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                    Research, Society and Development, v. 12, n. 1, e1112139271, 2023
(CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v12i1.39271

Artisanal fishing and fish fauna changes in the lower São Francisco, after seven years
of reduced flow at the Xingó hydroelectric plant
Pesca artesanal e ictiofauna no baixo São Francisco, após sete anos de redução de vazões na
hidroelétrica de Xingó
La pesca artesanal y fauna de peces en el bajo río São Francisco, después de siete años de reducción
de flujo de agua en la central hidroeléctrica de Xingó
Received: 12/13/2022 | Revised: 12/24/2022 | Accepted: 12/25/2022 | Published: 01/02/2023

Emerson Carlos Soares
ORCID: https://orcid.org/0000-0001-5337-5736
Federal University of Alagoas, Brazil
E-mail: soamerson@gmail.com

Rafael Navas†
ORCID: https://orcid.org/0000-0003-1841-1257
Federal University of Alagoas, Brazil
E-mail: rafael.navas@ceca.ufal.br

Emerson Oliveira-Filho
ORCID: https://orcid.org/0000-0002-0485-3508
Federal University of Alagoas, Brazil
E-mail: emersonvinil@yahoo.com.br

Jhonathan Gomes dos Santos
ORCID: https://orcid.org/0000-0001-5463-8876
Federal University of Alagoas, Brazil
E-mail: jhonathan.santos@ceca.ufal.br

Andréa Carla Guimarães de Paiva
ORCID: https://orcid.org/0000-0002-1072-5131
Federal University of Alagoas, Brazil
E-mail: andrea.guimaraes.paiva@gmail.com

Robert M. Hughes
ORCID: https://orcid.org/0000-0003-1308-666X
Oregon State University, USA
E-mail: hughes.bob@amnisopes.com

Themis Jesus Silva
ORCID: https://orcid.org/0000-0001-7443-1063
Federal University of Alagoas, Brazil
E-mail: themisjdasilva@gmail.com

Abstract
Because of hydrological changes in the lower São Francisco River, the objective of this research was to identify sociocultural aspects among artisanal fishers and their understanding of fish species dynamics in the fluvial plain. The
study was conducted in the micro-region of Penedo by using semi-structured interviews. We also collected fish during
low tide using cast nets or gill nets to survey the ichthyofauna of the river plain, identifying the dominant fish species
and their diversity. There is a substantial dependence of fishermen's families on fishing activities, which are
associated with the region's low education level and limited employment opportunities. The remuneration for the
activity is low, which negatively affects the food security of these individuals. There is a perception of changes in the
dynamics and decline in the occurrence of fish species, resulting from decreased flows and destructive fishing
methods. A total of 3,055 individuals comprising 82 taxa and 30 families were collected. The fish fauna on the fluvial
plain is composed mainly of species associated with estuaries, especially near the municipalities of Piaçabuçu and
Penedo. The environmental mitigations of the hydropower plants and the revitalization program were insufficient to
solve the problems in the region.
Keywords: Environmental impacts; Fish fauna; Traditional community; Fluvial plain.

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Research, Society and Development, v. 12, n. 1, e1112139271, 2023
(CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v12i1.39271
Resumo
Devido as mudanças no baixo curso do rio São Francisco, o objetivo do trabalho foi identificar os aspectos
sociocultural da pesca artesanal e compreender a dinâmica das espécies de peixes na planície fluvial. O estudo foi
realizado na microrregião de Penedo através de entrevistas semiestruturadas. Os peixes foram coletados durante a
maré vazante usando malhadeiras e redes de arrasto. O levantamento da ictiofauna da planície fluvial foi realizado
identificando as espécies de peixes dominantes e sua diversidade. Há uma dependência substancial das famílias de
pescadores das atividades pesqueiras, que estão associadas ao baixo nível de escolaridade da região e às limitadas
oportunidades de emprego. A remuneração pela atividade é baixa, o que afeta negativamente a segurança alimentar
desses indivíduos. Há uma percepção de mudanças na dinâmica e declínio na ocorrência de espécies de peixes,
decorrentes da diminuição das vazões e métodos de pesca irracionais. Foram coletados 3.055 indivíduos
compreendendo 82 táxons e 30 famílias. A ictiofauna da planície fluvial é composta principalmente por espécies
associadas aos estuários, principalmente próximo aos municípios de Piaçabuçu e Penedo. As ações ambientais das
hidrelétricas e o programa de revitalização foram insuficientes para solucionar os problemas da região.
Palavras-chave: Impactos ambientais; Ictiofauna; Comunidade tradicional; Planície fluvial.
Resumen
Con los cambios en el bajo río São Francisco, el objetivo del proyecto fue evaluar los aspectos socioculturales en la
pesca artesanal e comprender el flujo de las especies de peces en el plane fluvial. El estudio fue hecho en pequeña
región de Penedo, por intermedio de entrevistas. Las cosechas de los peces fueran hechas en la maré seca con uso de
redes de pesca. La fauna de peces fue identificada, valorando las especies con gran diversidad. Hay fuerte relación de
los pescadores y sus familias con la actividad de pesquerías, además con bajo nivel de escolaridad y poca oportunidad
de empleo. El sueldo es bajo y posee efectos en la seguridad alimentar. Los cambios y la dinámica de rio, además la
depleción de las especies, están relacionadas con la disminución de los flujos de agua y la pesca sin gestión. Fueran
cosechados 3.055 peces de 82 taxones y 30 familias. La fauna de peces en la región, se compone de especies
adjudicadas a la rías, cerca de los ajuntamientos de Penedo e Piaçabuçu. Las acciones em medio ambiente de la
hidroeléctrica y el programa de recuperación del rio São Francisco no tuvieron éxito para solucionar los problemas.
Palabras clave: Médio ambiente; Fauna de peces, Comunidad tradicional; Plane del rio.

