Retention of loop,monel, and passive integrated transponder tags by wild,free‐ranging Lake Sturgeon (Acipenser fulvescens Rafinesque, 1817)

Tagging or marking of fish is instrumental to fisheries biologists and managers seeking to distinguish groups of fish, track movement or migration patterns, and monitor population characteristics. However, tag loss can inhibit the ability of biologists and managers to reach these objectives. The ability of Lake Sturgeon to live for long periods of time and reach large sizes, in combination with their dynamic spawning activity, requires tags to be retained under a variety of environmental and physically demanding conditions. This study evaluated tag retention of loop, monel, and passive integrated transponder (PIT) tags on wild, free‐ranging Lake Sturgeon in Lake Huron and the St. Clair – Detroit River System. Lake Sturgeon in this study were double‐tagged with both a PIT tag under one of the three anterior‐most dorsal scutes and an external tag (loop or monel) at the base of the dorsal fin. Fish were at large for up to 16 years. Overall, tag loss for PIT tags was 1% followed by monel tags at 12% and loop tags at 36%. Tag loss for loop tags was higher when the initial length of Lake Sturgeon tagged was smaller. Tag loss for monel tags increased with time at large but was not related to length at initial tagging. Monel tags left behind abrasion marks when attached to smaller Lake Sturgeon. PIT tag retention was higher than reported in previous studies that tagged other sturgeon species in different body locations. Monel tag retention was higher than other external tag types evaluated in previous studies while loop tags had similar retention rates to external tag types. Most previous studies on tag retention of sturgeon species were of shorter duration and conducted in laboratory settings, therefore loop tags may have performed more favorably during studies under short term laboratory settings. Results of this study suggest that PIT tags inserted below dorsal scutes represent a viable option for long‐term tracking of Lake Sturgeon. Monel tags attached at the base of the dorsal fin also seem to be a viable option relative to other external tag types, but should be limited to larger sturgeon as they can leave behind abrasion marks.     

Effects of tag type on red snapper Lutjanus campechanus tag retention,growth and survival under hatchery conditions

Management of red snapper stocks is one of the most controversial issues in the Gulf of Mexico fisheries. Fish tagging programs can help to address many management issues if an appropriate tag is selected. In the study three types of tags were tested to determine tag retention and effects on red snapper growth and survival. Hatchery‐produced juveniles (43.7 ± 5.6 g) were either not tagged or given: internal anchor tags anchored in the abdominal cavity; passive integrated transponders (PIT) tags injected into the body cavity; or metal self‐piercing fish tags clamped around the dentary bone. Fish were stocked at 25 m^?3 in three replicate circular tanks/tag type, and fed a commercial feed for a 150 days period. Fish survival did not differ by treatment. Average weight gains after 150 days were similar. Tag retention differed by treatment (P = 0.0002), with 100% retention of PIT tags, 98.4 ± 2.8% retention of jaw tags, and 90.4 ± 1.6% retention of internal anchor tags. Loss of internal anchor tags occurred primarily within the first month. Inflammation was frequently observed at the internal anchor tag insertion site. Irritation and cell proliferation was sometimes observed in areas around the jaw tags.     

Evaluation of PIT‐tagging in cyprinids

Laboratory and field experiments were used to investigate how different marking procedures, with 23 mm PIT (passive integrated transponders) – tags, affected mortality, body condition and tag expulsion in small roach Rutilus rutilus and rudd Scardinus erythrophthalmus (117 to 163 mm total length). In a laboratory experiment mortality was low (≤ 6%) and only occurred among fishes that had their incision closed with sutures. The latter also had a specific growth rate that tended to be lower than the fish tagged without sutures. The different marking procedures did not adversely affect the body condition of fishes either in the laboratory experiment (after 37 days) or in the field experiment (up to 369 days). No tag expulsions were observed among laboratory fishes PIT‐tagged without sutures. Marking without the use of sutures to close the incision, appears to be the most appropriate PIT tagging procedure for small cyprinids.     

