The effect of tagging on the swimming performance of rainbow trout as a surrogate for kahawai Arripis trutta

Previous studies indicated that dart tags affect the migration pattern of k ahawai (Australian salmon). Because kahawai cannot be held in experimental swim tunnels, we used rainbow trout Oncorhynchus mykiss as a surrogate spec ies of similar physiology to test the effects of visible implant tags and d art tags on swimming performance. The critical swimming velocity (U-crit) o f untagged rainbow trout, 2.93 +/- 0.12 (SE) body length/s, was unaffected by either tag type. Our findings suggest that altered migration of dart-tag ged kahawai is not due to an acute tag-induced reduction in swimming perfor mance.