Mean daily mobility estimates for smallmouth bass Micropterus dolomieu from mark‐recapture (47·5±12·5 m) were less than from conventional telemetry (77·1±10·6 m). The relationship developed in a respirometer between the activity transmitter and swimming speed (r2=0·99, P < 0·001, n=6) when applied to field activity data estimated mean daily movement at 27 408±4085 m, i.e. >100 times mark/recapture or telemetry estimates. Using these estimates in the activity parameter of a bioenergetics model resulted in different model outputs. These results highlight the potential underestimates in activity associated with using traditional mark‐recapture and locational telemetry and reaffirm that fish expend a significant portion of their activity budgets undertaking localized movements.