Condition and Sperm Characteristics of Perch Perca fluviatilis inhabiting Boreal Lakes Receiving Metal Mining Effluents

Abstract

One of the world's largest, but low-grade, sulfide nickel deposits in northeastern Finland has been exploited by a bioheapleaching technology since 2008. Bioheapleaching is a relatively new, cost-effective technology, but humid climate, e.g., in boreal temperate environments, causes challenges to the management of the water balance in the ore heaps with wide catchment area, and the mining effluents have caused substantial metal and salting contamination of the receiving waterbodies. In our study, the impacts of metal-extracting bioheapleaching mine effluents on muscle and liver element concentrations, body condition, liver and testes mass, and sperm count and motility of male perch Perca fluviatilis were analysed. Liver, testes, and carcass mass of perch in relation to their length were lower in the mining-impacted lakes than in the reference lake, which may be due to the metal contamination, food availability, and energy demand under multistressor conditions. The sperm counts of the males in the mining-impacted lakes were lower, but the endurance of their sperm motility was longer than the endurance of sperm of the reference males. These findings suggested that the condition and sperm characteristics of perch were altered in lakes receiving metal mining effluents. Measured variables seem to be useful indicators for metal mining impacts on freshwater fish but only if high natural variation in these characteristics can be controlled by multiyear monitoring scheme.

Toxicity of Mining-Contaminated Lake Sediments to Lumbriculus variegatus

“…The Mn accumulation in TV sediments was generally at the same level as in the reference sediments. Mn has been observed to accumulate to chironomids (Woelfl et al, 2006) and perch (Perca fluviatilis) (Karjalainen et al, 2020) in metal-contaminated lakes and also to whitefish (Coregonus lavaretus) eggs and larvae under experimental conditions (Arola et al, 2017). In our study, Mn concentrations of L. variegatus correlated positively with the sediment concentrations although in some test sediments (e.g., in the HLW setup of the high hazardous group in the TV) the accumulation was surprisingly low in relation to the sediment concentration.…”