Portable Passive Integrated Transponder Research Articles

Mapping the Relative Probability of Common Toad Occurrence in Terrestrial Lowland Farm Habitat in the United Kingdom.

IntroductionThe common toad (Bufo bufo) is of increasing conservation concern in the United Kingdom (UK) due to dramatic population declines occurring in the past century. Many of these population declines coincided with reductions in both terrestrial and aquatic habitat availability and quality and have been primarily attributed to the effect of agricultural land conversion (of natural and semi-natural habitats to arable and pasture fields) and pond drainage. However, there is little evidence available to link habitat availability with common toad population declines, especially when examined at a broad landscape scale. Assessing such patterns of population declines at the landscape scale, for instance, require an understanding of how this species uses terrestrial habitat.MethodsWe intensively studied the terrestrial resource selection of a large population of common toads in Oxfordshire, England, UK. Adult common toads were fitted with passive integrated transponder (PIT) tags to allow detection in the terrestrial environment using a portable PIT antenna once toads left the pond and before going into hibernation (April/May-October 2012 and 2013). We developed a population-level resource selection function (RSF) to assess the relative probability of toad occurrence in the terrestrial environment by collecting location data for 90 recaptured toads.ResultsThe predicted relative probability of toad occurrence for this population was greatest in wooded habitat near to water bodies; relative probability of occurrence declined dramatically > 50 m from these habitats. Toads also tended to select habitat near to their breeding pond and toad occurrence was negatively related to urban environments.

Feasibility of Passive Integrated Transponder Technology to Study In Situ Movements of Larval Sea Lamprey

Abstract In the Laurentian Great Lakes, sea lamprey Petromyzon marinus is an invasive species controlled primarily through application of selective toxicants (lampricides) to tributaries expected to contain the most large larvae (>100 mm). Current assessment techniques make the assumption that larvae occupy all stream habitats in the same proportion irrespective of size or life history stage. Testing this assumption relies on the availability of a marking method to determine individual animal movement between habitats over time. To evaluate the feasibility of using passive integrated transponder (PIT) technology to detect sea lamprey larvae in situ, we implanted two sizes of PIT tags (8 and 9 mm) in larvae of less than 120-mm average length to assess survival, tag loss, behavior, and detectability in situ. Larval mortality and tag loss were lower when smaller tags were used, but mortalities were still high (60%) due to the small body cavity severely restricting internal tag implantation. Burrowing performance of 8-mm PIT-tagged larvae and untagged larvae was compared, and tagged larvae spent significantly more time moving (35 vs. 21 s) and more total time (71 vs. 31 s) to completely burrow into the substrate than untagged larvae. Detectability of those 8- and 9-mm PIT-tagged larvae in situ was evaluated by releasing them in a simulated stream and using a portable PIT tag antenna on three occasions to relocate them at a detection rate that ranged from 47 to 100%. Feasibility of tracking individual larval sea lamprey movements was evaluated by tagging larvae with either 9-mm PIT tags, visible implant alpha tags, or visible implant elastomer tags; releasing them in a natural stream; and relocating them by PIT antenna or recapturing them by electrofishing. In the natural stream, a total of 36% of 9-mm PIT-tagged larvae were relocated in situ during the study period, whereas less than 7% of larvae tagged with other tag types were recaptured. The smallest currently available PIT tags are not suitable for tracking movements of individual sea lamprey larvae less than 120 mm in average length because of the significant effects of tagging on behavior and survival rates. We are unaware of other tagging technologies currently available to track individual sea lamprey larvae of this size range in situ over time.

Habitat use of redfin bullies (Gobiomorphus huttoni) in a small upland stream in Manawatu, New Zealand

This study uses Passive Integrated Transponder (PIT) technology to describe the habitat use patterns of the small, benthic redfin bully (Gobiomorphus huttoni). A 100-m reach of small upland stream in Manawatu, New Zealand was mapped to scale and inventoried for microhabitat variables. Flow velocity, depth, surface turbulence, substrate size and interstitial refuge space availability were measured in 0.25-m2 quadrats throughout the reach. A total of 67 redfin bullies were PIT tagged within the reach and monitored during day and night surveys in 2008 with a portable PIT monitoring system. Of these, 72 % were detected at least once and 64 % were detected 5 times or more within the study reach. Univariate analyses showed that redfin bullies utilized microhabitats that had larger substrate particles and more interstitial refuge spaces compared with all microhabitats available in the reach. During the day, redfin bullies were found in areas with larger substrates than areas where they were found at night. No differences in microhabitat use were found regarding gender, body size or season. Multivariate analysis revealed four macrohabitat types and showed that redfin bullies used deeper, complex macrohabitats during the day, then spread out to occupy all available macrohabitats at night. These findings have implications for river managers trying to cope with increasing anthropogenic impacts such as sedimentation.

