Can fish gill anomalies be used to assess water quality in freshwater Neotropical systems?

Abstract

Gill anomalies in two fish species (Geophagus brasiliensis and Astyanax bimaculatus) were compared among three freshwater systems with different water quality: one eutrophic river, one eutrophic reservoir, and one oligotrophic reservoir. The raised hypotheses are that reservoirs with low water quality (eutrophic) have fish with more gills anomalies compared with reservoirs with high water quality (oligotrophic), and that the more stable environmental conditions of eutrophic rivers have fish with better healthy conditions than eutrophic reservoirs that have lesser stable environmental conditions. Gills of 36 adult individuals of G. brasiliensis and 23 of A. bimaculatus collected during the winter 2008 and winter 2009 were examined, and the proportions of occurrence of nine histological alterations were compared for the two species among the three systems using a binomial t test for independent samples. Histological changes in fish gills that are reversible and unspecific, such as epithelial lifting, interstitial edema, leukocyte infiltration, hyperplasia of the epithelial cells, lamellar fusion, and vasodilatation were common in both fish species in the three systems. However, lamellar aneurism, which is a more serious and often irreversible anomaly, and lamellar blood congestion occurred only in fish from the two reservoirs. Alternatively, necrosis occurred more in fish from the river. Fish gill anomalies in both species did not differ between the two reservoirs, despite having different water quality. We rejected the hypothesis that reservoirs with lower water quality have fish with more gill injuries compared with high water quality reservoirs. Moreover, the eutrophic river seems to affect differently the healthy condition of fish species, compared with the eutrophic reservoir.

European sea bass gill pathology after exposure to cadmium and terbuthylazine: expert versus fractal analysis

“…Indeed fish gill histology is widely used in environmental surveys or in experimental trials with toxic substances (Mallatt, ; Pawert et al ., , Pandey et al ., ; Gomes et al ., ; Nascimento et al ., ). Previous studies (Mallatt, ; Pawert et al ., , Pandey et al ., ; Gomes et al ., ; Nascimento et al ., ), with the notable exception of Pinkney et al . (), assessed gill lesions in a qualitative manner or quantified specific lesions in terms of frequency of occurrence without attempting to quantify their relative tissue extension or to assess their discriminative power, as was performed in this study.…”

“…Nevertheless, fractal analysis resulted in 100% sensitivity as well, but it completely failed both to discriminate unexposed, with lower specificity than expert analysis, and to clearly discriminate between the two toxic exposure classes, although evidence of significant differences among fractal measures were found during the present survey. Indeed fish gill histology is widely used in environmental surveys or in experimental trials with toxic substances (Mallatt, 1985;Pawert et al, 1998, Pandey et al, 2008Gomes et al, 2012;Nascimento et al, 2012). Previous studies (Mallatt, 1985;Pawert et al, 1998, Pandey et al, 2008Gomes et al, 2012;Nascimento et al, 2012), with the notable exception of Pinkney et al (1989), assessed gill lesions in a qualitative manner or quantified specific lesions in terms of frequency of occurrence without attempting to quantify their relative tissue extension or to assess their discriminative power, as was performed in this study.…”

“…Fish gills are appropriate but nonspecific biomarkers, as this tissue shows limited responses to a wide range of environmental physicochemical stimuli (Mallatt, 1985;Takashima & Hibiya, 1995;Pawert et al, 1998;de Oliveira Ribeiro et al, 2002;Dezfuli et al, 2003Dezfuli et al, , 2006Giari et al, 2006Giari et al, , 2007Giari et al, , 2008Pandey et al, 2008;Gomes et al, 2012;Nascimento et al, 2012). Nevertheless, Mallatt (1985), in his statistical review of fish gill structural changes induced by toxicants and other irritants, stated that most types of gill lesions were more frequent during lethal, than sublethal exposure tests.…”

“…Fish gills respond to a wide range of environmental physicochemical stimuli in a limited manner; and accordingly they are considered general biomarkers (Mallatt, 1985;Dezfuli et al, 2006;Giari et al, 2007;Gomes et al, 2012;Nascimento et al, 2012). In fact, fish gill condition is extensively used in environmental studies and ecotoxicological trials, although gill lesions are normally only qualitatively or semiquantitatively assessed (Mallatt, 1985;Pawert et al, 1998;Pandey et al, 2008;Gomes et al, 2012;Nascimento et al, 2012). Despite the usefulness of evaluating gill condition in pathology studies a standardized method to quantify histological changes is still lacking.…”

Assessment of the impact of chlorophyll derivatives to control parasites in aquatic ecosystems

“…The possible cause of mortality could be a toxic effect of chlorophyllin on the gills of the fish. Gomes et al (2012) conducted studies on A. bimaculatus in which they monitored anomalies of fish gills to assess fresh water quality. One of the stressors studied was the presence of chlorophyll derivatives.…”