Mean relative densities of all trout by life stages in Panther Creek downstream of mine discharges, relative to reference reaches, at decade intervals.
Fish ≤75 mm in length were considered to be young-of-year (YOY), “Juveniles” are fish 76 to 179 mm in length and are probably 1 and 2 year old fish, and “Adults” are fish >180mm in length. Lengths in the 1993 snorkel survey were visually estimated, and fish lengths in the 2003 and 2013 surveys were measured fork lengths. Error bars show standard deviations. Contrasts between the 1993 visual, snorkel survey and the 2003 and 2013 electrofishing surveys need to be relative to the within-survey reference conditions because the different survey methods had markedly different detection efficiencies (note 20X difference in axis units).