Dear all of colleagues
There was a case of mass fish mortality about two weeks ago in a river in Aceh Province. Only mahseer fish (Tor spp) was dead both juvenile and adult fish. Based on our observation and personal communication with local residents showed that there is two possible caused: (1) illegal gold mining, and (2) volcano activity. We have been sampled water, sediment, death fish, live fish, snails and freshwater algae. We consider to analyze the samples for mercury, cyanide, natrium and sulfide. But the results will be available in a couple of days later.
Our speculation is probably this is caused by sulfide or mercury contents in the waters. My question is there possible for mercury (heavy metals) or sulfide to kill the fish in short times (about 3-7 days)? and Is there any similar cases in other places or countries?
Thank you for your comments
here are a few things that i would consider also in formulating a hypothesis; a) if there was an instantaneous mass mortality of fish, it would suggest that there was an out-of-the-ordinary event that triggered it. regular (illegal) gold mining might not be that event- unless there was an extraordinary spill event that took place. b) there is only one species of fish killed, not others (?) - what sets these fish apart from other fish in biological terms (?); c) what is farming like in the area and the catchment basin, and have you considered looking into pesticide run-off (e.g. DDT) which is also a known cause for massive fish kills.
pesticides used to kill fish in a shorter time effectively than other mercury or heavy metals used in conventional way illegal miners. similar case occurred in Poland
Possibility of illegal gold mining is still in doubt, because they are still using conventional means (concentrations of mercury and other heavy metals is used for the separation of gold from mines in ppt).
The possibility of volcanic activity. if you do on the upstream side of the Leuser, the reason this is one of them, but not the main factor.
I agree with Emil Siregar because there were reports of mass mortality of fishes in India in enclosed freshwater bodies. The causative agent was pesticides from agricultural fields nearby and the dead fishes were usually carps.
Dear all, thank you for your comments, our initial results showed that the sulfide concentration was higher than 0.05 ppm, the lower (
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