Visible Implant Elastomer Research Articles

Evaluation of individual visual implant elastomer tag marking of Japanese eel (Anguilla japonica) larvae

Visual implant elastomer (VIE) marking was evaluated as a tool for individual tagging of larval Japanese eels, Anguilla japonica, during rearing conditions. Combinations of eight colors of VIE tag were used to individually mark leptocephalus larvae (104–110 days post hatched) by injecting them with either a mixture of a silicone color material and a curing agent, or only color material. Injections were at three locations on the dorso-lateral body surface for individual identification, and a sham-operated control group was also prepared. Tag retention was 100% with or without curing agent, and individuals could be tracked until larvae completely metamorphosed into glass eels. After some initial mortality, the survival and growth rates were not different between each treatment group. These results suggested that VIE tagging could provide good individual larva identification method for research during rearing conditions.

Standard methods for marking caudate amphibians do not impair animal welfare over the short term: An experimental approach.

Major advancements in ecology and biodiversity conservation have been made thanks to methods for marking and individually tracking animals. Marking animals is both widely used and controversial due to the potential consequences for animal welfare, which are often incompletely evaluated prior to implementation. Two outstanding knowledge gaps concerning the welfare consequences of individual marking are their short-term behavioural impacts and the relative impacts from marking versus the handling of animals while carrying out procedures. We addressed these knowledge gaps through an experimental study of alpine newts (Ichthyosaura alpestris) in which we varied handling and marking procedures. Examining individual responses to handling, toe clipping and visible implant elastomer (VIE) injection over 21 days showed that handling and marking elicited increased newt activity and hesitancy to feed compared to animals that did not get handled or marked. These effects were apparent even when animals were handled only (not marked), and marking did not further increase the magnitude of responses. Increases in newt activity and feeding hesitancy were transient; they were not observed in the weeks following handling and marking. While previous studies emphasise the welfare impacts of marking procedures themselves, these findings highlight that handling alone can elicit behavioural changes with possible costs to welfare. Yet, the transient nature of behavioural responses suggests that immediate costs of handling may be subsequently compensated for in the short term.

Zebrafish Injectable Plastic for Identification Tagging (ZIP IT) for larvae to adults using a fluorescent Visible Implant Elastomer

Distinguishing individuals or small groups is essential for many experiments. The regenerative properties of zebrafish make traditional marking methods for rodent models (e.g., tattoos, tissue clipping) ineffective. Fluorescent Visible Implant Elastomer (VIE) can permanently mark juvenile and adult zebrafish but to date no marking technique has been described for larval stage zebrafish. This protocol, Zebrafish Injectable Plastic for Identification Tagging (ZIP IT), utilizes VIE in zebrafish as early as 2 days post fertilization (dpf) using standard microinjection methods and direct injection using an insulin syringe at one month. Larval zebrafish between 2 and 7 dpf were injected in the dorsal musculature. At one month, retention and visibility of the VIE was observed in 72% of the injected fish with no effect on growth; however, a variable change in mortality was observed, generally higher than the uninjected fish. This demonstrates that VIE can be used in very early stages of fish development, providing the first procedure to track individuals or groups within a larger population. Subcutaneous injection of juvenile zebrafish starting at one month has greater than 99%-mark retention and visibility with very low mortality. The combination of larvae and juvenile VIE injections also provide a powerful tool to track and gather data from marked fish throughout their lifespan.•We present a method for tagging individuals or groups of zebrafish at most life stages (larvae or juvenile/adult) with Visible Implant Elastomer (VIE).•The larvae and juvenile injection procedures can be combined so that an individual fish can be tagged for its entire lifetime. Larvae injections become significantly less visible after one month; however, the fish can be reinjected using the juvenile procedure, thus allowing continuity of the visible mark.•This protocol was empirically built on the “Evaluation of VIE tags in Zebrafish (Danio rerio)” by Hohn and Petrie-Hanson (2013) and expanded to include larvae and a small batch elastomer mixing technique.

