The effects of nanosilver on northern pike

Abstract

Nanosilver (nAg) is an effective anti-microbial agent that is being increasingly used in consumer products. With such an expansive list of products incorporating nAg, the risk of environmental release is high. Studies testing the impacts of nAg have shown ranging effects on the physiology of fishes, but to date no significant impacts to growth in natural settings at environmentally-relevant exposure levels over long term (months to years) periods have been documented. A collaborative study was performed at the IISD –Experimental Lakes Area to evaluate whole-ecosystem changes in the presence of environmentally relevant levels of nAg. I evaluated changes in Northern Pike size-at-age before, during, and after nAg additions to a treatment lake (Lake 222) and compared the findings to a reference lake (Lake 239). Significant declines in fork length and weight at age over time were observed across all year groups, with the most notable declines occurring in the year 4 and 5 age groups. There were no similar changes observed in the reference lake. Body condition did not change with nAg additions. Despite reduced populations and no apparent changes in the availability of the prey community, growth of Northern Pike declined. The results of this study strongly suggest that nAg has a direct inhibitory effect on Northern Pike growth, likely caused by a reduced conversion efficiency