Abstract:
Mercury is one of dangerous pollutant in the aquatic environment and can be
accumulated in aquatic organism. High concentrations and long time exposure of
mercury causes on death fish. This research aims to understand the behaviour and
changes occur in the gill structure of the Hemibagrus nemurus Blkr. that were treated
with mercury (Hg) in sublethal concentrations (0.490 ppm). Total fishes use in this
study was 20, 10 fishes for control and 10 fishes for treatment. After being treated for
96 hours, fish behavior, morphological and histological structure of the gills was
studied. The results indicated that the treated fishes shown abnormality, such as
hyperactive become weaken and finally die within 96 hours. The gills of the treated
fishes was red pale, while that of the control light red. Histological study shown that
there were abnormality in the gills tissue, such as hyperplasia, hypertrophy, fusion of
secondary lamella, lifting of epithelial cells, epithelium rupture, hemorrhage,
hypertrophy of the chlorid cells and necrosis. Based on data obtained it can be
concluded that the LD50 of mercury (0.490 ppm) negatively affect the gill of
H. nemurus
