The eastern Finland police department has launched an investigation into a massive fish kill in Rautalampi, in eastern Finland’s northern Savo region. On Saturday police collected specimens of the dead fish and also sampled water from streams feeding into the local lake.
Locals have reported large numbers of dead fish washing up on the shores of the lake since Wednesday. The majority of them are said to be roach and bream, but the lifeless shoals also included perch, pike and a few pike perch or zander. On Friday the local daily Savon Sanomat (SS) reported that the number of dead fish ran to tens of thousands.
Residents have been advised not to consume the fish or to feed it to animals. Rautalampi mayor Anu Sepponen also told the paper that residents should avoid swimming in the lake.
Reports of the massive fish kill first surfaced on Wednesday evening, but the scale of the problem only became apparent between Thursday and Friday, SS said.
Disease, algae ruled out as cause
Sepponen and northern northern Savo rescue services fire official Miika Laitinen told SS that the cause of the fish deaths is not yet known. The mayor added that initial information suggested that the fish kill was not due to disease or algal blooms.
Chair of the Rautalampi lake conservation society Pekka Saarikko said he was taken aback by the sight of the dead fish.
"We haven’t seen so many dead fish in this lake in 32 years," he told Yle and added that he'd collected up to 20 dead fish over a 40-metre distance on the lakeshore.
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The municipality has provided several waste containers for residents to dispose of the fish. Originally there was only one in the Jaakonharju district and on Saturday it was half full and emitted a putrid odour.
"We will try to empty the container during the weekend," the mayor commented.
Sepponen said that samples of the lake water and some of the dead fish have been recovered and sent to the northern Savo centre for economic development, transport and the environment (Ely-keskus) for analysis.
Test results are expected by Monday.