

Hilborn R, Amoroso RO, Bogazzi E, Jensen OP, Parma AM, Szuwalski C, Walters CJ. When does fishing forage species affect their predators? Fish Res. 2017; 191:211–21.

Hoeinghaus DJ, Agostinho AA, Gomes LC, Pelicice FM, Okada EK, Latini JD, Kashiwaqui EAL, Winemiller KO. Effects of river impoundment on ecosystem services of large tropical rivers: embodied energy and market value of artisanal fisheries. Conserv Biol. 2009; 23(5):1222–31.

Hunter ML. Fundamentals of conservation biology. Malden: Blackwell Science; 2001.

Hunter MLJ, Gibbs JP. Fundamentals of conservation biology. Victoria: Blackwell Publishing; 2007.

Johnson PT, Olden JD, Zanden MJV. Dam invaders: impoundments facilitate biological invasions into freshwaters. Front Ecol Environ. 2008; 6(7):357–63.

Junk WJ, Bayley PB, Sparks RE. In: Dodge PD, editor. The flood pulse concept in river-floodplain systems. Proceedings of the International Large River Symposium. Can J Fish Aquat Sci.1989; 106:110–27.

Le Cren E. The length-weight relationship and seasonal cycle in gonad weight and condition in the the lenght-weight relationship and seasonal cycle in gonad weight and condition in the perch. J Anim Ecol. 1951; 20(2):201–19.

Lima FCT, Malabarba LR, Buckup PA, Silva JFP, Vari RP, Harold A, Benine R, Oyakawa OT, Pavanelli CS, Menezes NA, Lucena CAS, Malabarba MCSL, Lucena ZMS, Reis RE, Langeani F, Cassati L, Bertaco VA, Moreira C, Lucinda PHF. In: Reis RE, Kullander SO, Ferraris Jr. CJ, editors. Genera incertae sedis in Characidae. Check list of the freshwater fishes of South and Central America Genera. Porto Alegre: EDIPUCRS; 2003. p.106–69.

Lopes TM, Peláez O, Dias RM, Oliveira AG, Rauber RG, Gomes LC, Agostinho AA. Temporal changes in migratory fish body size in a neotropical floodplain. Oecologia Aust. 2020; 24(2):489–504.

Luz-Agostinho KDG, Agostinho AA, Gomes LC, Júlio Jr. HF. Influence of flood pulses on diet composition and trophic relationships among piscivorous fish in the upper Paraná River floodplain. Hydrobiologia. 2008; 607:187–98.

Marques H, Dias JHP, Perbiche-Neves G, Kashiwaqui EAL, Ramos IP. Importance of dam-free tributaries for conserving fish biodiversity in Neotropical reservoirs. Biol Conserv. 2018; 224:347–54.

McDowall RM, Taylor MJ. Environmental indicators of habitat quality in a migratory freshwater fish fauna. J Environ. Manage. 2000; 25:357–74.

Medeiros ESF, Arthington AH. Fish diet composition in floodplain lagoons of an Australian dryland river in relation to an extended dry period following flooding. Environ Biol Fishes. 2014; 97:797–812.

Mekonnen MM, Hoekstra AY. Sustainability: Four billion people facing severe water scarcity. Sci Adv. 2016; 2(2):1–07.

Meretsky VJ, Atwell JW, Hyman JB. Migration and conservation: Frameworks, gaps, and synergies in science, law, and management. Environ law. 2011; 41(2):447–534. Available from:

Nakatani K, Agostinho AA, Baumgartner G, Bialetzki A, Sanches PV, Makrakis MC, Pavanelli CS. Ovos e larvas de peixes de água doce: desenvolvimento e manual de identificação. Maringá: EDUEM; 2001.

Newbold T, Hudson LN, Hill SLL, Contu S, Lysenko I, Senior RA, Börger L, Bennett DJ, Choimes A, Collen B, Day J, De Palma A, Díaz S, Echeverria-Londoño S, Edgar MJ, Feldman A, Garon M, Harrison MLK, Alhusseini T, Ingram DJ, Itescu Y, Kattge J, Kemp V, Kirkpatrick L, Kleyer M, Correia DLP, Martin CD, Meiri S, Novosolov M, Pan Y, Phillips HRP, Purves DW, Robinson A, Simpson J, Tuck SL, Weiher E, White HJ, Ewers RM, MacE GM, Scharlemann JPW, Purvis A. Global effects of land use on local terrestrial biodiversity. Nature. 2015; 520:45–50.

