Effects of liming on fisheries

• Published in: Philosophical Transactions of the Royal Society of London. B, Biological Sciences
• Format: Article in Journal/Newspaper
• Language: English
• Published: The Royal Society 1984
• Subjects: Arctic; Salvelinus alpinus
• Online Access: http://dx.doi.org/10.1098/rstb.1984.0076; https://royalsocietypublishing.org/doi/pdf/10.1098/rstb.1984.0076

Liming measures for treating acidified surface waters have been carried out in Sweden for a trial period with the aid of Government grants. The aim was to study whether lime treatment was a possible method of protecting waters of special value for fisheries, nature conservation or recreational uses. In all waters where liming resulted in a sufficient and durable pH increase, the fish started to reproduce again, even if the populations were composed of very few and old individuals at the time of treatment. In waters with weak recruitment one or more rich year classes appeared after liming. Restocking of extinct populations of Arctic char ( Salvelinus alpinus )and brown trout ( Salmo trutta ) after lime treatment resulted in self-reproducing populations. In populations with intact recruitment, individual growth rates were generally not affected but in weak populations with fast individual growth rates, growth rates decreased after liming. Liming of acidic inlet waters that have high concentrations of aluminium led to heavy mortality in fish farms as did acid spring runoff flowing into a lime treated lake. Rainbow trout introduced into lakes shortly after liming also experienced high mortality. Lime treatm ent can never be a definite cure for acidified waters, but may protect fish populations in lakes with long turnover times in areas with relatively low acid deposition. Periods of high runoff in streams, rivers and lakes with short turnover times were difficult to treat with lime. In areas with a high acid load and acidified watersheds, liming of lakes and running waters will not prevent acid groundwater with elevated concentrations of toxic metals from entering surface waters.