Water pollution and its impacts on ecosystems in Jakarta Bay have been extensively studied over the years. Muara Angke is known anecdotally as one of the most heavily polluted parts of Jakarta Bay. In the context of the ongoing debate regarding contamination in the area, we present data on the concentration of metals in green mussels Perna viridis, one of the most popular edible commodities in Jakarta Bay. Histological examination of P. viridis gonads was also performed to demonstrate the direct effects of possible contamination on reproduction in this organism. The concentration of arsenic (As), copper (Cu), nickel (Ni), zinc (Zn), and mercury (Hg) exceeded the upper limits of heavy metal contents in marine biota, whilst only As exceeded the maximum limits of heavy metal contents in processed food, both limits set by Indonesian government. Although the histological observation of gonad tissue after being stained with hematoxylin and eosin revealed some pathologies, high contents of metals in mussels collected in Muara Angke seemed not to affect their reproduction. Ecologically, direct impacts on the tissue of P. viridis will provide vital information needed to predict the health of the species in Muara Angke and the sustainability of the population.

Human activity causes water pollution in Situ Cikaret and Situ Cilodong, in Bogor and Depok, West Java, respectively. The pollutant and toxicant altered the behaviour, anatomy, and physiology of fish in those habitats. This study aimed to analyze the histopathological features of fish gills in Situ Cikaret and Situ Cilodong. The physical and chemical parameters, including pH, temperature, and dissolved oxygen (DO), were measured. Four fish species, Spotted barb fish (Barbodes binotatus), Amazon sailfin catfish (Pterygoplichthys pardalis), Yellow rasbora fish (Rasbora lateristriata), and Louhan fish (Amphilopus citrinellus) were collected. The gills were processed with paraffin, cut into 5 μm, and stained with hematoxylin-eosin. The histological features of Amazon sailfin catfish showed a normal feature, whilst the others showed an abnormality, including hyperplasia, leucocyte proliferation, secondary lamella fusion, vasodilatation, oedema, necrosis, and hypertropia mucus cells, and chloride cells. Although the temperatures, pH, and DO in this study were within the normal values, the abnormality of histological features indicated that Situ Cikaret and Situ Cilodong were polluted.