Oliveira AG, Suzuki HI, Gomes LC, Agostinho AA. Interspecific variation in migratory fish recruitment in the Upper Paraná River: Effects of the duration and timing of floods. Environ Biol Fishes. 2015; 98:1327–37.

Oliveira AG, Lopes TM, Angulo-Valencia MA, Dias RM, Suzuki HI, Costa ICB, Agostinho AA. Relationship of freshwater fish recruitment with distinct reproductive strategies and flood attributes: A long-term view in the upper Paraná River floodplain. Front Environ Sci. 2020; 8:1–11.

Oliveira AG, Angulo-Valencia MA, Rauber RG, Dias RM, Agostinho AA. In: Brink K, Gough P, Royte J, Schollema PP, Wanningen H, editors. Ecology of dourado Salminus brasiliensis (Cuvier 1816): the king of the river. From Sea to Source 2.0: Protection and restoration of fish migration in rivers worldwide. 2ªed. The Netherlands: World Fish Migration Foundation; 2018. p.188–89.

Ortega JCG, Figueiredo BRS, Graça WJ, Agostinho AA, Bini LM. Negative effect of turbidity on prey capture for both visual and non-visual aquatic predators. J Anim Ecol. 2020; 89(11):2427–39.

Ota RR, Deprá GC, Graça WJ, Pavanelli CS. Ten years after “Peixes da planície de inundação do alto rio Paraná e áreas adjacentes”: revised, annotated and updated. Neotrop Ichthyol. 2018; 16(2):e170094.

Pelicice FM, Azevedo-Santos VM, Vitule JRS, Orsi ML, Lima Jr. DP, Magalhães ALB, Pompeu PS, Petrere Jr, M, Agostinho AA. Neotropical freshwater fishes imperilled by unsustainable policies. Fish Fish. 2017; 18(6):1119–33.

Pereira LS, Mise FT, Tencatt LFC, Baumgartner MT, Agostinho AA. Is coexistence between non-native and native Erythrinidae species mediated by niche differentiation or environmental filtering? A case study in the upper Paraná River floodplain. Neotrop Ichthyol. 2017; 15(2):e160142.

Petrere Jr. M. Fisheries in large tropical reservoirs in South America. Lakes & reservoirs: Science, policy and management for sustainable use. 1996; 2(1–2):111–33.

Petrere Jr. M, Agostinho AA, Okada EK, Júlio HF. In: Gido KB, editor. Review of the fisheries in the Brazilian portion of the Paraná/Pantanal basin. Management and ecology of lake and reservoir fisheries. Bodmin: Cornwall; 2002. p.123–42. Available from:

Primack RB. Essentials of conservation biology. Fourth edition. Sinauer Associates, Sunderland, MA; 2006.

Pulliam HR. Sources, sinks, and population regulation. Am Nat. 1988; 132(5):652–61.

R Development Core Team. The R project for statistical computing. 2020. Available at:

Reis RE, Kullander SO, Ferraris Jr. CJ. Check list of the freshwater fishes of South and Central America. Porto Alegre: EDIPUCRS; 2003.

Reynalte-Tataje DA, Nakatani K, Fernandes R, Agostinho AA, Bialetzki A. Temporal distribution of ichthyoplankton in the Ivinhema River (Mato Grosso do Sul State/ Brazil): Influence of environmental variables. Neotrop Ichthyol. 2011; 9(2):427–36.

Ricker WE. Computation and interpretation of biological statistics of fish populations. Bull Fish Res Board Can. 1975; 191:1–382.

Roberto MC, Santana NF, Thomaz SM. Limnology in the upper Paraná River floodplain: Large-scale spatial and temporal patterns, and the influence of reservoirs. Braz J Biol. 2009; 69(2):717–25.