Estuarine-Specific Migration of Glass Eels in the Ems Estuary

Understanding recruitment of glass eels in estuaries is crucial for the conservation of the European eel (Anguilla anguilla). However, basic knowledge on estuarine-specific glass eel migration, including in estuarine harbours, is mostly lacking. Therefore, we studied glass eel migration in the Dutch–German Ems estuary and the harbour at Delfzijl (The Netherlands) and tagged glass eels with Visual Implant Elastomer tags (VIE tags). We released 2000 tagged glass eels into the Ems estuary itself and 1000 tagged glass eels into the tidal harbour at Delfzijl. At three estuarine locations, i.e., Delfzijl–Duurswold, Termunterzijl, and Nieuwe Statenzijl, glass eel collectors were strategically placed, each location being progressively situated further upstream in the Ems estuary. Most glass eels (nuntagged = 97,089, ntagged = 74) were caught at Nieuwe Statenzijl, although this location is much further upstream. Lower numbers of glass eels (nuntagged = 1856, n tagged = 31) were caught at Delfzijl–Duurswold and Termunterzijl (nuntagged = 1192, ntagged = 7). Glass eels arrived approximately a week earlier at Nieuwe Statenzijl than at the other two locations, and the migration speed of tagged glass eels was highest at Nieuwe Statenzijl (>2 km/day) and lower (<1 km/day) at Delfzijl–Duurswold. Our study highlights that migration and the resulting potential recruitment of glass eels in estuaries and harbours may vary considerably both spatially and temporally. Further research on estuarine-specific factors that influence glass eel migration, such as the (anthropogenically altered) tidal action and flow, will provide valuable information on what influences glass eel migration in estuaries.

Conditioning to predators improves survival of stocked Murray cod (Maccullochella peelii) fingerlings

Context Following recent major fish kill events, there is increasing interest in stocking Murray cod fingerlings to help fish stocks recover. Strategies that can increase post-release survival of stocked fingerlings are important for conservation stocking of Murray cod and may also have application to other species. Aims The aim of this work was to evaluate whether pre-release predator recognition and avoidance training conferred a survival advantage on stocked Murray cod (Maccullochella peelii) fingerlings. Predator-free release enclosures were also evaluated as a method to improve survival. Methods Fingerlings were trained by exposure to predators and skin extract. Fingerlings were marked with visual implant elastomer (VIE) tags to denote training status and release strategy (trained, untrained, soft release, standard release). Fingerlings were released at three sites in the northern Murray–Darling Basin. Marked fish were recaptured by electrofishing 24 h post-release and quarterly up to 15 months post-release. Key results Trained Murray cod had higher relative survival than did untrained fish. The mean recapture rate of trained fish was twice that of untrained fish. Fingerlings released directly into the waterbody had significantly higher recapture rates than did fingerlings acclimated for 90 min in predator-free enclosures. Conclusions Predator conditioning training provides a survival advantage to stocked Murray cod fingerlings. However, predator-free release enclosures conferred a disadvantage. Implications Pre-release training of Murray cod fingerlings could be beneficial to conservation and recreational-fish stocking programs. We recommend stocking trained cod fingerlings directly into the receiving environment, rather than into soft-release enclosures, so as to maximise their chance of survival.

Species composition, abundance, size distribution, sex ratios, and movement of Scylla mud crabs within the mangrove ecosystem at Setiu Wetland, Terengganu, Malaysia

The aim of the present study was to determine the movement patterns of mud crabs, genus Scylla, within the mangrove area of the Setiu Wetland in Terengganu, Malaysia. Mark-release-recapture technique were conducted during 24 sampling trips. A fluorescent visible implant elastomer (VIE) tag was inserted within the crab’s shell and they were released at the same capture stations over an interval of two weeks before the next sampling. A total of 288 crabs of various sizes, sex and species were identified, measured, tagged and recorded. The numbers of male crabs were higher than females. Three species were present, dominated by S. olivacea at 54.2% and S.tranquebarica at 26.4%, with S. paramamosain in third place at 19.4%. Among the 288 crabs that were tagged and released, 26.38% were recaptured. The tagged crabs did not move very far from the release station based on the recapture data. The greatest mean chance of being recaptured within 24 h was 44.5%, and there were no tagged crabs recaptured after 48 h even on sampling trips at several points from the release site. Knowledge of movement patterns is essential to understand migration and population dynamics and the relationship between reproduction and local distribution.

Evaluation of visible implants elastomer tags in juveniles of red octopus Octopus maya

In this work, the effects of visible implant elastomer (VIE) tags on survival and body growth rate on juvenile red octopus Octopus maya from the Yucatan Peninsula were tested under controlled conditions. Juveniles with an average weight of 1.14 g were not affected by VIE within 30 days, so this methodology is suggested as a useful tool to study the life cycle aspects of this important fishery species.