1. Introduction
The São Francisco River is Brazil’s largest entirely national hydrographic basin, and is approximately 2,800 km long,
the third-longest in the country. In addition, it flows through three biomes (Mata Atlântica, Cerrado, Caatinga), and is divided
geomorphically into four segments: Upper, Middle, Lower-Middle, and Lower São Francisco (Medeiros et al., 2014; Soares et
al., 2020a). The lower segment extends from Paulo Afonso (BA) to the river mouth and includes the Xingó hydroelectric plant,
located between Sergipe and Alagoas 240 kilometers upriver of the São Francisco River. This region suffers most from the
consequences of the predatory development model imposed on the entire São Francisco River (Marques & Tomáz 2015). The
dams, the deforestation of riparian forests, pollution by domestic and industrial sewage, contamination by pesticides, and the
introduction of non-native species have all contributed to changes in the basin dynamics.
The fish fauna of the São Francisco River comprises many species of environmental, social, and economic
importance, but stocks have been declining because of fishing pressure (Campeche et al., 2011) and reduced flows. Thus,
marine and estuarine species are currently found in areas where freshwater species previously dominated (Soares et al., 2016;
2020b). Salt water currently reaches approximately 10-16 km up the lower São Francisco River, expanding its estuary by 4 km
(Soares et al., 2020a; 2020c). Salinity is most important for governing the distribution of estuarine fish (Blaber, 2000). Some
species migrate to tributaries or the mouth of a river in response to changes in salinity (Cowan, et al., 2013; Cruz et al. 2020).
Artisanal fishermen have been the most affected by the above changes (Nogueira & Sá, 2015; Soares et al., 2020a)
and the lower segment concentrates the largest and poorest fishing population in Brazil (Silva 2014). According to Freitas et al.
(2015), artisanal fishing is of paramount importance for countless families. Besides providing their primary source of income,
fishihg is an important component of their culture and food supply. However, reduced fish populations in all São Francisco
segments have contributed to the impoverishment of these riverside dwellers, which has created one of the most dramatic

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socio-environmental dilemmas in the basin. Artisanal fishermen face many problems, such as housing conditions, health,
education, communication, and territorial disputes (Cardoso, 2009). These problems affect the fishing practiced by riverside
populations which, given the overall unemployment situation that occurs along the São Francisco, has great importance
(Oliveira & Mata-Oliveira, 2020). Therefore, the objective of this study was to identify the socio-cultural insights of artisanal
fishermen and their knowledge of fish fauna dynamics after seven years of reduced flows.

2. Methodology
2.1 Study area
We surveyed artisanal fishermen who live on the banks of the São Francisco River in the municipalities of Penedo
(AL), Neopólis (SE), Santana do São Francisco (SE) and Piaçabuçu (AL) and collected fish at 15 points along the channel
(Figure 1).

Figure 1 - Locations of Penedo, Santana do São Francisco and Neópolis municipalities. The fishes were collected at
15 points (between Long -36.582383 and Lat -10.299611 and Long -36.430666 and Lat -10.412070), in the main
channel of the river, between the upstream and downstream borders of the municipalities of Penedo and Neopólis.
(Dark gray area).

Source: Authors.

2.2 Socioeconomic and environmental data
Artisanal fisher families were interviewed between October 2019 and January 2020. Data collection on
socioeconomic and environmental issues and access to public policies was performed using semi-structured interviews, with a
combination of closed and open questions. Such interviews permit informants to talk about their experiences, based on the

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(CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v12i1.39271
main foci proposed by the researchers, and facilitates free and spontaneous responses from informants (Triviños, 1987). An
adaptation of the free listing technique was also used. Each fisher was encouraged to name the fished/captured species
regardless of purpose, classifying them as frequent or rare/uncommon. Free listing is considered a well-established method,
related to cultural domain boundaries, which assumes that when people list freely, they tend to cite terms in order of
familiarity. Individuals who know more about the requested content list more than those who know less and the terms that are
most remembered indicate their local prominence. The species mentioned frequently exhibit a common knowledge among
individuals, or consensus, within a particular culture or group (Quinlan, 2005).

2.3 Fish sampling and classification
Fish were collected in 2017, 2018, and 2019. The cast net (3.6 meters long, 17 mm mesh between adjacent knots) was
cast 10 times; three consecutive beach seine (22 x 2 m, 8 mm mesh between adjacent knots) hauls were deployed for eight
minutes. The seine was manually pulled by two individuals parallel to the shore and dragged to the bank for removing fish. All
collections were authorized by the Brazilian Authorization System and Information on Biodiversity (SISBIO) under process
numbers 22211-1 and 75591-2 and ethics committee under process number 0024-2020.

3. Results and Discussion
3.1 Fisher socioeconomic profiles
There was a wide range in ages and education levels amongst fishers and their families. The ages of 60% of both male
and female fishers was >40 y, 20% were between 16 and 20 years. All working-age family members, including women, were
fishers, indicating their essential roles in maintaining family incomes. Regarding education level, most men had little formal
education, and most who were studying were school-age children.
Living conditions were basic. All fisher families live in masonry houses, with electricity, garbage collection offered
by the government, and water provided by the Companhia de Abastecimento. However, 50% of homes lacked sewage
collection and 11% lacked basic sanitation systems, resulting in the discharge of untreated sewage directly into the river. Water
was collected from rainwater via cisterns or taken directly from the river. No family had an income above the minimum wage.
The primary public programs available to fishers are the Seguro Defeso (about 90% have a fishing license and receive the
benefit), the Bolsa Família (50% of families), and retirement benefits (25%).

3.2 Fishing activity and fisher perceptions of species dynamics
Fish species that were once common are now rare or non-existent in the Lower São Francisco, and estuarine or coastal
species have increased occurrences 20 to 40 km upriver from the river mouth (Table 1). Fisher perceptions of such changes
were evident, as were their difficulties in surviving by fishing, as was seen in their comments:
"A year ago, I was able to catch 10 to 15 kilos in one day; today I catch 1 kilo, sometimes it's not even enough to eat"
(42-year-old interviewee)
"The fish that we used to catch but that have now disappeared from the São Francisco River were the piaba, mandim,
xira, and surubim, the tubarana has also disappeared from the Lower São Francisco. We can still see it in the backwaters,
jumping in the water. Today in the Lower, there is only tucunaré, piranha, robalo, just those little things; fishing is very weak,
but it's all gone, it's all over." (Retired interviewee)
"The fish that we find very frequently in the São Francisco River are the pirambeba, the tucunaré, the cará-boi, the

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piau branco, the piau preto, robalo, carapeba, and robalo flecha. There are also fish that have disappeared from the river, such
as the piau amarelo, xira, dourada, tubarana, and the mandim, both the yellow and the white, and the pintado is no longer
seen." (38-year-old interviewee).

No longer found

Found more often

Table 1 - Species listed by fishers in order of listing frequency.

Common
name

N° of
listings

Scientific name

Habitat

Robalo

12

Centropomus parallelus, C. undecimalis

Coastal

Tucunaré

10

Cichla monoculus

Non-native

Piau

10

Megaleporinus obtusidens, Schizodon knerii

Native

Piranha

7

Pygocentrus piraya

Native

Tilapia

7

Oreochromis niloticus

Non-native

Carapeba

8

Eugerres brasilianus, Eucinostomus melanopterus,
Diapterus rhombeus

Native - estuary and
freshwater

Pirambeba

6

Serrasalmus brandtii

Native

Bagre

6

Cathorops agassizii

Coastal

Traíra

5

Hoplias microcephalus

Native

Camarão

4

Macrobrachium acanthurus, M. carcinus

Native

Siri

4

Callinectes sp.