The potential use of PIT telemetry for identifying and tracking crayfish in their natural environment

A method for tracking crayfish and other benthic animals in rivers and streams, based on passive integrated transponder (PIT) technology, using a portable detector was investigated. The effect of implanting crayfish with PIT tags and the efficiency of the PIT tag detector system at locating tags is described. In a laboratory study 30 signal crayfish Pacifastacus leniusculus (>33.7 mm carapace length) were internally implanted with PIT tags (12-mm long×2.1-mm diameter) and 30 crayfish matched for size and sex were kept as controls and maintained for 6 months. Tagging had no significant effect on survival, moulting or growth of crayfish, and tag retention was 100%. The reader unit consists of an antenna coil mounted on a pole and designed to be moved over the streambed to search for tagged crayfish. Efficiency testing indicated that more than 80% of tags were identified and located when hidden within different stream microhabitats.     

Evaluation of VIE and PIT tagging methods for juvenile cyprinid fishes

Retention and mortality associated with visible implant elastomer (VIE) and passive integrated transponder (PIT) tagged juvenile chub [ Leuciscus cephalus (L.)], dace [ Leuciscus leuciscus (L.)] and roach [ Rutilus rutilus (L.)] were evaluated. PIT tag retention (96.6–100%) was higher than VIE over the 6-month duration of the experiment. VIE retention was significantly better in the head (96.3–98.8%) than in the fins (78.8–90.9%) the first month after tagging, but the opposite was found after 6 months (head = 21.5–57.5%; fins = 77.2–88.8%). Survival was not significantly different from controls for any treatment, except dace tagged with 23-mm PIT (significantly influenced by mass of fish at tagging) and sham PIT tagged dace, because of initial losses. PIT tags are recommended as the most suitable method for tagging individual juvenile chub, dace and roach based on high retention and survival. VIE implantation in the head (studies < 30 days) and fins (studies > 30 days) could provide a cheap, batch-marking alternative, provided retention rates are monitored.     

Effects of surgically implanted PIT tags on growth, survival and tag retention of yellow shortfin eels Anguilla australis under laboratory conditions

This study evaluated the effects of surgically implanted passive integrated transponder (PIT) tags on growth rate, survival and tag retention of yellow shortfin eels Anguilla australis with an initial mean mass of 101 g. There were no significant differences in body mass, total length, specific growth rate and survival between tagged and untagged A. australis in a 108 day laboratory trial. This tagging method was very reliable, with a tag retention of >95%.     

Tag retention and mortality of adult Atlantic salmon Salmo salar gastrically tagged with different sized telemetry transmitters

A batch of 1 sea winter pre‐spawning adult Salmo salar from the Bush river in Northern Ireland, U.K., were gastrically tagged with large (13 mm diameter) and small (9 mm diameter) dummy acoustic telemetry tags alongside untagged control fish. Survival differed between control and tagged fish and the estimated probability of survival by the end of the study for control fish with no tag was 0·94, small tags was 0·90 and large tags was 0·72. Tag loss through regurgitation was slightly higher for fish tagged with larger tags than for fish tagged with smaller tags and the estimated probability of tag loss for fish with a small tag was 0·10 and for large tags was 0·14.     

Evaluation of passive integrated transponder tag retention from two tagging locations in juvenile pallid sturgeon

Population augmentation and propagation of pallid sturgeon (Scaphirhynchus albus) have been a focus of scientists since the mid‐1990s. Various tag types have been used to gain a better understanding of population characteristics, stocking success, and movement patterns. Passive integrated transponder (PIT) tags have been consistently used since the inception of recovery efforts to mark age‐1 and older pallid sturgeon. This tag has been successfully used with other sturgeon species, and tagging protocols for pallid sturgeon were developed in response to those successes. Tag retention rates in pallid sturgeon have been reported as variable or unknown and there has been no formal study to determine PIT tag retention in pallid sturgeon, particularly with age‐1 individuals that are propagated in hatcheries to be stocked into the wild. The objective was to evaluate retention rates of PIT tags inserted into the operculum and along the base of the dorsal fin of age‐1 pallid sturgeon (total fork length [FL] range = 214–358 mm). Tagged sturgeon (n = 80) were held in a large holding tank and inspected for tag loss twice a month for a total of 189 days. Final tag retention was 83% for tags inserted into the operculum and 85% for tags inserted near the dorsal fin. Tags shed from the operculum were from smaller fish (mean FL = 265 mm) and losses occurred during the first 60 days of the experiment. Tags shed from the dorsal site were predominantly from larger individuals (mean FL = 305 mm) and losses were continual throughout the experiment. Future research should determine size‐specific tag retention rates so that hatcheries can maximize retention in either tag placement location.     