Evaluation of Tagging Methods for Unique Identification of Individuals in Three Aquatic Eurycea Salamander Species

Marking or tagging salamanders increases efficiencies in the operations and management of captive populations and facilitates techniques for monitoring demographics of wild populations. Tags facilitate monitoring of longitudinal data for individual animals such as age or estimated age, growth, reproduction, and health. We evaluated three different tagging methods on Texas Blind, San Marcos, and Comal Springs Salamanders to determine success of each as a long-term marker of individual animals. For this study, we selected visible implant elastomer (VIE), visible implant alphanumeric tags (VIA), and passive integrated transponders (PIT). Of these, only VIE tagging has been evaluated in San Marcos Salamanders; none have been evaluated for use in the other two salamander species studied; and comparison studies among these tags for fully aquatic salamander species have not been performed. These tag types were selected for their effectiveness with other salamander species, ability to be quickly and easily identified tank-side, minimal negative effects on organisms, and perceived ease of implanting the tags. The VIE tags were retained by all species and had high readability scores. However, the issues of tag breakage and deterioration should be considered when using VIE tags. VIA tags were rejected in all but one San Marcos Salamander and all Comal Springs Salamanders, but 90% of Texas Blind Salamanders retained them. PIT tags were not tested on San Marcos, Comal Springs, and smaller Texas Blind Salamanders due to size of tag and low retention rate in larger salamanders. Of the tags evaluated in this study, VIE was the most effective in terms of retention, readability, and ease of insertion.

Standardized microsatellite panels for pedigree management of farmed white-leg shrimp (Penaeus vannamei) stocks validated in a VIE tagged family selection line

Establishing an effective and reliable system for tracking family pedigree is critical for the success of genetic improvement programs in aquaculture. Parentage assignment using molecular markers can provide an accurate and affordable pedigree management tool for selective breeding projects to maximize genetic gains while minimizing inbreeding levels. In this study, we evaluated 30 microsatellite loci for white-leg shrimp reported in earlier publications and selected 12 markers to develop two standardized multiplex microsatellite panels (SMpv01 and SMpv02) for pedigree management. Mean expected heterozygosity and polymorphic information content across the 12 loci included in the two panels were 0.725 and 0.704 respectively, indicating that the two multiplex panels would be highly informative for parentage assignment analysis. Simulation assignment runs of 10, 000 offspring, originating from 100 candidate dams resulted in complete maternity assignment with more than 11 loci at the 95% confidence level (CI). Capacity of the two marker panels for maternity assignment were tested using CERVUS and COLONY in a family selection line with full sibling relationships inferred from VIE tags. Among 369 individuals from 37 maternal families, CERVUS achieved 100% assignment while 69 assignments could not be matched with pedigree inferred from VIE tags. Overall assignment rate with COLONY was 94.3%, with 29 assignments not consistent with pedigree information from visible implant elastomer (VIE) tags. We also assessed the utility of VIE tags for a combination of nine tag colours and three tagging positions to track family ID via cross validation with molecular assignment. No statistical difference was found for random effects of tag position or VIE tag colour. This indicates that the VIE tag approach tested here would be a highly effective tool for pedigree management of cultured Penaeus vannamei stocks. In summary, our results provide two standardized multiplex microsatellite panels to support pedigree management of farmed white-leg shrimp in a selective breeding program.

Migration and Histologic Effects of Visible Implant Elastomer (VIE) and Passive Integrated Transponder (PIT) Tags in the Marine Toad (Rhinella marina).

