Bioaccumulation of total mercury in Platanichthys platana (Regan, 1917), an invasive zooplanktivorous fish in the billings complex (Upper Tietê River Basin, SP)

Abstract

Total mercury (Hg) levels in water, zooplankton and in the invading fish Platanichthys platana were studied in the Billings Complex, in order to understand the transfer of the total Hg to higher trophic levels. Samples were collected at four sites with different levels of eutrophication, at the dry and rainy seasons of 2014. A total of 93 specimens of P. platana were analyzed. During the rainy season the Grande River site was the only one that showed total Hg values above the legal standards (0,004 mg.L-1) in the water, while in the zooplankton, it was detectable only in the Central Body in the same season. Total Hg observed in fish varied between 0,04 e 0,29 μg.g-1, and highest values in fish were found at the Grande River site. The analysis of covariance (ANCOVA) showed an influence of the sites (p=0,000) and total length (p = 0.008) on Hg concentrations, suggesting an influence of the environmental conditions on Hg bioaccumulation in the fishes. The successful invasion of P. platana in the Billings Complex suggests that this species is acting as an additional element for the transfer of the total Hg to higher trophic levels.