Karyotype Analysis and Mapping of the 18S and 5S Ribosomal Genes in Astyanax fasciatus (Teleostei, Characiformes) from Paranapanema River Basin

AbstractPopulations of Astyanax paranae, Astyanax fasciatus and Astyanax altiparanae collected from the Pindorama and Lopei streams (upper Paraná river basin, Brazil) were cytogenetically studied, checking for chromosomal differentiation and the evolutionary trend in the three species. Forty-eight chromosomes (8m + 20sm + 10st + 10a) were observed in both populations of Astyanax paranae. Astyanax fasciatus exhibited 50 chromosomes (8m + 18sm + 10st + 14a, Pindorama stream; 8m + 14sm + 12st + 16a, Lopei stream). The diploid number for A. altiparanae was 50 chromosomes in both populations (6m + 30sm + 4st + 10a). The three studied species exhibited multiple AgNORs with differences among the populations of A. paranae and A. fasciatus. Regarding the heterochromatin distribution, interpopulational differences were observed in the three species. The data of the present study demonstrate that both A. paranae and A. fasciatus exhibit karyotypical interpopulational differences more conspicuous than A. altiparanae populations, probably due to the characteristics that restricted both the A. paranae and the A. fasciatus to the upper portion of the streams, leading to the fixation of different chromosomal rearrangements in the populations. However, the absence of conspicuos interpopulational karyotypical differences in A. altiparanae suggests a gene flow between both populations. In the present study, the role of the streams as an environment which maintains the diversity of fish with different genetic pools became evident.

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Environmental diagnosis of water quality in situ and ex situ in streams in Upper Paraná River Basin, Brazil

10.21203/rs.3.rs-559449/v1 ◽

2021 ◽

Author(s):

Vandressa Raquel Lucas Poloni Meira ◽

Elicléia Maria de Souza Silva ◽

Lucilene Finoto Viana ◽

Bruno do Amaral Crispim ◽

Luiza Flávia Veiga Francisco ◽

...

Keyword(s):

Water Quality ◽

River Basin ◽

Native Species ◽

Ex Situ ◽

Forest Fragments ◽

Composition And Structure ◽

Astyanax Fasciatus ◽

Plant Bioassay ◽

Agricultural Areas

Abstract The aim of this study was to (i) evaluate water quality using limnological parameters in three streams belonging to the Ivinhema River basin, (ii) investigate the composition and structure of the landscape around the locations sampled and their possible contribution to changes in water quality, (iii) investigate genotoxicity in fish in situ as environmental bioindicators, and (iv) evaluate the cytotoxic and genotoxic potential of water through bioassays in animal and plant models. A total of seven fish species were sampled in situ as bioindicators of environmental toxicogenetic damage: Astyanax fasciatus, Astyanax lacustris, Cyphocharax modestus, Moenkhausia forestii, Piabina argentea, Psellogrammus kennedyi, and Hypostomus ancistroides. Four types of nuclear and one cytoplasmic alteration were observed, with nuclear invagination being the most frequent. Animal bioassays showed five types of nuclear and one cytoplasmic alteration. In the plant bioassay, a reduction in germination and cell division was observed, indicating the cytotoxic and genotoxic effects of the water for Allium cepa cells. Thus, genotoxic alterations in fish and plant bioassays may reflect the different types of land use and cover around streams and the conversion of forest fragments into agricultural areas, mainly due to the expansion of sugarcane crops. The evaluation of the toxicogenetic status of the three streams is essential to emphasize the need to create projects to recover the native vegetation cover, which would improve the quality of the habitat and ensure the permanence of native species.

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Ichthyofauna of the Mamanguape river basin, Northeastern, Brazil

Biota Neotropica ◽

10.1590/1676-0611-bn-2017-0452 ◽

2018 ◽

Vol 18 (3) ◽

Cited By ~ 2

Author(s):

Leonardo Oliveira-Silva ◽

Telton Pedro Anselmo Ramos ◽

Yuri Gomes Ponce Carvalho-Rocha ◽

Katherine Morais Porto Viana ◽

Raizze da Costa Avellar ◽

...

Keyword(s):

River Basin ◽

Poecilia Reticulata ◽

Fish Fauna ◽

Arid Area ◽

Northeastern Brazil ◽

Main River ◽

Astyanax Fasciatus ◽

The Family ◽

Dominance Pattern ◽

Semi Arid

Abstract: The Mamanguape River Basin is located in a peripheral semi-arid area of South America, with its headwaters and middle reaches running through the Caatinga (from wetter to drier) and its lower reaches through the Atlantic Forest. The objective of this study was to inventory the fish fauna of the Mamanguape river basin through a comprehensive sampling and to discuss its ichthyofaunal dominance pattern. Sampling was conducted between 2015 and 2016 at 38 points throughout. The main river course was sampled at 18 fixed points during two expeditions (dry and wet seasons) using traw nets, cast nets, and dip nets, with a standardized effort. The tributaries were sampled during the dry season at 20 points using an adaptaptation of the AquaRAP methodology. A total of 32 freshwater fish species belonging to 26 genera, 16 families and six orders were recorded, predominantly from the order Characiformes and the family Characidae. Astyanax fasciatus had widest distribution and greatest abundance in the basin. Siluriformes were the second most prevalent order, with five species recorded. Cichla cf. monoculus, Poecilia reticulata and Oreochromis niloticus were non-native records for the basin. Apareiodon davisi, an Endangered species, was recorded.

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