Simple SummaryPassive integrated transponder (PIT) and visible implant elastomer (VIE) tags are commonly used to identify reptiles, amphibians, and fish. The aim of this study was to evaluate for pathologic changes associated with these tags in the marine toad (Rhinella marina). For the 56 toads in this study, all PIT tags were functional and 95% remained at the insertion site with little to no damage to the tissue. However, only 48% of VIE tags were functional, i.e., visible through the skin. Although there was little to no damage to the skin at the site of placement, the VIE was found to have migrated to the kidneys in 98% of toads as well as along the legs and sporadically in other internal organs. VIE in the kidney caused inflammation and damage to the vasculature that progressed in severity over time. Based on these findings, the authors recommend the use of PIT tags over VIE tags for identification of adult anurans, when feasible.Passive integrated transponder (PIT) and visible implant elastomer (VIE) tags are commonly used to identify reptiles, amphibians, and fish. Despite reports of good retention rates and little to no negative effect on survival time, migration remains a concern and histologic changes have not been widely evaluated. Fifty-six wild-caught marine toads (Rhinella marina) were marked with a PIT tag in the left caudal thigh and a VIE tag over the right gastrocnemius muscle prior to transport to the North Carolina Zoo. Fourteen toads were then humanely euthanized on day 9, 15, 32, and 62 for postmortem examination and histopathology which were compared to 10 control toads with no tags. All PIT tags were functional and 95% remained at the insertion site with minimal to no histologic changes. Externally, 48% of VIE tags were visible through the skin at the original site of injection under fluorescent or UV light. Upon gross examination of the tissues, VIE tags had an overall retention rate of 62% at the injection site, with similar retention rates across time points. Migrated VIE material was visible grossly and histologically in the kidneys of 98% of toads and along the right leg, proximally and distally, in 25% of toads. VIE material was also found sporadically in mesentery, colon, and free in the coelomic cavity. Histologically, VIE material in the skin was surrounded by minimal to mild granulomatous inflammation while in the kidney it was associated with dilation of the small vessels, edema, and granulomatous nephritis that progressed in severity over time. Based on these findings, the authors recommend the use of PIT tags over VIE tags for identification of adult anurans, when feasible.

Marking through molts: An evaluation of visible implant elastomer to permanently mark individuals in a lower termite species.

Advances in individual marking methods have facilitated detailed studies of animal populations and behavior as they allow tracking of individuals through time and space. Hemimetabolous insects, representing a wide range of commonly used model organisms, present a unique challenge to individual marking as they are not only generally small‐bodied, but also molt throughout development, meaning that traditional surface marks are not persistent.Visible implant elastomer (VIE) offers a potential solution as small amounts of the inert polymer can be implanted under the skin or cuticle of an animal. VIE has proved useful for individually marking fish, crustaceans, and amphibians in both field and laboratory studies and has recently been successfully trialed in laboratory populations of worms and fly larvae. We trialed VIE in the single‐piece nesting termite Zootermopsis angusticollis, a small hemimetabolous insect.We found that there was no effect of VIE on survival and that marks persisted following molting. However, we found some evidence that marked termites performed less allogrooming and trophallaxis than controls, although effect sizes were very small.Our study suggests that VIE is an effective technique for marking small hemimetabolous insects like termites but we advocate that caution is applied, particularly when behavioral observation is important.

Retention of Postocular Visible Implant Elastomer in Two Sizes of Adult Brown Trout and Rainbow Trout

AbstractRetention of visible implant elastomer (VIE) was assessed during an evaluation of put‐grow‐and‐take Brown Trout Salmo trutta and Rainbow Trout Oncorhynchus mykiss stockings in Apalachia Reservoir, North Carolina. Visible implant elastomer was injected in the postocular adipose tissue of two sizes (approximately 254 [small] and 356 [large] mm TL) of Brown Trout and Rainbow Trout in November 2012–2015. Each year, 1,000 large and 1,500 small trout of each species were marked with VIE. Mark retention was assessed after 30 d in a hatchery and during poststocking collection events in Apalachia Reservoir. The recaptured trout were examined for VIE marks during annual spring electrofishing, fall gill‐net samples, and a year‐long creel survey. The 30‐d VIE retention rate for all trout and all years was 99.9%. Following stocking, both sizes of Rainbow Trout were collected up to 17 months after marking and VIE retention was 100%. Large and small Brown Trout were collected up to 33 and 34 months after marking, and the VIE retention rates were 100% and 99.3%, respectively. This study found visible implant elastomer to be an effective and simple batch mark that remained visible on Rainbow Trout for up to 17 months and Brown Trout for up to 34 months postmarking in the wild.

Evaluation of Visual Implant Elastomer, PIT, and p‐Chip Tagging Methods in a Small‐Bodied Minnow Species