Coastal

Pacu

3

Metynnis maculatus

Native

Cara boi

3

Astronotus ocellatus

Non-native

Xira

9

Prochilodus argenteus

Native

Surubim

8

Pseudoplatystoma corruscans

Native

Tubarana

7

Salminus hilarii

Native

Mandi

6

Pimelodus maculatus

Native

Dourado

4

Salminus franciscanus

Native

Curimã

3

Mugil curema

Coastal

Pilombeta

3

Anchoviella vaillanti, A.lepidentostole

Native

Source: Authors.

3.3 Flow effects of the Xingó Hydroelectric Power Plant
During the period of water scarcity (2013 to 2019) several debates and studies were promoted with specialists,
culminating in the creation of the resolution, ANA no 2.081/2017 (National Water Agency). This document made the flow
policy more flexible, promoting facilities for reducing the volume of water used by the hydroelectric plants of the National
Electric System – ONS/Brazil, in the São Francisco River and increased the problems in the lower river, such as: increased
salinity, less dilution of pollutants, formation of new islands, disappearance of marginal lakes and negative effect on the
reproduction of migratory fish. However, after severe droughts in the 2010s, there was a small recovery in the basin with an
increase in flows from 2020, reaching 1.441±444 m3/s (Figure 1).

Figure 2 - Box plot of annual outflows at the Xingó Hydroelectric Power Plant, 2010-2021.

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Source: Authors.

3.4. Fish collected in 2017, 2018 and 2019 in the Penedo reach
A total of 3,055 individuals comprising 82 taxa (80 identified to species and two to genus) and 30 families were
collected. The individuals represented 54 new records (NR) for estuarine or marine species in the São Francisco River basin
(Table 2). Fishes associated with estuaries, especially those in the juvenile phase, were present throughout the entire floodplain
(Table 2), predominating both in terms of abundance (63.56% of the total number of individuals collected) and richness
(72.50% of the total number of species). Moreover, Astronotus ocellatus, Cichla monoculus and Oreochromis niloticus are
non-native species.

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Table 2 - Fish taxa collected on the fluvial plain of São Francisco River estuary. Fish species were classified by preferred
habitat after Froese and Pauly (2015) as freshwater (F), freshwater-estuarine (FE), marine (M), marine-freshwater-estuarine
(MFE) and marine-estuarine (ME). n = number of individuals; NR = new records of occurrence in São Francisco River basin;
H= habitat.

Family

Species

n

Acestrorhynchidae

Acestrorhynchus lacustris (Lütken, 1875)

7

NR

H
F

Achiridae

Achirus lineatus (Linnaeus, 1758)

11

Anostomidae

Megaleporinus obtusidens (Fowler, 1941)

145

F

Schizodon knerii (Steindachner, 1875)

17

F

Ariidae

X

ME

Cathorops agassizii (Eigenmann and Eigenmann, 1888)

2

X

F

Sciades herzbergii (Bloch, 1794)

215

X

MFE

Atherinopsidae

Atherinella brasiliensis (Quoy and Gaimard, 1825)

164

X

ME

Carangidae

Caranx lugubris (Poey, 1860)

2

X

M

Caranx latus (Agassiz, 1831)

24

X

MFE

Centropomidae

Centropomus parallelus (Poey, 1860)

97

X

MFE

Centropomus undecimalis (Bloch, 1792)

72

X

MFE

Astyanax fasciatus (Cuvier, 1819)

167

F

Hemigrammus gracilis (Lütken, 1875)

9

F

Metynnis maculatus (Kner, 1858)

423

F

Moenkhausia costae (Steindachner, 1907)

4

F

Triportheus guentheri (Garman, 1890)

6

F

Astronotus ocellatus (Agassiz, 1831)

10

F

Characidae

Cichilidae

Cichla monoculus (Agassiz, 1831)

105

F

Cichlasoma sanctifranciscense (Kullander, 1983)

20

F

Crenicichla lepidota (Heckel, 1840)

32

F

Oreochromis niloticus (Linnaeus, 1758)

18

Clupeidae

Harengula clupeola (Cuvier, 1829)

9

X

ME

Eleotridae

Dormitator maculatus (Bloch, 1792)

18

X

MFE

Eleotris pisonis (Gmelin, 1789)

64

X

MFE

Engraulidae

Erythrinidae
Gerreidae

Gobiidae

FE

Anchoa januaria (Steindachner, 1879)

4

X

ME

Anchovia clupeoides (Swainson, 1839)

20

X

ME

Anchoviella lepidentostole (Fowler, 1911)

40

Anchoviella vaillanti (Steindachner, 1908)

2

MFE

Cetengraulis edentulus (Cuvier, 1829)

32

Lycengraulis grossidens (Spix and Agassiz, 1829)

15

MFE

Hoplias microcephalus (Agassiz, 1829)

2

F

F
X

ME

Diapterus rhombeus (Cuvier, 1829)

34

X

ME

Eucinostomus argenteus (Baird and Girard, 1855)

42

X

MFE

Eucinostomus melanopterus (Bleeker, 1863)

158

MFE

Eugerres brasilianus (Cuvier, 1830)

256

M

Awaous tajasica (Lichtenstein, 1822)

218

X

FE

Bathygobius soporator (Valenciennes, 1837)

35

X

MFE

Gobionellus oceanicus (Pallas, 1770)

32

X

MFE

Haemulidae

Pomadasys ramosus (Poey, 1860)

4

X

ME

Hemiramphidae

Hemiramphus brasiliensis (Linnaeus, 1758)

17

X

M

Hyporhamphus unifasciatus (Ranzani, 1841)

3

X

ME

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Lutjanidae

Lutjanus alexandrei (Moura and Lindeman, 2007)

57

X

M

Lutjanus analis (Cuvier, 1828)

1

X

ME

Lutjanus cyanopterus (Cuvier, 1828)

10

X

ME

Lutjanus jocu (Bloch and Schneider, 1801)

49

X

MFE

Mugilidae

Mugil curema (Valenciennes, 1836)

37

X

MFE

Mugil curvidens (Valenciennes, 1836)

6

X

M

Paralichthyidae

Citharichthys arenaceus (Evermann and Marsh, 1900)

1

X

M

Citharichthys macrops (Dresel, 1885)