Successful use of a passive integrated transponder (PIT) system for below-ground detection of plethodontid salamanders

Context Passive integrated transponder (PIT) technology allows for permanent and unambiguous marking of animals and has recently been adapted for locating tagged individuals in the field with portable detection systems. Aims We seek to assess the effects of PIT tagging on the growth and survival of plethodontid salamanders in the laboratory and to evaluate the effectiveness of this method for subterranean detection of salamanders in the field. Methods In a laboratory experiment, we assigned 36 Plethodon shermani to either a PIT tag or control group and compared survival and growth rates over the course of 9 weeks. For the field study, we implanted six Plethodon metcalfi with PIT tags and conducted surveys so as to determine their below-ground positions with a portable detector. Key results We found no effect of PIT tagging on either growth or survival in the laboratory. In the field, PIT telemetry resulted in an overall detection efficiency of 44%, with nighttime surveys yielding a greater detection efficiency than daytime surveys. This technique provided a significant improvement over traditional hand-capture because detected salamanders were rarely visible on the ground surface. Key conclusions Our study indicates that even these relatively small-bodied salamanders (range: 2.14–5.18 g) are capable of bearing PIT tag implants and confirms the results of previous studies that found no effect of PIT tagging on the health or survival of amphibians. This study further demonstrates that the use of a portable PIT detector can be an effective method for locating below-ground salamanders. Implications Because of the small size and long lifespan of PIT tags, we believe portable PIT detectors can provide researchers with an unprecedented level of detail for studies of the movement behaviour, spatial ecology and management of species that are small or otherwise challenging to detect and monitor with other techniques.

Monitoring a New Zealand freshwater fish community using passive integrated transponder (PIT) technology; lessons learned and recommendations for future use

One hundred and thirty individual fish were collected and passive integrated transponder (PIT) tagged in a 100-m reach of a small North Island, New Zealand stream. The positions of the fish were monitored with a hand-held portable PIT antenna over 41 occasions during day and night in 2008/2009. Redfin bully (Gobiomorphus huttoni), shortjaw kokopu (Galaxias postvectis) and koaro (Galaxias brevipinnis) were the most represented and commonly detected species (75%, 73% and 83% detection rates, respectively). Nine longfin eels (Anguilla dieffenbachii) were tagged but only two were later detected. Redfin bullies with lower condition factors than conspecifics were less likely to be detected following tag implantation. Shortjaw kokopu were less likely to be detected but more retained tags than redfins and koaro. No difference in tag detection rates was found over a range of flow levels, nor between surveying during day and night, although a small decline in detection rates occurred as water temperature decreased and with time since sampling. The PIT technique proved to have significant potential for monitoring New Zealand native stream fish communities and has many advantages over previously used techniques, particularly in relation to the collection of fine-scale spatial data on multiple species.

Determining the effects of species, environmental conditions and tracking method on the detection efficiency of portable PIT telemetry

The efficiency of portable passive integrated transponder (PIT) telemetry at detecting five fish species in a small river was evaluated under different environmental and tracking conditions. Significant differences between species were apparent, with detection efficiency varying between 0·7% (Leuciscus leuciscus) and 43·1% (Salmo trutta). Conditions of reduced flow and tracking in a downstream direction significantly increased detection efficiency for salmonids, while time of day had no significant effect for any species.

Portable PIT detector as a new tool for non-disruptively locating individually tagged amphibians in the field: a case study with Pyrenean brook salamanders (Calotriton asper)

Passive Integrated Transponder (PIT) telemetry has recently been adapted for locating PIT-tagged fish in shallow waters using portable detectors. In the present study, we tested this method for adult amphibians (Pyrenean brook salamanders, Calotriton asper) PIT-tagged with 12-mm transponders in a headwater rocky stream. PIT telemetry performances were compared with a conventional hand-capture method, i.e. visual searching and overturning movable stones in the streambed. The mean efficiency of the portable detector (88.2% ± 5.2, s.e.) was significantly higher than hand-capture (51.1% ± 6.4) and the operator progressed, on average, four times faster. Time efficiencies were, on average, 0.92 (±0.15) and 0.12 (±0.04) adult salamanders per minute with the portable detector and by hand-capture, respectively. The efficiency of the portable detector was negatively correlated with the percentage of large stones on the streambed. The time needed to prospect a section was positively correlated with the abundance of PIT-tagged adult salamanders, spring inlets and undercut banks. Because PIT telemetry is less disruptive than hand-capture for both salamanders and their habitat, it is a promising and non-disruptive method for developing studies on the ecology and management of amphibians in shallow waters.