AbstractReliable fish tagging methods are needed to conduct studies (e.g., movement, habitat, abundance) that inform conservation and management decisions; however, dependable tagging approaches are lacking for many small‐bodied fishes. Therefore, our study objective was to determine survival, tag retention (visible implant elastomer [VIE], PIT, or light‐activated microtransponder [“p‐Chip”]) and tagging effects on short‐term growth of the federally threatened Arkansas River Shiner Notropis girardi. We also examined the use of anesthesia to reduce fish mortality (i.e., reduce handling time) and improve tagging efficiency. Fish tagged with p‐Chips had the highest survival (87%), whereas VIE‐tagged fish had the second highest survival (67%). Visible implant elastomer tags were retained in our fish 88% of the time, and retention was also high using p‐Chips (72%). Location of the VIE tag did not significantly affect survival or retention rates. Survival of PIT‐tagged fish significantly increased from 53% to 83% when handling time was reduced; however, tag retention was relatively low in both cases (50% and 45%, respectively). The majority of tagged fish across experiments (83–100%) gained weight regardless of tag type. If the research or management goal is to tag Arkansas River Shiner or similar species with individual identification, p‐Chips appear to be an appropriate tag. Particularly if cost is limiting or higher tag retention is needed, VIE tags would also be appropriate for batch tagging (i.e., no individual identification). Additional studies to broaden application of tagging to other small‐bodied species would be beneficial.

Identification of Individual Zebrafish (Danio rerio): A Refined Protocol for VIE Tagging Whilst Considering Animal Welfare and the Principles of the 3Rs.

Simple SummaryIn aquatic ecology research studies commonly employ a tagging technique named visible implant elastomer (VIE). Despite existing widespread guidance on the use of this marking technique on fish, there is still a lack of information regarding efficiency in small fishes, as well as its impact on fish welfare. The current paper highlights important animal welfare issues and introduces a newly improved VIE tagging protocol, presenting information on individual survival rate, tag retention, and use of different elastomer colours, quantified in different populations and age groups of zebrafish. Specifically, we compare a previously used tagging method with a newly improved protocol which places particular emphasis to the Three Rs, helping to refine this scientific procedure. The shared detailed protocol and information will be beneficial to the zebrafish research community and beyond.In aquatic ecology, studies have commonly employed a tagging technique known as visible implant elastomer (VIE). This method has not been widely adopted by the zebrafish research community and also lacks refinement with regard to animal welfare. The current paper introduces a new VIE tagging protocol, with the aim of improving existing tagging techniques by placing particular emphasis on the Three Rs. To improve animal welfare and fish survival, we added the use of an analgesic compound (lidocaine) through the marking procedure, followed by after-treatment with antiseptics (melaleuca, aloe vera, and PVP-I as active ingredients) to improve tissue regeneration and healing. The newly improved protocol has been quantitatively evaluated on different populations and age groups of zebrafish. This study will be useful to the scientific zebrafish community and to the wider field including biologist and aquarists, especially in consideration of animal welfare, where tagging techniques are considered as a potential noxious stimulus for fish.

Estimating population density of the medicinal leech Hirudo orientalis Utevsky and Trontelj, 2005 (Clitellata: Hirudinida) using Visible Implant Elastomer tags

ABSTRACT Medicinal leeches have lately come into the spotlight as useful and effective invertebrates in the treatment of some diseases and surgical procedures. Populations of the Iranian medicinal leech, Hirudo orientalis, are under considerable threat due to over-exploitation. To find a viable technique for estimating leech population size in their natural habitat, a tagging method using fluorescent dye was investigated. In the present study, to test the method’s efficiency, numbers of medicinal leeches were estimated in the artificial leech ponds of the University of Tehran, by the capture–mark–recapture method, using the Lincoln index. Leeches were caught from the ponds, marked using commercially available visible implant elastomer (VIE) tags, released and later recaptured. The technique proved successful, and low standard error values (7.07–11.85) in this study showed that the VIE tagging method could be applied as a useful tool for evaluating medicinal leech population size. This is the first use of this method to estimate medicinal leech population size.

Evaluation of Visible Implant Elastomer Tags in Wild Coastal Cutthroat Trout in the Marine Environment

AbstractWe evaluated the detectability of visible implant elastomer (VIE) tags in Coastal Cutthroat Trout Oncorynchus clarkii clarkii in the marine environment by comparing visually identified recaptures from VIE tags with known recaptures that were identified through genotype matching. A total of 89 individual Coastal Cutthroat Trout were marked in the lower jaw with colored VIE tags, sampled for genetics, and recaptured across 12 months in 2015. The rate of correspondence between the VIE tags and genetic matches was 92% (82/89) of the recaptured Coastal Cutthroat Trout in the nearshore marine environment. We found that red‐ and blue‐colored VIE tags were detected at a higher rate (100%) than were yellow‐ and orange‐colored tags (87.3% and 90.6%, respectively). In contrast, tag type (single or double), tag location (left or right), fish length (FL, mm), and time (days) since tagging had no effect on tag detectability during the study period. All of the tag colors were recovered for the maximum life of the study (up to 342 days). In all of the cases of nondetections (5/89), the tags were not identified upon initial recapture or subsequent capture events, suggesting that they were lost or not visible immediately upon insertion in the field—as opposed to being unidentified due to the degradation of tag detectability over time. The results of this study suggest that VIE tags have the potential to be detectable in juvenile and adult Coastal Cutthroat Trout for at least 12 months after insertion, with blue and red performing the best. Additional monitoring extending beyond 12 months after tagging would be necessary to identify the maximum life of VIE tags.