12

X

M

Citharichthys spilopterus (Günther, 1862)

68

X

MFE

X

ME

Polynemidae

Polydactylus virginicus (Linnaeus, 1758)

3

Prochilodontidae

Prochilodus argenteus (Spix and Agassiz, 1829)

2

Scaridae

Sparisoma radians (Valenciennes, 1840)

1

X

M

Scianidae

Bairdiella ronchus (Cuvier, 1830)

12

X

ME

Stellifer brasiliensis (Schultz, 1945)

23

X

M

Stellifer rastrifer (Jordan, 1889)

3

X

ME

Epinephelus itajara (Lichtenstein, 1822)

1

X

ME

X

M

Serranidae

Rypticus randalli (Courtenay, 1967)

1

Serrasalmidae

Pygocentrus piraya (Cuvier, 1819)

43

Serrasalmus brandtii (Lütken, 1875)

126

Sparidae

Archosargus probatocephalus (Walbaum, 1792)

2

Sternopygidae

Sternopygus macrurus (Bloch and Schneider, 1801)

2

Syngnathidae

Microphis brachyurus (Bleeker, 1854)

Tetraodontidae

Colomesus psittacus (Bloch and Schneider, 1801)

F

F
F
X

ME

10

X

MFE

1

X

MFE

Sphoeroides greeleyi (Gilbert, 1900)

3

X

ME

Sphoeroides testudineus (Linnaeus, 1758)

26

X

ME

F

Source: Authors.
4. Discussion
4.1. Fisher socioeconomic profiles
Artisanal fishers are aging throughout the São Francisco basin. Freitas et al. (2015), in research with artisanal fishermen
in the Lower São Francisco, observed that the predominant age was between 40 and 59 years old. According to Rocha et al.
(2011), in the Upper and Middle São Francisco, youth were absent in fishing areas. These studies corroborate our data, where
fishers over 40 years old predominated.
Artisanal fishers are poorly educated in northeast Brazil and throughout the São Francisco basin. Bezerra et al. (2018)
identified in Rio Grande do Norte a predominance of fishers who had not completed elementary school and a significant
percentage of illiterate people. Similarly, Freitas et al. (2015) found for the São Francisco canyons that 30% of fishers were
illiterate and >50% had attended only early elementary school, similar to what we observed. Moreno and Carvalhal (2013)
reported low education levels among artisanal fishers in Ubatuba (SP), as well as insufficient access to infrastructure,
economic benefits, and social inclusion for fishers. Perhaps the most important cause for little formal education is the need to
work, given restricted family incomes. This information reinforces the importance of the “Bolsa Família” program in keeping
children and young people in school, as we observed.
It is noteworthy that approximately 30% of households in the municipalities of Neópolis, Penedo and Santana do São
Francisco, have adequate sanitary sewage (IBGE 2020). Our data differ from those from other studies because most of the
fishers we studied reside in urban areas, which favors access to more public services. However, Bezerra et al. (2018) reported

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the predominance of mud houses lacking basic sanitation in the Lower São Francisco region, close to the river canyons. Also,
Freitas et al. (2015) found that most fishers had masonry houses and access to electricity, but about 30% lacked a running
water supply. The effects of inadequate sewage treatment are amplified by decreased river flows, removal of riparian
vegetation and siloed natural resource management, further reducing the river’s natural purification capacity (Soares et al.
2020a; Cunha, 2015).
Artisanal fishing is not a lucrative profession. According to Freitas et al. (2015), the Seguro Defeso is an income
support program for fishers during periods of fish reproduction. All fishers in their research accessed the benefit and the Bolsa
Família. Bezerra et al. (2018) pointed out that 75% of artisanal fishers in Rio Grande do Norte accessed the Bolsa Família.
However, the fishers that we interviewed indicated that Seguro Defeso payments have been delayed and not received until the
end of fishing ban periods. Bezerra et al. (2018) identified the predominance of low pay among almost all fishers, with
monthly incomes below the minimum wage, similar to what we observed. According to Freitas et al. (2015), fisher monthly
income is uncertain because it depends on the availability of fish and the interference of environmental and climatic factors;
only 11% of their interviewees received > US$ 150.00. In our study, 25% of respondents had a monthly income > US$150.00.
Such incomes do not favor education, sewage treatment, or continuing the profession.

4.2 Fishing activity and fisher perceptions of species dynamics
The fishers that we interviewed observed changes in species dynamics, with the once-common freshwater curimatãpacu (Prochilodus argenteus) being cited as a rare fishing species and the marine/estuarine robalos (Centropomus sp.) and
carapebas (Gerreidae) appearing more frequently. In the studies by Soares et al. (2011) and Soares et al. (2016) there were
already reports of euryhaline species in waters far from the river mouth. This mainly results from the lower river becoming
more brackish, expansion of the saline wedge upriver, and physiological processes of fishes that involve reproduction making
some species better adapted to saline waters and some species less adapted. Soares et al. (2011) reported that fish production
near Penedo was represented by 22 species, of which five were more common: xira, piau (Megaleporinus obtusidens),
pilombeta (Anchoviella vaillantii), robalo, and carapeba (Eugerres brasilianus). Sampaio et al. (2015) found that the most
abundant species caught by fishers were the pilombeta (Anchoviella spp.), with an average of 8 kg/fisherman/day, followed by
the curimatã-pacu or xira, with an average of 5 kg/fisherman/day, and the piaus (Megaleporinus ssp.), with an average of 2.8
kg/fisherman/day. Among the marine species, the authors highlighted the robalos and carapebas. In our survey, fishers
mentioned all these species, especially robalo and carapeba, as the most prominent occurrences in addition to the xira, which
currently is uncommon (Soares et al. 2016; Soares et al. 2020c). Soares et al. (2011; 2016) and Rodrigues et al., (2017) also
reported that robalos and carapebas were among the most captured species around Penedo and Igreja Nova, 40 km from the
São Francisco mouth, corroborating the perceptions of artisanal fishers. Soares et al. (2020b; 2020c) noted an impoverishment
of native and freshwater species in fishers catches in the years 2018 and 2019, during which they report the disappearance of
xiras, pilombetas (Anchoviella sp., Lophiosilurus alexandrii), and pacamãs and piabas (Astyanax sp.)
In addition to range expansions by marine/estuarine fishes, non-natives have been decreasing more recently in lowerriver catches. Barbosa et al. (2017), in a survey in the Lower São Francisco, considered non-native tucunarés (Cichla spp.) and
tilapia (Oreochromis niloticus and Tilapia rendalli) as invasive. Both species were mentioned as common in our interviews
with fishers in the municipality of Sergipe. On the other hand, Freitas et al. (2015) drew attention to non-native species that
were considered by fishers as rare or that have disappeared, such as dourado (Salminus franciscanus), surubim
(Pseudoplatystoma corruscans), and pirá (Conorhynchos conirostris), in addition to those that have decreased as pacu
(Metynnis maculatus), mandi (Pimelodus maculatus), and piau (M. obtusidens, Schizodon knerii). Sampaio et al. (2015), found

