Prolonged swimming speeds of female pink salmon (55 cm, 1879 g) were determined in a 27-cm diameter steel tunnel at 20 + or – 1 oC. The speeds were corrected for cross-sectional blocking effect of the fish by comparing tailbeat frequencies for the same velocities in the tunnel and in an open flume. The mean maximum sustained speed (10-h test time) was 1.12 m/s (2.04 l/s). Compared with sockeye salmon, pink salmon could only perform at approximately 80% of the level of prolonged speed achieved in the same tunnel by sockeye of comparable size.