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Pereira NS, Sial AN, Pinheiro PB, Freitas FL, Silva AMC. Carbon and oxygen stable isotopes of freshwater fish otoliths from the São Francisco River, northeastern Brazil. AN ACAD BRAS CIENC 2021; 93:e20191050. [PMID: 33759955 DOI: 10.1590/0001-3765202120191050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 01/16/2020] [Indexed: 11/21/2022] Open
Abstract
Fish otoliths store geochemical and isotopic signatures that can be used as proxies for environmental conditions in ecological investigations. We investigated the δ13C and δ18O of otoliths of four freshwater fish species (Astronotus ocellatus, Serrasalmus brandtii, Plagioscion squamosissimus, and Cichla ocellaris) from the Moxotó Reservoir in the São Francisco River, Brazil. The enriched δ13C signatures that distinguish A. ocellatus from other species could be caused by dissolved inorganic carbon (δ13CDIC) in reservoir waters. Macrophytes growing along the reservoir margins would favor photosynthetic uptake of 12C, leading to enriched δ13CDIC incorporated into the otoliths of those fish. Otolith δ18O signatures appear to reflect water column preferences, in which species preferentially inhabiting surface waters (such as S. Brandtii) show more enriched values (due to high surface evaporation ratios), while bottom water species show depleted δ18O values. Our results represent the first investigation of the isotopic compositions of fish otoliths in freshwater environments in the São Francisco River, and shed light on the interpretation of isotopic information stored in otoliths and how they can be used to infer the ecological strategies of freshwater fish.
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Affiliation(s)
- Natan S Pereira
- Universidade do Estado da Bahia, Departamento de Ciências Exatas e da Terra, Rua Silveira Martins, 2555, 41150-000 Salvador, BA, Brazil.,Universidade Federal de Pernambuco, Departamento de Geologia, NEG-LABISE, Av. Prof. Moraes Rego, 1235, 50670-000 Recife, PE, Brazil
| | - Alcides N Sial
- Universidade Federal de Pernambuco, Departamento de Geologia, NEG-LABISE, Av. Prof. Moraes Rego, 1235, 50670-000 Recife, PE, Brazil
| | - Patrícia B Pinheiro
- Universidade do Estado da Bahia, Colegiado de Engenharia de Pesca, Departamento de Educação, Rua da Gangorra, 503, 48608-240 Paulo Afonso, BA, Brazil
| | - Fabrício L Freitas
- Universidade do Estado da Bahia, Colegiado de Engenharia de Pesca, Departamento de Educação, Rua da Gangorra, 503, 48608-240 Paulo Afonso, BA, Brazil
| | - Adriana M C Silva
- Universidade do Estado da Bahia, Colegiado de Engenharia de Pesca, Departamento de Educação, Rua da Gangorra, 503, 48608-240 Paulo Afonso, BA, Brazil
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Parasites of Cambeva davisi (Siluriformes: Trichomycteridae) from the Cascavel stream, Neotropical area. Biologia (Bratisl) 2021. [DOI: 10.2478/s11756-020-00564-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Abstract
Degradation and habitat loss of natural grasslands in Southern Brazil has a negative impact on native organisms, potentially including the composition of anuran helminth communities. Here, we characterized the richness, abundance, taxonomic composition, prevalence and intensity of helminth infection in four anuran species. Host anurans were collected in 34 ponds (19 in native grasslands with livestock and 15 in agricultural cultivation) from the highland grasslands in the Brazilian states of Santa Catarina and Paraná. Our results showed a significant difference between native grasslands with livestock and agricultural cultivation regarding the structure of helminth communities for the hosts Aplastodiscus perviridis and Pseudis cardosoi. We also found a greater prevalence and intensity of infection in anurans in areas of agricultural cultivation than in native grasslands with livestock. We found that the environmental descriptors (local and landscape) seem to explain most of the differences in anuran parasitism recorded between native grasslands with livestock and agricultural areas. Thus, we emphasized that the loss of grassy habitat due to conversion to agricultural cultivation can alter helminth communities in anurans, with further work needed to understand the mechanisms involved.
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