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that fishers captured invasive non-native species, with tilapia (Oreochromis sp.), cará-boi (Astronotus ocellatus), and tucunaré
(Cichla monoculus) being the most representative. Tilapia was probably the first invasive species in the region because of its
use in fish farms located along this stretch of the river and tucunaré were introduced for sport fishing in reservoirs, from which
they have escaped or were transported by anglers (Sampaio et al., 2015).
In a preliminary survey near Penedo, Barbosa and Soares (2009) observed that among the native species, several were
very important for human consumption. Therefore, they were targeted for intense fishing, especially the curimatã-pacu,
dourado, surubim, different species of mandi (Pimelodus maculatus and Duopalatinus emarginatus), piau, and traíra (Hoplias
microcephalus). According to Soares et al. (2011), the most valued fish species, included carapeba and piau. Near Penedo and
Neópolis, Barbosa and Soares (2009) collected 16 species, with curimatã-pacu (P. argenteus) as the main catch, followed by
pilombeta (Anchoviella vaillanti), piau, carapebas, cará-boi (Astronotus ocellatus), pacu, and tucunaré. These data suggest that
overfishing endemic species also contributed to reduced natural stocks in the region.
Reduced catches near Neópolis, Penedo and Santana do São Francisco have led to fishers moving to Chinaré (AL,
about 15 km away), Porto Real do Colégio (AL), and Propriá (SE), which are 35 to 40 km distant. Freitas et al. (2015) also
reported that the scarcity of targeted fish on the margins of the São Francisco led to fishers traveling long distances for long
time periods to improve fishing success.
Although fishing is essential to complement fisher family food intake, food insecurity affects about 43% (Freitas et
al., 2015). In Neópolis, food insecurity may be related to low remuneration for the activity. Of the total interviewees, 29%
responded that in the last year they could not afford to have a varied diet and that 14% ate less than they needed. This situation
was reinforced by Bezerra et al. (2018), who observed that most fishers were beneficiaries of the Bolsa Família. However, the
prevalence of food insecurity was high, reaching 67%.
Surveys show that changes in species dynamics resulting from environmental impacts have generated considerable
negative effects among artisanal fishers, hindering fishing, depressing incomes, and compromising food security. Reduced
fishing activity in the Lower São Francisco is reflected in reduced fish diversity and production and low-quality storage and
marketing structures (Lima et al. 2010; Soares et al. 2011). Sampaio et al. (2015) reported that fishing effort is applied to a
reduced number of species, requiring conservation policies to preserve fish stocks. Likewise, Soares et al. (2011) drew
attention to the need for a regional fishery management plan based on the lower volume of fish caught, fishing pressure
focused on specific species, clear fishing decline in the Lower São Francisco, and decreasing incidence of a variety of species
observed.

4.3 Fish fauna observed
Based on secondary data as well as collections performed in the Mid and Lower São Francisco, Barbosa and Soares
(2009) listed 255 fish taxa. The most recent study (Alves et al., 2011) compiled published and unpublished information from
different researchers through January 2011, resulting in a list of 208 species from the source to the mouth. However, those
surveys omitted marine and estuarine species. Barbosa et al. (2017) listed a total of 304 species, including 241 native
freshwater fish species, 35 non-native species, and 28 marine/estuarine species. In our study, 38.5% of the species listed by
Alves et al. (2011) were collected from only 1.4% of the entire length of the São Francisco River, and we recorded 54 new
records for the basin, which correspond to 67.5% of the species identified on the fluvial plain. Brackish water occurs from the
mouth to approximately 10 km upriver (Santos et al., 2013), leading to an estuarine environment, which, includes a partially
stratified salinity gradient.

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To standardize and update habitat guild categories for fishes that use estuaries and other transitional waters, Elliott et al.
(2007) proposed ten categories of ecological use by a given species. That classification was clarified and simplified by Froese
and Pauly (2015). Among the fish species identified on the floodplain of the São Francisco River, the majority (72.50%) are
associated with estuaries or marine (marine-estuarine, marine-freshwater-estuarine and freshwater-estuarine).
The tendency for increased upriver taxa richness is common in coastal rivers (Teixeira et al., 2005; Sarmento-Soares
et al., 2009). However, on the São Francisco River floodplain, greater fish faunal richness was found near the mouth, mainly
because of the presence of species that migrate from the sea. In the São Francisco River floodplain, typical estuarine families,
such as Carangidae, Clupeidae, Engraulidae, Gerreidae and Lutjanidae were common.
Researchers have associated increased taxonomic diversity along rivers with increased habitat heterogeneity (Langeani
et al., 2005) and discharge (McGarvey & Terra, 2016). In the lower 16 km of the São Francisco River, high habitat
heterogeneity results from the presence of several channels, lagoons, and salinity gradients. In addition, many different plant
species such as Rhizophora mangle Linnaeus and Montrichadia linifera Schott, and the macroalgae Elodea sp. create different
microhabitats amongst those waterways.
Some fish families have members that are adapted to the highly variable conditions of estuaries. Indeed, various
estuaries around the world share the same taxa (Cowan et al., 2013). In the present study, the natural pool, near the
municipality of Piaçabuçu, is an important natural nursery for different species of families associated with estuaries.
Mugilidae, Gerreidae and Atherinopsidae predominated in the natural pool, with most individuals being juveniles, respectively
representing 36%, 23% and 15% of the total number of specimens. In the São Francisco River basin, marine and estuarine
species can occur several kilometers upriver from the mouth (Alves et al., 2011, Soares et al. 2020a). Estuarine fish exhibit
diverse degrees of tolerance to changes in salinity (Camargo & Isaac, 2001). Results from studies conducted on Itamaracá
Island in the state of Pernambuco (Guedes et al., 2005) demonstrated that most species are found in all portions of the salinity
gradient. Harengula clupeola was found from freshwater to saline environments.
Among the abundant and very frequent species recorded in the São Francisco, two merit special attention because they
are invasive non-native species: tucunaré and pacu. The former is from the Amazon River basin and the latter is from both the
Amazon and Paraguay River basins. Invading species are often sighted in the lower São Francisco River and are considered
deliberate introductions (Agostinho & Júlio Jr., 1996) as well as the target of local fisheries (Sampaio et al., 2015). Tucunaré
are a serious threat to fish species biodiversity (Alves et al., 2007). Súarez et al. (2001) classified this fish as a generalist
piscivore. It causes changes in the composition and structure of the biological community as well as the mass extinction of
native species (Alves et al., 2007; Leão et al., 2011). The pacu is a small fish (maximum length: 18 cm) with herbivorous
habits (Kullander, 2003). This fish was introduced in reservoirs and rivers in southeastern Brazil, where it is well acclimated
(Pereira et al., 2013) and a commonly caught species (Langeani et al., 2005; Gomes et al., 2008). Because of its peculiar
coloration (silver with numerous black spots along the body and reddish ventral fins), size and rounded shape, the pacu has
tremendous potential for ornamental fish farming (Pereira et al., 2013).
Other non-native invasive species of the São Francisco River basin include the Nile tilapia (Oreochromis niloticus) and
the oscar (A. ocellatus). The characteristics of the Nile tilapia that give it considerable invasive potential include a high
tolerance to environmental changes, broad diet (from algae and zooplankton to fish) and high population growth rate (Attayde
et al., 2007). Populations of this fish can rapidly increase and become dominant, thereby altering the structure of the aquatic
community (Attayde et al., 2007; Vitule et al., 2009). Occurring throughout the entire São Francisco River basin, the Nile
tilapia also occurred in every area of our study, including near Piacabuçu, which demonstrates its tolerance with brackish
waters. Astronotus ocellatus, known as the cara-boi in the Lower São Francisco region, is native to the Amazon River basin in

