Effects of angling and manual handling on pike behaviour investigated by high-resolution positional telemetry H. BAKTOFT, K. AARESTRUP, S. BERG, M. BOEL, L. JACOBSEN & A. KOED Section for Freshwater Fisheries and Ecology, National Institute of Aquatic Resources, Technical University of Denmark, Silkeborg, Denmark M. W. PEDERSEN Department for Informatics and Mathematical Modelling, Technical University of Denmark, Lyngby, Denmark J. C. SVENDSEN Fisheries and Oceans Canada, Central & Arctic Region, Freshwater Institute, Environmental Science, Winnipeg, Manitoba, Canada C. SKOV Section for Freshwater Fisheries and Ecology, National Institute of Aquatic Resources, Technical University of Denmark, Silkeborg, Denmark Abstract Human disturbances such as angling and manual handling may have long-term effects on the behaviour of pike, Esox lucius L., an ecologically important species. Using continuous high-resolution positional telemetry, this study compared the swimming activity of handled and unhandled pike in a small lake. Pike pre-equipped with acoustic transmitters were angled and exposed to a handling protocol including measurements of length and mass. Pike not recaptured constituted an unhandled control group. Results demonstrated that the handling protocol caused temperature-dependent changes in pike activity, with higher temperatures leading to lower activity of the recaptured pike. The effects, however, were transitory and not detectable after 48-h post-release. These findings indicate that pike are relatively resilient to handling and quickly resume pre-handling activity. KEYWORDS: acoustic telemetry, angling, catch-and-release, Esox lucius, temperature. Introduction Being a widespread top-level predator in many freshwa- ter ecosystems (Craig 1996) as well as a popular target for recreational and commercial fisheries (Pierce et al. 1995; Arlinghaus & Mehner 2004), the potential impacts of anthropogenic disturbances on pike, Esox lucius L., must be well documented to facilitate qualified manage- ment of this resource. Management regimes of pike pop- ulations often include size-specific restrictions on the removal of individuals for consumption, which in turn necessitates release of captured individuals outside the allowable size range. Knowledge about how pike is affected by catch-and-release thus seems warranted. Correspondence: Henrik Baktoft, Section for Freshwater Fisheries and Ecology, National Institute of Aquatic Resources, Technical University of Denmark, DK-8600 Silkeborg, Denmark (e-mail: hba@aqua.dtu.dk) doi: 10.1111/fme.12040 © 2013 John Wiley & Sons Ltd Fisheries Management and Ecology, 2013, 20, 518–525 518 Fisheries Management and Ecology