External attachment of data storage tags increases probability of being recaptured in nets compared to internal tagging |
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| Authors: | A H Rikardsen†‡ E B Thorstad§ |
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| Institution: | The Norwegian College of Fishery Science, University of Tromsø, N‐9037 Tromsø, Norway;, Norwegian Institute for Nature Research, Polar Environmental Centre, N‐9296 Tromsø, Norway and; Norwegian Institute for Nature Research, Tungasletta 2, N‐7485 Trondheim, Norway |
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| Abstract: | Sea running Arctic charr Salvelinus alpinus and anadromous brown trout (sea trout) Salmo trutta (420–2030 g) tagged with externally attached data storage tags (DST) had a higher total recapture rate (39 of 44, 89%) due to entanglement in bag nets at sea (90% of all recaptures), compared with internally tagged fish (12 of 18, 67%) that were mostly trapped when returning to their home river (75% of all recaptures). The internally tagged fishes therefore spent longer time at sea before recapture (median 33 days) than externally tagged fishes (median 8 days), and more DST‐data were collected. Therefore, in areas with high net fishing intensity, external tagging increases the chances of recapture, but less data may then be recorded by the tags due to a generally shorter period of data sampling. |
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| Keywords: | archival tag migrations radio transmitter tag effects telemetry |
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