Estudos na conservação de espécies de peixes do rio Santo Antônio, bacia do rio Doce
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Data
2019-08-01
Autores
Siqueira, Hatus de Oliveira
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Universidade Estadual Paulista (Unesp)
Resumo
Alterações ambientais provocadas por atividades agropecuárias, barramentos, expansão urbana e poluição figuram entre as principais ameaças à conservação da ictiofauna no País. Na bacia do rio Doce, por exemplo, 9 de suas 70 espécies encontram-se listadas na portaria MMA 445/2014. O rompimento da barragem de rejeitos de mineração de Fundão, ocorrido em 2015, pode ter ocasionado uma piora no estado de conservação de algumas dessas espécies, bem como a inclusão de outras nas categorias de ameaças. Assim, torna-se imperativo a realização de estudos e ações para a conservação desses peixes. Entre as áreas reconhecidas como relevantes para a conservação da ictiofauna do rio Doce destaca-se a bacia do rio Santo Antônio. O presente trabalho teve como objetivo realizar estudos focados em biologia básica e reprodutiva para fornecer subsídios a conservação das espécies ameaçadas de extinção endêmicas da bacia do rio Doce. As coletas foram realizadas no rio Santo Antônio no Município de Ferros – MG. Foram coletados espécimes de Henochilus wheatlandii, Steindachneridion doceanum e Brycon opalinus os quais foram encaminhados ao ICMBio/CEPTA e mantidos em tanques e viveiros com renovação constante de água. Entre as espécies capturadas, H. wheatlandii foi a mais abundante com indicativos de possuir uma população saudável. As demais espécies foram menos abundantes e possivelmente podem estar em declínio na região. Os juvenis de H. wheatlandii se mostram sensíveis a variações de temperatura e a infestação por Ichthyophthirius multifiliis. Por outro lado, os indivíduos adultos das três espécies coletadas se adaptaram rapidamente as condições de cativeiro. No presente estudo foram caracterizados aspectos de diferenciação sexual secundária, motilidade espermática e análise cromossômica das espécies. Além disso, foi elaborado uma proposta de unidade de conservação para proteger os habitats necessários a manutenção de quatro espécies ameaçadas de extinção.
Environmental changes caused by agricultural activities, buses, urban sprawl, and pollution are among the main threats to ichthyofauna conservation in the country, as an example, 9 out of 70 species of the Doce river basin are listed in MMA 445/2014 ordinance. The Fundão mining tailings dam rupture of 2015 may have led to aggravation in the conservation status of some of these species, as well as the inclusion of others in higher threat categories. Thus, it is imperative to develop studies and actions for these fish conservation. Among the areas of Doce river basin that are recognized as relevant for ichthyofauna conservation, Santo Antônio river basin takes a place of highlight. Our work aimed to develop studies focused on species basic reproductive biology to provide support for the conservation of endangered endemic species of the Doce river basin. The collections were done in Santo Antônio river, located in Ferros – MG. Specimens collected of Henochilus wheatlandii, Steindachneridion doceanum, and Brycon opalinus were sent to ICMBio / CEPTA and kept in tanks with constant water renewal. Among the species captured, H. wheatlandii was the most abundant, with indications of having a healthy population. The other species were less abundant and possibly may be declining in the region. The H. wheatlandii juveniles showed to be sensitive to temperature variations and infestation by Ichthyophthirius multifiliis. On the other hand, the adults of the other three species adapted quickly to captivity conditions. In our study, we characterized aspects of secondary sexual dimorphism, sperm motility and chromosomal analysis of the species. In addition, a conservation unit proposal was developed to protect the habitats needed for the maintenance of four threatened species.
Environmental changes caused by agricultural activities, buses, urban sprawl, and pollution are among the main threats to ichthyofauna conservation in the country, as an example, 9 out of 70 species of the Doce river basin are listed in MMA 445/2014 ordinance. The Fundão mining tailings dam rupture of 2015 may have led to aggravation in the conservation status of some of these species, as well as the inclusion of others in higher threat categories. Thus, it is imperative to develop studies and actions for these fish conservation. Among the areas of Doce river basin that are recognized as relevant for ichthyofauna conservation, Santo Antônio river basin takes a place of highlight. Our work aimed to develop studies focused on species basic reproductive biology to provide support for the conservation of endangered endemic species of the Doce river basin. The collections were done in Santo Antônio river, located in Ferros – MG. Specimens collected of Henochilus wheatlandii, Steindachneridion doceanum, and Brycon opalinus were sent to ICMBio / CEPTA and kept in tanks with constant water renewal. Among the species captured, H. wheatlandii was the most abundant, with indications of having a healthy population. The other species were less abundant and possibly may be declining in the region. The H. wheatlandii juveniles showed to be sensitive to temperature variations and infestation by Ichthyophthirius multifiliis. On the other hand, the adults of the other three species adapted quickly to captivity conditions. In our study, we characterized aspects of secondary sexual dimorphism, sperm motility and chromosomal analysis of the species. In addition, a conservation unit proposal was developed to protect the habitats needed for the maintenance of four threatened species.
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espécies ameaçadas, banco genético, unidades de conservação, endemismo, endangered species, genetic bank, conservation units, endemism