Predicting the factors influencing the inter- and intraspecific survival rates of riverine fishes implanted with acoustic transmitters

Biotelemetry is a central tool for fisheries management, with the implantation of transmitters into animals requiring refined surgical techniques that maximize retention rates and fish welfare. Even following successful surgery, long-term post-release survival rates can vary considerably, although knowledge is limited for many species. The aim here was to investigate the post-tagging survival rates in the wild of two lowland river fish species, common bream Abramis brama and northern pike Esox lucius, following their intra-peritoneal double-tagging with acoustic transmitters and passive integrated transponder (PIT) tags. Survival over a 2-year period was assessed using acoustic transmitter data in Cox proportional hazards models. Post-tagging survival rates were lowest in the reproductive periods of both species, but in bream, fish tagged just prior to spawning actually had the highest subsequent survival rates. Pike survival was influenced by sex, with males generally surviving longer than females. PIT tag detections at fixed stations identified bream that remained active, despite loss of an acoustic transmitter signal. In these instances, loss of the acoustic signal occurred up to 215 days post-tagging and only during late spring or summer, indicating a role of elevated temperature, while PIT detections occurred between 18 and 359 days after the final acoustic detections. Biotelemetry studies must thus always consider the date of tagging as a fundamental component of study designs to avoid tagged fish having premature end points within telemetry studies.     

Low Rates of PIT-Tag Loss in an Insectivorous Bat Species

The rate of loss of tags used to mark individuals is an important consideration in wildlife research and monitoring. Passive integrated transponder (PIT) tags (or microchips) generally have high retention rates; however, tag loss rates for small mammals such as insectivorous bats are poorly understood. We double-marked a population of Gould's wattled bats (Chalinolobus gouldii) with forearm bands and PIT tags (with the injection site sealed with surgical adhesive) in January and February 2020 to determine rates of subsequent tag loss over the short- (1–2 months) and medium- (13–14 months) term. Loss of PIT tags occurred in 4 (2.7%) of 146 recaptured individuals, all within 2 months of microchipping. We also recorded 1 occurrence of band loss 11 months after banding. Our study supports assertions that PIT-tag retention rates in small mammals are high, and suggests that rates of tag loss in small bat species are low when surgical adhesive is applied. Quantifying the rate of tag loss enables this variable to be incorporated into mark-recapture models. © 2021 The Wildlife Society.     

The use of PIT telemetry to study movements of ammocoetes and metamorphosing sea lampreys in river beds

Passive integrated transponder (PIT) tags were surgically implanted in 118 sea lamprey Petromyzon marinus ammocoetes which were left to recover in the laboratory for 2 months. During this period 55 individuals started to metamorphose. In the late summer of 2002 the tagged animals were released in a small tributary of the River Mondego, Portugal, and were regularly monitored for a period of 2 months using a portable PIT tag reader. The distribution of the released animals changed from an initial uniform pattern to a random distribution, and then to an aggregated pattern. At the end of the first week 60% of the tagged sea lampreys had already left the study area, indicating their dynamic behaviour. Ammocoetes were more active than metamorphosing sea lampreys, and downstream movements were more frequent when compared to the upstream ones, which were usually a short distance. In order to determine the influence of the dark‐light cycle in the diel activity rhythms, 10 tagged sea lamprey ammocoetes were released in a tank (2000 l capacity) and their position monitored twice a day, for a period of 1 month. Ammocoetes locomotor activity appeared to be conditioned by circadian rhythms, and they were particularly active during darkness.     

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

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.     

Long‐term effects of passive integrated transponder tagging (PIT tags) on the growth of the yellow European eel (Anguilla anguilla (Linnaeus, 1758))

Passive Integrated Transponder tags (PIT tags) are recommended as the most suitable method for tagging fish on the basis of their high retention and fish survival rates. The objective of this study was to determine the long‐term effects (between 1 and 11 years) of the PIT tag on the growth of the yellow European eel (Anguilla anguilla). A difference of more than 50% was observed in the growth of marked and unmarked yellow eels. If this is a general long‐term effect in all eels, it would seriously restrict the use of PIT tags for studying the dynamics of European eel populations, and so for their management.     

