Suitability of surgically implanted 8‐mm passive integrated transponder tags for small‐bodied fishes

Abstract

Innovative tools that benefit conservation are critical as freshwater fishes are lost at unprecedented rates. Mark‐recapture methods can characterize population demographics and life‐history traits of diverse fishes, but suitable techniques for tagging for individual recognition of small‐bodied fishes are rare. Passive integrated transponder (PIT) tag technology may facilitate the tagging of small fishes and early life stages of larger species. However, relatively little research has evaluated the suitability of these small (8.4 × 1.4 mm) tags for many groups of small fishes. Tag loss (retention and survival) and growth of individuals implanted with PIT tags relative to control and sham treatments were compared for eight fishes of differing morphologies. Additionally, the utility of cyanoacrylate to improve tag retention was tested on a subset of taxa. Fish of each species were equally divided and randomly assigned to one of three treatment groups (handled [control], surgical incision [sham], or surgical incision and PIT tag implantation [PIT]). During the 42‐d study period, mortalities and expelled tags were counted daily and growth was measured weekly. Researchers can generally expect little tag loss and uncompromised growth rates for a variety of small‐bodied fishes; however, initial fish length was related to the magnitude of physiological effects for some taxa (i.e., blacknose dace Rhinichthys atratulus, johnny darter Etheostoma nigrum, juvenile white sucker Catostomus commersonii). Relatively poor survival (<80%) was observed for two benthic species: johnny darter and blacknose dace, often when incision wounds became inflamed before healing. Prevalent tag loss for johnny darter, tadpole madtom Noturus gyrinus, and a dorsal‐laterally compressed cyprinid can be reduced by closing the wounds with cyanoacrylate, but with substantially increased mortality rates. This research demonstrates the broad applicability of PIT tagging technology for ecological studies of small‐bodied fishes and alleviates many concerns when surgically implanting tags into several fishes.

Suitability of passive integrated transponder tags and a new monitoring technique for at-risk madtoms (Noturus spp.)

“…Similar to other short-term tagging studies involving madtoms (Johnston & Smithson 1999, Musselman et al 2017, D'Amico 2018, Schumann et al 2020, there was no apparent effect of the PIT tags on frecklebelly madtom survival. Retention of tags following their surgical implantation has been rarely reported to be below 90% for madtoms (but see Schumann et al 2020), and zero ejections, as observed in the current study, have been reported for similarly sized madtoms (Musselman et al 2017, D'Amico 2018. Surgically implanted tags are seemingly applicable to diverse studies of patterned madtoms, as re searchers can rea- sonably expect rapid healing of the surgical wounds and minimal tag loss.…”

“…Few studies have experimentally evaluated the suitability of small PIT tags for studies involving small-bodied catfishes (Musselman et al 2017, Schumann et al 2020, and to our knowledge, no research has evaluated their suitability for frecklebelly madtom or any other of the patterned madtoms (subgenus Rabida). Similar to other short-term tagging studies involving madtoms (Johnston & Smithson 1999, Musselman et al 2017, D'Amico 2018, Schumann et al 2020, there was no apparent effect of the PIT tags on frecklebelly madtom survival.…”

“…Few studies have experimentally evaluated the suitability of small PIT tags for studies involving small-bodied catfishes (Musselman et al 2017, Schumann et al 2020, and to our knowledge, no research has evaluated their suitability for frecklebelly madtom or any other of the patterned madtoms (subgenus Rabida). Similar to other short-term tagging studies involving madtoms (Johnston & Smithson 1999, Musselman et al 2017, D'Amico 2018, Schumann et al 2020, there was no apparent effect of the PIT tags on frecklebelly madtom survival. Retention of tags following their surgical implantation has been rarely reported to be below 90% for madtoms (but see Schumann et al 2020), and zero ejections, as observed in the current study, have been reported for similarly sized madtoms (Musselman et al 2017, D'Amico 2018.…”

“…No fish < 30 mm total length (TL) were tagged because earlier investigations showed low survival of smaller individuals of a closely related species (Schumann et al 2020). Although not directly applicable to field studies, food was withheld for 36 h before PIT tag implantation to allow for consistent gut evacuation among individuals.…”

Tag retention in and effects of passive integrated transponder tagging on survival and swimming performance of a small‐bodied darter

“…The survival of E. spectabile in the study drastically declined after 60 days to 56% survival, which was attributed to a poor diet. Schumann et al (2020) tagged Johnny darter Etheostoma nigrum Rafinesque 1820 with 8 mm tags in a 42 d study and reported 63% survival and 70% retention.…”