Using PIT technology to study the fate of hatchery-reared YOY northern pike released into shallow vegetated areas

This study uses passive integrated transponder (PIT) technology to analyse the fate of 192 PIT-tagged hatchery-reared young-of-the-year northern pike Esox lucius (mean fork length FL 51.0 mm ± 5.3 S.D.) released into an experimental area located in the Brière Marsh (France), together with 72 untagged individuals for control. Survival and emigration were studied by trapping and using a portable PIT detector from release (20 May) to complete drying out of the grassland (15 June 2005). Only 19.3% and 6.9% of the PIT-tagged and control fish, respectively, successfully emigrated from the experimental area before drying out. Small individuals (FL <50 mm at tagging) suffered a higher mortality rate, and size-dependent effects of cannibalism rather than PIT-tagging procedure on survival were suspected. No evidence of tag loss was found for surviving fish, and individual growth conformed to values reported in literature. The portable PIT antenna detected 71.4% of the PIT-tagged pike in the flooded grassland. More than 30% of tagged fish disappeared from the experimental area throughout the study period, and predation by birds was suspected. Results support the view that more attention should be paid to limiting the detrimental effects of mortality on the stocking success of northern pike.

Apparent Survival and Detection Estimates for PIT‐Tagged Slimy Sculpin in Five Small New Brunswick Streams

AbstractThe slimy sculpin Cottus cognatus is an abundant and widespread benthic fish that inhabits cold lakes and rivers in North America. The objective of this study was to estimate survival and detection probabilities for slimy sculpin in relation to several environmental and biological predictors. Passive integrated transponder (PIT) tags were implanted into 337 adult slimy sculpin in five tributaries of the Kennebecasis River, New Brunswick, Canada. A portable PIT tag antenna was used to search for marked individuals from June 2003 to July 2004. Cormack–Jolly–Seber open population models were used to test several predictions and to estimate apparent survival and detection probabilities. We found that survival was high (73–99%) among sampling events; the average period was about 4 weeks (range, &lt;1–22 weeks). Survival was positively related to fish length and negatively related to maximum stream discharge. The mean detection probability of tagged sculpin was 0.80, but it varied among sampling events and with respect to the minimum electrical current of our antenna and the percentage of boulder substrate at the site. This study demonstrates that a portable PIT tag system can be used in conjunction with capture–mark–recapture models to acquire an understanding of the basic life history characteristics of slimy sculpin and possibly other small‐bodied fish in freshwater systems.

Development and evaluation of portable PIT tag detection units: PITpacks

Portable passive integrated transponder (PIT) technology has been used by biologists to study fish behavior non-invasively. However, the method's efficacy has not been evaluated rigorously. To address this, we evaluated the design and field application of three portable backpack PIT tag units (PITpacks) over three years in Abernathy Creek, Longview, WA. Specifically, we assessed options for PITpack design and construction, PIT tag loss and mortality in steelhead trout following the implantation of 23 mm PIT tags, field efficiency of PITpack surveys and the effect of approaching PITpacks on steelhead trout behavior. Our results indicate that antennas constructed of 14 gauge ribbon cable operated consistently when held at a 45° angle to the water surface. Design modifications reduced equipment weight and made PITpacks easier to use. Read range of optimized PITpacks approached 90 cm off the antenna plane when the antenna and tag were submerged in water. Mortality was higher in 23 mm PIT tagged (1.8%) than in non-PIT tagged (0.5%) fish maintained in the same raceways. Tag loss was estimated to be 7.2%, peaked 4 weeks after implantation, and continued at a lesser rate throughout the 4-month study. Instream use of PITpacks resulted in a consistent survey efficiency of 38% in three separate trials. In addition, behavioral observations of tagged fish revealed minimal disturbance to fish approached by PITpacks. Results show that PITpacks can be applied in small streams to study individual fish behavior with only one collection and handling event (for tagging) and minor further disruption.

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.