Visible implant elastomer (VIE) success in early larval stages of a tropical amphibian species.

Animals are often difficult to distinguish at an individual level, and being able to identify individuals can be crucial in ecological or behavioral studies. In response to this challenge, biologists have developed a range of marking (tattoos, brands, toe-clips) and tagging (banding, collars, PIT, VIA, VIE) methods to identify individuals and cohorts. Animals with complex life cycles are notoriously hard to mark because of the distortion or loss of the tag across metamorphosis. In amphibians, few studies have attempted larval tagging and none have been conducted on a tropical species. Here, we present the first successful account of VIE tagging in early larval stages (Gosner stage 25) of the dyeing poison frog (Dendrobates tinctorius) coupled with a novel anesthetic (2-PHE) application for tadpoles that does not require buffering. Mean weight of individuals at time of tagging was 0.12 g, which is the smallest and developmentally youngest anuran larvae tagged to date. We report 81% tag detection over the first month of development, as well as the persistence of tags across metamorphosis in this species. Cumulative tag retention vs tag observation differed by approximately 15% across larval development demonstrating that “lost” tags can be found later in development. Tagging had no effect on tadpole growth rate or survival. Successful application of VIE tags on D. tinctorius tadpoles introduces a new method that can be applied to better understand early life development and dispersal in various tropical species.

Marking the un-markable: visible implant elastomer in wild juvenile snakes

Marking individuals is a key component of many ecological studies, but with some animals, such as juvenile snakes, it has proven problematic because of size constraints. This impedes our understanding of their habits in the wild. We marked juvenile Aesculapian snakes (Zamenis longissimus) in North Wales with visible implant elastomer (VIE), and recaptured them the following season. Our results demonstrate that the use of VIE is an effective marking method for small snakes, negating the need for tissue removal when marking. We suggest it represents a promising development in the ecological study of snakes, and is especially useful in species that undergo ontogenetic pattern changes.

Annual changes in corticosterone and its response to handling, tagging and short-term captivity in Nyctibatrachus humayuni

Glucocorticoids (GCs) are primarily involved in mobilising energy reserves to various physiological processes including reproduction. During situations of stress, GCs also help in coping with stress by diverting energy away from processes such as growth and reproduction. Hence, studying annual and seasonal changes in GCs of wild populations can help in understanding their role in stress management and reproduction. The quantification of GCs in wild animals involves capturing, handling and restraining, which could be stressful. Moreover, different species may exhibit differential sensitivity to different stressors. Hence, determining species-specific sensitivities and responses to different stressors may help in developing effective conservation measures. In this context, we studied the annual and seasonal variations in corticosterone metabolites of the Bombay night frog, Nyctibatrachus humayuni. In addition, the effects of handling, marking and short-term captivity (24 h) on corticosterone metabolite levels of N. humayuni were determined. Our results show that urinary corticosterone metabolites (UCM) varied significantly annually and between the sexes; in males, the levels were highest during the breeding season, whilst in females, the levels were highest just before the breeding season. Interestingly, UCM levels of both the sexes were not affected by tagging with visual implant elastomer (VIE), and by short-term captivity, suggesting that these manipulations were not stressful in terms of corticosterone responses.

Use of visible implant elastomer and its effect on the survival of an endangered minute salamander

The population study of threatened species requires marking techniques that do not affect the survival of individuals. In this study, we evaluated the effectiveness of visible implant elastomer (VIE) in the identification and survival of individuals of the salamander Parvimolge townsendi. We compared three salamander groups under different treatments: intervened, simulated intervention and control. No significant mortality differences were observed between groups (with two, none, and one individual, respectively), but implant migration was observe in four of 10 intervened individuals. Although VIE does not have a significant effect on survival, implant migration should be considered before use in population studies.