Biomarcadores histológicos em Sciades herzbergii (Pisces, Ariidae) para avaliação de impactos em ambientes estuarinos da Baía de São Marcos, Maranhão

Abstract

RESUMO Neste estudo, objetivou-se avaliar o impacto ambiental em áreas estuarinas da Baía de São Marcos, Maranhão, utilizando-se alterações histológicas nas brânquias e no fígado de Sciades herzbergii como biomarcadores de contaminação aquática. Foram realizadas coletas no período chuvoso (março de 2018) e de estiagem (julho de 2018), em que foram capturados 40 exemplares de S. herzbergii em duas regiões distintas da Baía de São Marcos: A1) Ilha dos Caranguejos (área referência); A2) Terminal de Pesca Industrial de Porto Grande (área potencialmente contaminada). As estações foram georreferenciadas por GPS e, em cada local de captura dos peixes, registraram-se as seguintes variáveis abióticas: temperatura, salinidade, pH e oxigênio dissolvido. Em campo, os organismos foram pesados e medidos, as brânquias e os fígados foram retirados e fixados. Posteriormente, foram mantidos em álcool a 70% até o procedimento histológico padrão. Resultados indicam que as duas áreas são semelhantes em termos de características físico-químicas da água e do sedimento. Todavia, a análise semiquantitativa das alterações histológicas observadas revelou que as brânquias foram o órgão mais afetado nos peixes de A2, indicando que os peixes desse local apresentam danos teciduais maiores resultantes de estresse acentuado por impactos antrópicos.

Impacted estuaries on the Brazilian Amazon coast near port regions influence histological and enzymatic changes in Sciades herzbergii (Ariidae, Bloch, 1794)

“…Regarding length, individuals sampled from PG were larger only in the dry season. Similar results were described by Soares et al (2020) for the same locations: IC fish were heavier than PG fish. The authors attributed these results to the fact that fish from the CI probably had more adequate feeding conditions.…”

“…Fusion of secondary lamellae and epithelial displacement in gills were also described by Sousa et al (2013). According to Soares et al (2020) identified lamellar fusion and epithelial displacement in the tissues of S. herzbergii sampled in São Marcos Bay. Lamellar fusion is a type of injury that occurs as a defense mechanism against direct contact between contaminants and the lamellar epithelium; however, these changes also reduce the respiratory surface, which may result in death (Pereira et al, 2020).…”

“…Environmental conditions may influence fish weight and size (Pinheiro-Sousa et al, 2022). According to Soares et al (2020), exposure of organisms to contaminants and high pollutant concentrations may compromise vital biological, biochemical, physiological, and behavioral systems, leading to redirection of energy to detoxification processes (Sousa et al, 2013). The high traffic of vessels in the port complex is likely causing an increase in toxic substances that might be associated with induction of gill and liver lesions in fish and damage to aquatic health (Castro et al, 2018;Soares et al, 2020).…”

“…The fish known as "guribu" catfish (S. herzbergii) is a species found in several water bodies in Maranhão and is commonly captured in artisanal fisheries and consumed by the Maranhão population, having a great commercial value. S. herzbergii belongs to the Ariidae family and occurs in tropical and subtropical coastal zones, in marine, estuarine and freshwater environments, being generally abundant in coastal waters with muddy and shallow bottoms (Araújo, 1988;Soares et al, 2020;Pinheiro-Sousa et al, 2022). Studies indicate that fish can bioaccumulate high levels of pollutants present in the environment.…”

“…Studies on organ alterations provide punctual information that may reveal potential harm to animal health (Pinheiro-Sousa et al, 2022). A great advantage of using fish histological and enzymatic biomarkers in environmental monitoring is that these parameters allow examining target organs, including the gills and liver, which are responsible for vital functions such as respiration and excretion as well as accumulation and biotransformation of xenobiotics (Soares et al, 2020).…”