The behavioural response of the white-clawed crayfish (Austropotamobius pallipes) to five standard marking techniques over a 14-day period

ABSTRACT

The white-clawed crayfish (Austropotamobius pallipes), is classified as endangered in the 2010 IUCN Red List and is protected under Irish and European legislation due to a drastic decline in abundance and range over the past century. Mark-recapture methods play a vital role in the process of estimating population size, and in the monitoring and conservation of mobile species. A variety of marking techniques are routinely used in a range of crayfish species for ecological research. The majority of information on the effects of these marking techniques on the physiology of crayfish species focuses on survivability and growth, whereas information is scarce on the effects on crayfish behaviour. This study investigates the behavioural changes of crayfish in reaction to five commonly used marking techniques in laboratory conditions. The marking techniques used were internal and external passive integrated transponder (PIT) tags, visible implant elastomer (VIE) tags, cauterisation and ablation. Effects of marking technique on behaviour were evaluated immediately after marking, and over a 14-day period, on 78 crayfish. Results indicated that the internal passive integrated transponder (PIT) tags negatively affected crayfish behaviour by increasing resting levels. Ablation and cauterisation also increased grooming levels, while marking reduced activity levels in general. These effects on behaviour occurred immediately after marking, but quickly dissipated. These results suggest that the use of internal PIT tags for marking white-clawed crayfish may need to be avoided as increased resting levels could lead to increased exposure out of refuge and predation. This may have a detrimental impact on the welfare and conservation of white-clawed crayfish and also lead to biased population estimates during mark-recapture projects. The remaining marking techniques (external PIT tag, VIE tag, ablation, cauterisation) may be used, as changes in behaviour will not have a detrimental impact and therefore should not lead to biased population estimates.     

Long-term retention of internal elastomer tags in a wild population of painted crayfish (Panulirus versicolor [Latreille]) on the Great Barrier Reef

Many crustaceans are highly exploited fisheries species, but determining the population parameters of these animals via mark-recapture techniques is problematic, primarily due to tag-loss during moulting of the exoskeleton. Recently developed internal elastomer tags may overcome this challenging problem, since they are completely encased in the tissues beneath the exoskeleton. In this study, we evaluated the effectiveness of internal elastomer tags in a wild population of painted crayfish (Panulirus versicolor) over an 18-month period. Seventy animals were double-tagged in the abdominal musculature, with individuality obtained using different combinations of tag colour and tag location. Forty individuals were recaptured after 6, 12 and (or) 18 months, giving an overall recapture rate of 57%. Annual tag retention was estimated to be 98%, since only one instance of tag-loss was observed, despite numerous episodes of moulting among tagged individuals. The majority of tags (95%) were easily visible, even after 18 months at liberty. Nonetheless, small reductions in tag condition were observed after the first six months (mostly due to fading and [or] fragmentation), but this did not interfere with overall tag readability. Tag condition did not decline in the following 12 months, nor did it vary with gender or tag location. It is concluded that internal elastomer tags are an effective method for marking wild crayfish over long-term periods. Given the durability of elastomer, and the capacity for individual identification of large numbers of animals, such tags may be suitable for commercial-scale fishery applications.     

Improved methods for color‐marking hummingbirds

ABSTRACT Individual color‐marking is an essential tool for studying the behavior of free‐living birds. Hummingbirds represent a particular challenge for traditional avian color‐marking techniques because of their small size and short tarsi. Although several techniques have been successfully used, the retention time of color‐markers and their safety and ease of construction could be improved. I developed two new color‐marking techniques for marking Little Hermits (Phaethornis longuemareus): (1) a plastic back tag constructed by fusing colored beads, and (2) a leg tag attached to a metal band fitted around the tarsus. Both tag designs were visible in field conditions, and neither appeared to adversely affect behavior. Both back and leg tags had high retention rates within seasons, but back tags had a poor retention rate between years. Although these marking techniques were designed for use on one species of hummingbird, they would likely also be useful with other species of hummingbirds.     