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Peru, Colombia, and Brazil (Leão et al., 2011). It is known to reduce native biodiversity, including aquatic invertebrates and
fishes (Leão et al., 2011). The oscar was introduced in lakes and reservoirs in northeastern Brazil for aquaculture (DNOCS,
2002). On the São Francisco River floodplain, A. ocellatus occurred in small numbers at only two sampling sites,
demonstrating scarcity and a low frequency of occurrence.
The lower São Francisco River is greatly affected by environmental impacts. The flow from the Xingó Hydroelectric
Power Plant is governed by reservoirs in the upper and middle São Francisco River regions (Três Marias and Sobradinho
dams). There are problems caused by changes in the hydrological regime, such as lower water flow and volume in the lower
course of the river, with a consequent increase of salinity in the region (Soares et al., 2020c). Near the municipality of
Piaçabuçu, Cruz et al., (2020) measured a mean surface salinity of 3.55 ± 1.35 ‰ to 2.71 ± 1.54 ‰; both surface and bottom
waters were defined as brackish. Also, the native fish fauna is overfished, being replace by non-native and euryhaline species,
leading to future extirpation risks. Together, those stressors have altered the ecosystem and human populations (Soares et al.,
2011; Medeiros et al., 2016; Barbosa & Soares, 2011; Barbosa et al., 2017; Barbosa et al., 2018; Soares et al., 2020a).

5. Summary
Human actions, especially in the Lower São Francisco, have negatively affected the lives of artisanal fishers. The
change in fish species occurrence dynamics is perceived by fishermen and is similar to the ichthyofaunal surveys conducted in
the region, emphasizing marine/coastal species becoming increasingly common in our study area.
Difficulties in conducting and maintaining artisanal fishing have had negative economic impacts on families, with low
remuneration for the activity contributing to the high rate of food insecurity. Access to public programs has been restricted,
with delays in receiving the Seguro Defeso, which was aimed to provide a minimum income to families during periods when
fishing is prohibited.
The high potential for environmental degradation and inadequate mitigation programs of the hydropower plants
continue to degrade the São Francisco River basin and riverside human populations.
Monitoring the lower river will continue until 2025, with bimonthly collections and modeling to identify the effects of
flow variation on the entire ecosystem.

Acknowledgments
The work was financed by the São Francisco River Basin Committee (CBHSF) and the Peixe Vivo River Basin
Agency (015/2018), and support from the São Francisco and Parnaíba Valleys Development Company (CODEVASF). RMH
received a Fulbright-Brazil grant.

References
Agostinho, A. A., & Júlio, Jr. H. F. (1996). Ameaça ecológica: peixes de outras águas. Ciência Hoje, 21 (124), 36-44.
Alves, C. B. M., Vieira, F., & Pompeu, P. S. (2011). Ictiofauna da bacia hidrográfica do rio São Francisco. In: Diagnóstico do macrozoneamento ecológicoeconômico da bacia hidrográfica do rio São Francisco/SEDR/DZT/MMA. Brasília: MMA, 226-241.
Alves, C. B. M., Vieira, F., Magalhães, A. L. B., & Brito, M. F. G. (2007). Impacts of non-native fish species in Minas Gerais, Brazil: present situation and
prospects. In: Bert, T. M. (Ed.). Ecological and genetic implications of aquaculture activities. Methods and Technologies in Fish Biology and Fisheries, vol 6,
Springer, Dordrecht. p. 291-314. https://doi.org/10.1007/978-1-4020-6148-6_16
ANA. Agência Nacional de Águas. Resolução nº 2.081, de 4 de dezembro de 2017j. Disponível em: http://arquivos.ana.gov.br/resolucoes/2017/20812017.pdf. Acesso em: 05 fevereiro 2022.

