Sethi SA, Bradley C, Harris F. (2018) Separate tagging versus capture impacts on chum salmon (Oncorhynchus keta) freshwater spawning migration travel time performance? Fisheries Management and Ecology 25: 296-303.
The spawning migration travel times of chum salmon Oncorhynchus keta (Walbaum) fitted with gastrically implanted radio tags versus external spaghetti tags were tested over a short (≈60 river km) and long migration route (≈730 rkm) on the Koyukuk river, Alaska, USA. Using a novel application of statistical arrival curve models to infer travel times for uncaptured fish, migrations by chum salmon not directly handled during the study were also assessed. Results demonstrated negligible differences in travel times within migration routes between fish fitted only with spaghetti tags and fish fitted with radio tags, indicating low impacts on migration travel behavior associated with gastric tags once deployed. Conversely, travel times for unhandled fish as inferred by statistical arrival models may have been 12-24% shorter than those for fish captured with gillnets for tagging. These results suggest that if present, chum salmon migration behavior impacts may be more strongly associated with fish capture than tag deployment.