Figure 1.

Swimming performance of chub (Leuciscus cephalus) following exposure in submerged cages at two sites on the river Lambro, Italy: a relatively clean site (Merone) or a polluted site (Brugherio). Results from (a) June 2001, (b) September 2001 and (c) January 2002. The graphs show mean (±s.e.m.) critical swimming speed (U_crit) as measured twice, with the second swim test (T2) measured 40 min following fatigue in the first swim test (T1), and the corresponding repeat performance ratio (U_crit T2/U_crit T1). In all cases, n=6. Asterisk, significant difference between T1 and T2 for that river site in that campaign; dagger, significant difference between the two sites for the relevant variable in that campaign; Mer, Merone; Brug, Brugherio.