12

Research, Society and Development, v. 12, n. 1, e1112139271, 2023
(CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v12i1.39271
Attayde, J. L., Okun, N., Brasil, J., Menezes, R., & Mesquita, P. (2007). Impactos da introdução da tilápia do nilo, Oreochromis niloticus, sobre a estrutura
trófica dos ecossistemas aquáticos do bioma caatinga. Oecologia Brasiliensis, 11(3), 450-46.
Barbosa, J. M., & Soares, E. C. (2009). Perfil da ictiofauna da Bacia do São Francisco: estudo preliminar. Revista Brasileira de Engenharia de Pesca, 4(1),
155-172. doi: https://doi.org/10.18817/repesca.v4i1.140
Barbosa, J. M., Soares, E. C., Cintra, I. H. A., Hermann, M., & Araújo, A. R. R. (2017). Perfil da ictiofauna da bacia do rio São Francisco. Acta of Fisheries
and Aquatic Resources, 5 (1), 70-90. doi: https://doi.org/10.2312/Actafish.2017.5.1.70-90
Barbosa, J. M., Nunes-Filho, A., Ferreira, A. F., Silva, A. A., & Soares, E. C. (2018). Evolução da atividade agrossilvipastoril na região e Brejo Grande,
Estado de Sergipe: Carcinicultura. Agroflorestalis News, 3(1), 52-60.
Blaber, S. J. M. (2000). Tropical estuarine fishes: ecology, exploitation and conservation. Cleveland Blackwell Science.
Bezerra, D. P., Silva, D. G. K. C., & Silva, J. P. C. (2018). Perfil nutricional e consumo alimentar de pescadores. Journal of the Health Sciences Institute,
36(1), 129-135.
Camargo, M., & Isaac, V. J. (2001). Os peixes estuarinos da região norte do Brasil: lista de espécies e considerações sobre sua distribuição geográfica. Boletim
do Museu Paraense Emilio Goeldi, Serie Zoologia, 17(2):133-157.
Campeche, D. F. B., Balzana, L., Figueiredo, R. C. R., Dos Barbalho, M. R., Reis, F. D. S., & Melo, J. F. B. (2011). Peixes nativos do Rio São Francisco
adaptados para cultivo. Embrapa Semiárido-Documentos (INFOTECA-E).
Cardoso, E. S. (2009). Trabalho
https://doi.org/10.33026/peg.v10i2.1698

e

pesca:

apontamentos

para

a

investigação.

Revista

Pegada

Eletrônica,

10(2),

1-14.

doi:

Cowan, J., Yáñez-Arancibia, A., Sánchez-Gil, P., & Deegan, L. A. (2013). Estuarine nekton. In: Day, J. W. Jr., Crump, B. C., Kemp, W. M., & YáñezArancibia, A. (Eds.). Estuarine Ecology. 2. ed. New York, Wiley-Blackwell, p. 327-355.
Cruz, M. A. S., Silva, C. A., Viana, R. D., Garcia, C. A. B., Coelho Filho, P. A., Praxedes, M. Y. A.V., & Costa, S. S. L. (2020). Salinidade da água na região
do Baixo São Francisco. In: Soares, E. C.; Silva, J. V.; Navas, R. (Orgs.). O Baixo São Francisco: características ambientais e sociais.1 ed. Maceió: EDUFAL,
p. 349-364.
Cunha, C. J. (2015). Regularização da vazão e sustentabilidade de agroecossistemas no estuário do Rio São Francisco. Ceará, Tese. (Doutorado em Geografia)
– UECE.
DNOCS - Departamento Nacional de Obras Contra a Seca. Relatório das atividades desenvolvidas pela coordenação de pesca e aquicultura, durante o ano de
2002. 2002, DNOCS.
Elliott, M., Whitfield, A. K., Potter, I. C., Blaber, S. M. J., Cyrus, D. P., Nordlie, F. G., & Harrison, T. D. (2007). The guild approach to categorizing estuarine
fish assemblages: a global review. Fish and Fisheries, 8, 241-268. doi: https://doi.org/10.1111/j.1467-2679.2007.00253.x
Freitas, L. O., Nogueira, E. M. S., & Moura, G. J. B. (2015). Pesca artesanal no cânion do rio São Francisco: modo de vida, desafios e percepções. In:
Nogueira, E. M. M. S., & Sá, M. F. P. (Orgs.). A pesca artesanal no baixo São Francisco: atores, recursos, conflitos. 1. ed. Petrolina: Editora da Sociedade
Brasileira de Ecologia Humana, p. 44-103.
Froese, R., & Pauly D. FishBase. World Wide Web electronic publication. www.fishbase.org, version (10/2015).
Gomes, J. H. C., Dias, A. C. I. M., & Branco, C. C. (2008). Fish assemblage composition in three reservoirs in the State of Rio de Janeiro. Acta Limnologica
Brasiliensia, 20 (4), 373-380.
Guedes, D.S.G, Vasconcelos-Filho, A.L., & Macedo, R.M. (2005). Ictiofauna do infralitoral adjacente às margens do Canal de Santa Cruz – Itapissuma,
Pernambuco. Boletim Técnico-Científico do CEPENE 13(2): 65-75.
IBGE – Instituto Brasileiro de Geografia e Estatística. Cidades. Disponível em: <https://cidades.ibge.gov.br/brasil/se/neopolis/panorama>. Acesso em: mai.
2020.
Kullander, S. O. (2003). Family Cichlidae (Cichlids). In: Reis, R. E., Kullander, S. O., & Ferraris, C. J. (Eds.). Check list of the freshwater fishes of South and
Central America. Edipucrs, Porto Alegre. p. 605-654.
Langeani. F., Casatti, L., Gameiro, H. S., Carmo, B., & Rossaferes, D. C. (2005). Riffle and pool fish communities in a large stream of southeastern Brazil.
Neotropical Ichthyology, 3(2), 305-311.
Leão, T. C. C., Almeida, W. R., Dechoum, M. S., & Ziller. S. R. (2011). Espécies exóticas invasoras no nordeste do Brasil: contextualização, manejo e
políticas públicas. Centro de Pesquisas Ambientais do Nordeste e Instituto Hórus de Desenvolvimento e Conservação Ambiental (CEPAN), Instituto Hórus de
Desenvolvimento e Conservação Ambiental. Recife, v. 99.
Lima, V. M. M., Santos, M. M., Marques, E., Cesarina, A., & Soares, E. C. (2010). Plano de manejo pesqueiro e comercialização do pescado na cidade de
Penedo, Estado de Alagoas, Brasil. Revista Brasileira de Engenharia de Pesca, 5, 9-22. doi: https://doi.org/10.18817/repesca.v5i3.317
Marques, J., & Tomáz, A. (2015). Ecologia dos pescadores artesanais do baixo São Francisco. In: Nogueira, E. M. M. S.; Sá, M. F. P. (Orgs.). A pesca
artesanal no baixo São Francisco: atores, recursos, conflitos. 1. ed. Petrolina: Editora da Sociedade Brasileira de Ecologia Humana, p. 201-220.

