Effects of surgically implanted tags and translocation on the movements of common bream Abramis brama (L.)

Abstract

Data collected from wildlife telemetry studies relies on tagging and attachment having minimal impacts on behaviour. Though a widespread technique, relatively few studies evaluate the impacts of differing tagging methods on both welfare and behaviour. Here we use tracking data, collected for other aims, to investigate the impact of inter-peritoneal surgical implantation of acoustic transmitters on the health and behaviour of common bream, Abramis brama (L.). In five separate capture events, the behaviour in terms of distances moved and linear range of newly tagged fish (n=61) were compared to previously tagged fish (n=55) present in the same river at the same time. In the first 5 days post-tagging, newly tagged fish moved significantly further than previously tagged fish. Despite this difference, the linear ranges moved by the two groups of fish were equivalent. During 6–10 days post tagging there was no significant differences between the two groups. Thus, the tagging procedure had short term, but not long term behavioural impacts. In addition, a number of tagged fish were recaptured between 51 and 461 days post-surgery. Recaptured fish appeared to have clean, well-healed incisions and exhibited ‘normal’ behaviour in that they were caught alongside a large number of conspecifics. Three recaptured tagged fish were translocated ∼35km downstream, to ascertain how translocation would affect their behaviour. The translocated fish had a greater linear range than control fish, with all three fish returning to the site of capture within 6 to 24 days, suggesting that common bream can exhibit site fidelity.