Rocha PC, Santos ML, Souza Filho EE. Alterações no regime hidrológico do alto rio Paraná como resposta ao controle de descargas efetuado por grandes barramentos a montante. In: VIII Encuentro de Geógrafos de América Latina. Santiago-Chile; 2001. p.28–39.

Roque FO, Uehara-Prado M, Valente-Neto F, Quintero JMO, Ribeiro KT, Martins MB, Lima MG, Souza FL, Fischer E, Silva UL, Ishida FY, Gray-Spence A, Pinto JOP, Ribeiro DB, Martins CA, Renaud PC, Pays O, Magnusson WE. A network of monitoring networks for evaluating biodiversity conservation effectiveness in Brazilian protected areas. Perspect Ecol Conserv. 2018; 16(4):177–85.

Rosa RR, Silva JC, Bialetzki A. Long-term monitoring of potamodromous migratory fish larvae in an undammed river. Mar Fresh Res. 2019; 71(3):384–93.

Ruaro R, Conceição EO, Silva JC, Cafofo EG, Angulo-Valencia MA, Mantovano T, Pineda A, de Paula ACM, Zanco BF, Capparros EM, Moresco GA, Oliveira IJ, Antiqueira JL, Ernandes-Silva J, Silva JVF, Adelino JRP, Santos JA, Ganassin MJM, Iquematsu MS, Landgraf GO, Lemes P, Cassemiro FAS, Batista-Silva VF, Diniz-Filho JAF, Rangel TF, Agostinho AA, Bailly D. Climate change will decrease the range of a keystone fish species in La Plata River basin, South America. Hydrobiologia. 2019; 836:1–19.

Sanches PV, Nakatani K, Bialetzki A, Baumgartner G, Gomes LC, Luiz EA. Flow regulation by dams affecting ichthyoplankton: The case of the Porto Primavera Dam, Paraná River, Brazil. River Res Appl. 2006; 22(5):555–65.

Schulte-Hostedde AI, Zinner B, Millar JS, Hickling GJ. Restitution of mass–size residuals: validating body condition indices. Ecology 2005; 86(1):155–63.

Silva FO, Andrade Neto FR, Silva HS, Silva JO, Zaniboni Filho E, Prado IG, Peressin A, Pelicice FM. Recruitment dynamics of a migratory fish in a semiarid river system. Inland Waters. 2020; 10(4):529–41.

Souza Filho EE, Rocha PC, Comunello E, Stevaux JC. In: Thomaz SM, Agostinho AA, Hahn NS, editors. Effects of the Porto Primavera Dam on physical environment of the downstream floodplain. The upper Paraná River and its floodplain: Physical aspects, ecology and conservation. Lieden Backhuys Publisher; 2004. p.55–74.

Stevaux JC, Martins DP, Meurer M. Changes in a large regulated tropical river: The Paraná River downstream from the Porto Primavera Dam, Brazil. Geomorphology. 2009; 113(3–4):230–38.

Stevenson RD, Woods WA. Condition indices for conservation: New uses for evolving tools. Integr Comp Biol.2006; 46(6):1169–90.

Thomaz SM, Bini LM, Bozelli RL. Floods increase similarity among aquatic habitats in river-floodplain systems. Hydrobiologia. 2007; 579:1–13.

Thomaz SM, Parioro TA, Bini LM, Roberto MC, Rocha RRA. In: Thomaz SM, Agostinho AA, Hahn NS, editors. Limnological characterization of ther aquatic environments and the influence of hydrometric levels. The upper Paraná River and its floodplain: Physical aspects, ecology and conservation. Maringá: EDUEM; 2004. p.75–102.

Toïgo C, Gaillard JM, Van Laere G, Hewison M, Morellet N. How does environmental variation influence body mass, body size, and body condition? Roe deer as a case study. Ecography. 2006; 29(3):301–08.

United Nations. World Population Prospects. 2022: The 2022 revision. New York; 2022. Available at:

Vazzoler AEAM. Biologia da reprodução de peixes teleósteos: teoria e prática. São Paulo: EDUEM; 1996. Available at:ção_de_peixes_ teleósteos_teoria_e_prática. [Accessed 12 April 2019]

Venables WN, Ripley BD. Modern applied statistics with S, fourth edition. Springer, New York; 2002.