13

Research, Society and Development, v. 12, n. 1, e1112139271, 2023
(CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v12i1.39271
McGarvey, D. J., & Terra, B. D. F. (2016). Using river discharge to model and deconstruct the latitudinal diversity gradient for fishes of the Western
Hemisphere. Journal of Biogeography, 43(7), 1436-1449. doi: https://doi.org/10.1111/jbi.12618
Medeiros, P. R. P., Santos, M. M., Cavalcante G. H., Weber, F. L. S., Silva, W. F. (2014). Características ambientais do Baixo São Francisco (AL/SE): efeitos
de barragens no transporte de materiais na interface continente-oceano. Geochimica Brasiliensis, 28(1): 65-78.
Moreno, L. T., & Carvalhal, M. D. (2013). Trabalhadores do mar: uma discussão sobre as transformações do trabalho do pescador artesanal de Ubatuba/SP.
PEGADA - A Revista da Geografia do Trabalho, 14(1), p. 139-163. doi: https://doi.org/10.33026/peg.v14i1.2178
Nogueira, E. M. S., & Sá, M. F. P. (2015). A pesca artesanal no baixo São Francisco: atores, recursos, conflitos. 1. ed. Petrolina: Editora da Sociedade
Brasileira de Ecologia Humana.
Oliveira, V. S., & Mata-Oliveira, I. Situação Atual da Pesca no Baixo São Francisco: Uma Análise Prospectiva. (2020). In: Soares, E. C.; Silva, J. V.; Navas,
R. (Orgs.). O Baixo São Francisco: características ambientais e sociais.1 ed. Maceió: EDUFAL, p. 226-243.
Pereira, T. S. B., Moreira, R. G., & Batlouni, S. R. (2013). Dynamics of ovarian maturation during the reproductive cycle of Metynnis maculatus, a reservoir
invasive fish species (Teleostei: Characiformes). Neotropical Ichthyology, 11(4), 821-830. doi: https://doi.org/10.1590/S1679-62252013000400010
Quinlan. M. (2005). Considerations for collecting free lists in the field: examples from ethobotany. Field Methods, 17(3), 1-16. doi:
https://doi.org/10.1177/1525822X05277460
Rocha, L. A., Nascimento, N. F., & Ferreira, T. G. Diagnóstico da pesca artesanal no Norte de Minas, Alto/Médio São Francisco. 2011. Disponível em:
<http://www.arquivo.cppnac.org.br/wp-content/uploads/2013/08/Diagn%C3%B3stico-da-Pesca-Artesanal-no-Norte-de-Minas-Alto-M%C3%A9dioS%C3%A3o-Francisco.pdf>. Acesso em: mai. 2020.
Rodrigues, M. L., Santos, R. B., Santos, E. J. S., Pereira, S. M., Oliveira, A., Soares, E. C. (2017). Biologia populacional da carapeba listrada, Eugerres
brasilianus (Cuvier, 1830), próximo à foz do Rio São Francisco (Brasil). Boletim do Instituto de Pesca, v. 43, p. 152-16. doi: https://doi.org/10.20950/16782305.2017v43n2p152
Sampaio, C. L. S., Paiva, A. C. G., & Soares, E. C. (2015). Peixes, pesca e pescadores do Baixo São Francisco, Nordeste do Brasil. In: Nogueira, E. M. M. S.;
Sá, M. F. P. (Orgs.). A pesca artesanal no baixo São Francisco: atores, recursos, conflitos. 1. ed. Petrolina: Editora da Sociedade Brasileira de Ecologia
Humana, p. 105-148.
Santos, E. S, Jennerjahn, T., Leite, T., Medeiros, P .R. P., Souza, W. F. L., & Knoppers, B. A. (2013). Origem da matéria sedimentar no delta-estuarino do rio
São Francisco, AL/SE – Brasil. Geochimica Brasiliensis, 27(1):37-48.
Sarmento-Soares, L. M., Mazzoni, R., & Martins-Pinheiro, R. F. (2009). A fauna de peixes na bacia do rio Jucuruçu, leste de Minas Gerais e extremo Sul da
Bahia. Pan-American Journal of Aquatic Sciences, 4(2):193-207.
Silva, A. P.(2014). Pesca artesanal brasileira: aspectos conceituais, históricos, institucionais e prospectivos. Palmas: Embrapa Pesca e Aquicultura, 32 p.
Soares, E. C., Bruno, A. M. S. S., Lemos, J. M., & Santos, R. B. (2011). Ictiofauna e pesca no entorno de Penedo, Alagoas. Biotemas, 24 (1), 61-67. doi:
https://doi.org/10.5007/2175-7925.2011v24n1p61
Soares, E. C., Paiva, A. C. G., Santos, E. L., Pereira, S. M., Almeida, E. O., & Silva, T. J. (2016). Potential of carapeba Eugerres brasilianus for production.
Latin American Journal of Aquatic Research, 44, 718-725. doi: https://doi.org/10.3856/vol44-issue4-fulltext-7
Soares, E. C., Silva, J. V., & Navas, R. O Baixo São Francisco: características ambientais sociais. Maceió, Edufal. 2020a. 398p.
Soares, E. C., Santos, E. L., Valentim, E., Vasconcelos, V. C., Teodósio, R. F., Paiva, A. C. G., Rial, E. P., & Barbosa, J. M. (2020b). A Ictiofauna do Baixo
São Francisco. In: Soares, E. C.; Silva, J. V.; Navas, R. (Orgs.). O Baixo São Francisco: características ambientais e sociais.1 ed. Maceió: EDUFAL, p. 115139.
Soares, E. C., Silva, C. A., Cruz, M. A. S., Santos, E. L., Silva, T. J., Oliveira, T. R., Perez, E. R., Silva, R. N., & Silva, J. V. (2020c). Expedition on the Lower
São Francisco: An X-ray of fisheries and agriculture, pollution, silting and saline intrusion. Brazilian Journal of Development, 6, 3047-3064.
Súarez, I. R., Nascimento, F. L., & Catella, A. C. (2001). Alimentação do tucunaré Cichla sp. (Pisces, cichlidae) - um peixe introduzido no Pantanal, Brasil.
Corumbá: Embrapa Pantanal. 21p.
Teixeira, T. P., Pinto, B. C. T., Terra, B. F., Estiliano, E. O., Gracia, D., & Araújo, F. G. (2005). Diversidade das assembleias de peixes nas quatro unidades
geográficas do rio Paraíba do Sul. Iheringia. Série Zoologia, 95(4), 347-357. doi: https://doi.org/10.1590/S0073-47212005000400002
Triviños, A. N. S. (1987). Introdução à pesquisa em ciências sociais: a pesquisa qualitativa em educação. São Paulo: Atlas.
Vasconcelos-Filho, A. L., Cavalcanti, E. F., & Souza, S. T. (1994). Composição e distribuição da fauna ictiológica no Canal de Santa Cruz. Revista Nordestina
de Zoologia, 1(1), 247-262.
Vitule, J. R. S. (2009). Introdução de peixes em ecossistemas continentais brasileiros: revisão, comentários e sugestões de ações contra o inimigo quase
invisível. Neotropical Biology and Conservation, 4, (2), 111-122. doi: https://doi.org/10.4013/5123

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