A passive integrated transponder tag implanted by a new alternative surgical method: effects on the oriental weather loach (Misgurnus anguillicaudatus) and application in a small irrigation system

We validated the effects of a passive integrated transponder (PIT) tagging process on the oriental weather loach Misgurnus anguillicaudatus. Laboratory experiments were conducted to assess the effects of PIT tagging on fish survival, growth, wound healing, and tag omission. Two tagging protocols, standard syringe injection versus insertion through a small hole pierced by a fine needle-shaped awl, were compared using a 12.5 × 2.07 mm² tag. A control group was also included. In comparison with the awl technique, syringe injection heightened the mortality of the loach and delayed healing of the wound caused by tag insertion. No effects of either PIT tagging method were detected on the growth of surviving loach. We also field-tested similarly tagged populations within a river-based irrigation system of Sado Island, Japan. Two different sized tags (long, 12.5 × 2.07 mm²; short, 8.5 × 2.12 mm²) were compared by using antenna loggers which detected fish movement through gates and automatically logged tagged fish’s tag IDs and timestamps. By comparing logged data and actual fish collection surveys both below and above the gates, 77% and 30% of actual loach movements were confirmed to have been successfully logged for the long and short tags, respectively. The awl insertion technique with the longer tag is therefore recommended for use in similar studies of smaller fish species.     

Patterns of migration and residency in coastal cutthroat trout Oncorhynchus clarkii clarkii from two tributaries of the lower Columbia River

Coastal cutthroat trout Onchorhynchus clarkii clarkii life-history variants, migration and freshwater residency were monitored using stationary passive integrated transponder (PIT) tag arrays in two tributaries of the Columbia River from 2001 to 2005 (Abernathy Creek, river kilometre, rkm 76) and from 2002 to 2005 (Chinook River, rkm 6). In 2001–2003 and 2002–2003 (Abernathy and Chinook, respectively), 300–500 coastal O. c. clarkii were captured in each tributary by electrofishing and implanted with 23 mm PIT tags. PIT arrays monitored movements from the initiation of tagging through the spring of 2005. Rotary screw traps were also operated on both tributaries. In Abernathy Creek, 28% of tagged individuals were observed through either active capture or passive interrogation. Of these, 32% were identified as migrants and 68% were identified as residents. In the Chinook River, 48% of tagged fish were observed subsequent to tagging; 92% of these fish were migrants and only 8% were resident. In both tributaries, a greater proportion of resident fish were in the upper reaches. The majority of migrants (78–93%) moved the spring following tagging. Migrants leaving at age 2+ years tended to grow faster than those that migrated at age 3+ years or residents. Patterns of growth or growth opportunities may influence both patterns of life-history expression and the timing of migration.     

Evaluation of marking and tagging methods for genetic studies in carp

A variety of marking and tagging methods were tested on common carp (Cyprinus carpio L.) with the aim of identifying suitable methods for genetic studies in this and other species of carp. Elastomer and Alcian blue dye marking; Cold and Silver nitrate branding; Floy, Fingerling, Carlin disc and visible implant tags; and fin clipping were all tested on a range of sizes of common carp (from mean weights of 10–25 g up to 600–800 g). The branding and tagging methods tested did not give satisfactory retention rates. A combination of elastomer marking and fin clipping was then tested as a method for strain identification in a growth comparison trial on catla (Catla catla Hamilton) and found to be satisfactory for this purpose. Passive integrated transponders (PIT) tags were used to individually identify catla of wild or hatchery origin being grown for use as broodstock. These had almost 100% (98.8%) retention rates, but are expensive compared to most other tagging methods.     

Efficacy of tagging European catfish Silurus glanis (L., 1758) released into ponds

The efficacy and sub‐lethal consequences of single and double tagging European catfish Silurus glanis with Petersen disc and passive integrated transponder (PIT) tags were examined in short (laboratory) and longer‐term (field) experiments. Tag retention in the laboratory was 100%, with normal behaviour (i.e. feeding) in all fish returning within 36 h. In the field, 65 of 120 tagged S. glanis were recaptured from five small study ponds, with 85% retaining their PIT tags, though recapture rates and tagging efficacy were highly variable amongst locations. This is consistent with literature for other fishes, suggesting that tagging efficiency is variable across species and largely context dependent (fish length, tagging location, habitat).