Wang T, Fujiwara M, Gao X, Liu H. Minimum viable population size and population growth rate of freshwater fishes and their relationships with life history traits. Sci Rep. 2019; 9(3612).

Wantzen KM, Junk WJ. Aquatic-terrestrial linkages from streams to rivers: biotic hot spots and hot moments. Large Rivers. 2006; 16(4):595–611.

Winemiller KO, McIntyre PB, Castello E, Fluet-Chouinard T, Giarrizzo T, Nam S, Baird IG, Darwall W, Lujan NK, Harrison I, Stiassny MLJ, Silvano RAM, Fitzgerald DB, Pelicice FM, Agostinho AA, Gomes LC, Albert JS, Baran E, Petrere Jr M, Zarfl C, Mulligan M, Sullivan JP, Arantes CC, Sousa LM, Koning AA, Hoeinghaus DJ, Sabaj M, Lundberg JG, Armbruster J, Thieme ML, Petry P, Zuanon J, Vilara GT, Snoeks J, Ou C, Rainboth W, Pavanelli CS, Akama A, Soesbergen AV, Sáenz L. Balancing hydropower and biodiversity in the Amazon, Congo, and Mekong. Science. 2016; 351:128–29.

Zaniboni-Filho E, Ribolli J, Hermes-Silva S, Nuñer APO. Wide reproductive period of a long-distance migratory fish in a subtropical river, Brazil. Neotrop Ichthyol. 2017; 15(1):e160135.

Zhao T, Villéger S, Cucherousset J. Accounting for intraspecific diversity when examining relationships between non-native species and functional diversity. Oecologia. 2019; 189:171–83.


Rosa Maria Dias1 , Oscar Peláez1, Taise Miranda Lopes1, Anielly Galego de Oliveira1, Mirtha Amanda Angulo-Valencia1 and Angelo Antonio Agostinho1

[1]    Universidade Estadual de Maringá (UEM), Programa de Pós-Graduação em Ecologia de Ambientes Aquáticos Continentais (PEA),Laboratório de Ecologia e Ictiologia, bloco H90, sala 002, Avenida Colombo, 5790, 87020-900, Maringá, PR, Brazil. (RMD) (corresponding author), (OP), (TML), (AGO), (MAAV), (AAA)

Authors’ Contribution

Rosa Maria Dias: Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Supervision, Validation, Visualization, Writing-original draft, Writing-review and editing.

Oscar Peláez: Data curation, Formal analysis, Investigation, Methodology, Validation, Visualization, Writing-original draft, Writing-review and editing.

Taise Miranda Lopes: Investigation, Methodology, Validation, Visualization, Writing-review and editing.

Anielly Galego de Oliveira: Investigation, Methodology, Validation, Visualization, Writing-review and editing.

Mirtha Amanda Angulo-Valencia: Investigation, Validation, Visualization, Writing-review and editing.

Angelo Antonio Agostinho: Data curation, Funding acquisition, Investigation, Methodology, Project administration, Supervision, Validation, Visualization, Writing-review and editing.

Ethical Statement​

Samples were collected after obtaining all required permissions from the Ministério do Meio Ambiente [Brazilian Environmental Ministry (MMA), the Instituto Chico Mendes de Conservação da Biodiversidade (ICMBio), Sistema de Autorização e Informação em Biodiversidade (SISBIO)] (license number: 22442–1; authentication code: 3263346). This study was approved by the Committee for Ethical Conduct on Animal Use and Experimentation at the Universidade Estadual de Maringá (CEUA; technical advice nº 1420221018/2018).

Competing Interests

The authors declare no competing interests.

How to cite this article

Dias RM, Peláez O, Lopes TM, Oliveira AG, Angulo-Valencia MA, Agostinho AA. Importance of protection strategies in the conservation of the flagship species “dourado” Salminus brasiliensis (Characiformes: Bryconidae). Neotrop Ichthyol. 2022; 20(4):e220046.

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Accepted November 13, 2022 by Ana Cristina Petry

Submitted May 26, 2022

Epub December 19, 2022