PIT‐tagging Italian spined loach (Cobitis bilineata): Methodology, survival and behavioural effects

Abstract

The Italian spined loach (Cobitis bilineata) is an elongated, small‐sized (<12 cm) spined loach native to northern Italy, Slovenia and Croatia. As for loaches in general, little is known about the individual movements of this loach in nature. Passive integrated transponders (PIT‐tags) are small (typically 7–32 mm), relatively cheap and allow tracking of individual fish movements and behaviour. A fundamental assumption in animal telemetry is that the performance of a tagged animal does not deviate substantially from its natural performance. Although PIT‐tagged fish often display high survival and tag retention, the effect varies between species and contexts, and few studies have looked at behavioural effects of PIT‐tagging. Here we demonstrate a PIT‐tagging methodology for spined loaches, and compare survival, activity and provoked escape response (maximum swimming speed) between tagged and control fish. We also track tag retention in the tagged fish. Italian spined loaches tagged with 12 mm PIT‐tags displayed high tag retention and no extra mortality, and no effects of tagging on activity or maximum swimming speed were observed. The tag‐to‐fish weight and length ratios in our study ranged from 2% to 5% and from 10% to 16%, respectively, and we conclude that PIT‐tagging, within these ratios, appears suitable for Italian spined loach.

Survival and swimming performance of a small-sized Cypriniformes (<em>Telestes muticellus</em>) tagged with passive integrated transponders

“…The maximum swimming speeds found are in agreement with swimming capacities reported for Leuciscidae species in North America (Leavy and Bonner, 2009). No difference in maximum swimming speed between PIT tagged fish and control fish also corroborates the result from escape response-based swimming tests in spined loaches (Nyqvist et al, 2022), bullheads (Knaepkens et al, 2007) and lampreys (Mueller et al, 2006).…”

“…Treatment fish were tagged with a Passive integrated transponder (PIT-tag; Biomark; 12 mm * 2.1 mm; 0.10 g). The scalpel technique involved an incision of 2-4 mm on the ventral side of the fish, offset slightly from the centre and anterior to the pelvic fins (Bolland et al, 2009;Nyqvist et al, 2022). The tag was pushed forward in the abdominal cavity to align with the fish's body.…”

“…Most PIT-tag effects studies on small-sized fish focus on survival and tag retention, typically but not always, showing high survival and high retention rates (Clark, 2016;Vollset et al, 2020). Potential behavioural and performance effects caused by PIT tags, on the other hand, are much less investigated despite their importance for fish behavioural studies in a natural environment (Nyqvist et al, 2022). Here, swimming performance represents an important ecological trait involving both physical and behavioural components that can be quantified in the laboratory (Tudorache et al, 2013).…”

“…Here, swimming performance represents an important ecological trait involving both physical and behavioural components that can be quantified in the laboratory (Tudorache et al, 2013). The effects of PIT tagging on the swimming performance of small-bodied fish have been studied in only a handful of species, where tagging has not been shown to affect either prolonged swimming performance (Newby et al, 2007;Ficke et al, 2012) or maximum swimming speeds (Nyqvist et al, 2022;Swarr et al, 2022). Not only the tag but also the tagging procedure (i.e., handling and tagging technique) can have potential effects on the tagged animal (Brown et al, 2011).…”

Navigating the drought: upstream migration of a small-sized Cypriniformes (Telestes muticellus) in response to drying in a partially intermittent mountain stream

“…Before tagging, fish were anaesthetised with clove oil (Aromlabs, USA; approximately 0.2 mL clove oil per litre of water). An incision of 2-4 mm was made on the ventral side of the fish, slightly offset from the centre and frontal to the pelvic fins, before the tag was inserted and pushed forward in the abdomen (Nyqvist et al, 2022;Schiavon et al, 2023). Once the fish had been tagged, they were measured for fork length and weight and allowed to recover in tanks filled with river water.…”