Effects of tagging on migration behaviour, survival and growth of hatchery‐reared Atlantic salmon smolts

Abstract

The effects of four different tagging methods (PIT, anchor T‐tag, Carlin tag and dummy radio transmitter) on survival, behaviour and growth of Atlantic salmon smolts during their downstream migration were examined in semi‐natural circular channels during a natural migration period in spring. Survival of smolts was high and tagging wounds healed well in all tagging groups. Tag loss rates were generally low, being the highest (2.5%) in the dummy radio transmitter group. Total length and body mass of the tagged and untagged smolts did not differ at the end of the experiment. Migration activity of smolts generally showed similar patterns among the treatments. However, Carlin‐tagged smolts started their migration slightly later than the PIT‐tagged fish, and smolts tagged with Carlin tag or dummy radio transmitter showed less overall migration activity than fish with PIT tag.

Survival of undersized plaice (Pleuronectes platessa), sole (Solea solea), and dab (Limanda limanda) in North Sea pulse-trawl fisheries

“…However, tagging effects are thought to be negligible, at this methodology is applied in many studies with none to very limited observed mortality (e.g. Huusko et al, 2016). Additionally, control fish may not have been representative of the treatment fish due to the acquisition process pre-selecting for the least damaged survivors.…”

Variations in migration behaviour and mortality of Atlantic salmon smolts in four different hydroelectric facilities

“…Downstream movement activity of smolts increases as the river temperature rises, usually close to or above 10°C (Lundqvist et al, 2010; Ruggles, 1980). This increase in swimming activity together with rising temperature was evident also in smolts of hatchery origin released in the river (Karppinen et al, 2014) and was discernible even in fish farm experimental conditions (Huusko et al, 2016; Martin et al, 2012). The hatchery smolts used in this study were well smoltified according to their external appearance and behaviour.…”

Retention of passive integrated transponder tags in hatchery brook trout: Effect of tag size, implantation site, and double tagging

“…Other PIT‐tagging studies with salmonids have used some, but not all, of these approaches to measure growth, and never simultaneously, to the best of our knowledge. Commonly, mean size through time has been compared between tagged groups and untagged controls, either alone (Huusko et al, 2016; Prentice et al, 1990; Sigourney et al, 2005) or in conjunction with: (a) growth rate from mean size of tagged and untagged fish (Bateman & Gresswell, 2006; Tiffan et al, 2015) or individual growth rate in weight of tagged fish only (Acolas et al, 2007; O'Donnell & Letcher, 2017; Ostrand et al, 2011; Richard et al, 2013). Comparison of individual growth rates of tagged and untagged fish provides a detailed examination of tagging effects (e.g., Larsen et al, 2013), but this approach is comparatively rare given the methodological challenges of identifying individuals in untagged control groups.…”