External Tags Research Articles

Determination of proteins in hypoxic Müller glia cells by single-cell ICP-MS: The use of a Rh-DNA intercalator for enhanced cell detection

Single cell − inductively coupled plasma-mass spectrometry (sc-ICP-MS) enables the identification and quantification of elements and biomolecules within individual cells. Target proteins can be analyzed by sc-ICP-MS using metal nanoclusters (MNCs)-based immunoprobes, facilitating the detection of low amounts of proteins in each cell. However, for the full implementation of sc-ICP-MS, an effective strategy to enhance the detection of cellular events is required. In this work, the measurement of endogenous elements and two external tags (ruthenium red and Rh-DNA intercalator) was investigated for cell detection. As a proof of concept, the sequential determination of two proteins (hypoxia inducible factor-1α and vascular endothelial growth factor; HIF-1α and VEGF, respectively) in individual human Müller glia cells (MIO-M1) was pursued. Specific antibodies against HIF-1α and VEGF were labelled with AuNCs and IrNCs, respectively. The results demonstrated the advantages of using Rh-DNA intercalator for the detection and discrimination of cellular events by sc-ICP-MS for quadrupole (Q) mass spectrometers. Additionally, applying this analytical method to cultured MIO-M1 cells under hypoxic and to normoxic conditions showcased the ability of sc-ICP-QMS to study hypoxia-induced changes in the cell-to-cell distributions of HIF-1α and VEGF levels.

The first deployments of pop‐up satellite archival tags on black sea bass (Centropristis striata)

AbstractBlack sea bass (Centropristis striata; BSB) are a commercially managed species with an increasing population in the Northwest Atlantic Ocean. Understanding their movement ecology can be difficult due to their wide distribution and ability to inhabit both inshore and offshore reef habitats. BSB have been studied using a range of tagging techniques, and here we present the results of the first deployments of pop‐up satellite archival tags (PSAT) on this species. During 2019 and 2021, we conducted four fishing trips within the southern Mid‐Atlantic Bight region of the NW Atlantic and tagged a total of 30 fish with T‐bar tags and external data loggers, of which 4 received a PSAT and the rest received a Star‐Oddi conductivity–temperature–depth (CTD) archival tag. All PSATs transmitted some data, with short attachment durations (8–32 days) relative to the programmed release of 250 days, and we did not recover a Star‐Oddi tag. External tag attachment techniques need to be examined and improved before continued deployment of larger data loggers on BSB.

Estimating internal transmitter and external tag retention by Walleye in the Laurentian Great Lakes over multiple years

AbstractObjectiveBoth electronic tags (e.g., acoustic and radio transmitters) and conventional external tags are used to evaluate movement and population dynamics of fish. External tags are also sometimes used to facilitate the recovery of internal electronic tags or other instrumentation because healing can make it difficult to identify fish with internal tags based on appearance alone. With both tag types, tag shedding and failure of electronic tags can affect accuracy and precision of study results.MethodsWe used a decade (2011–2021) of recapture data for Walleye Sander vitreus tagged in the Laurentian Great Lakes, where fish were double‐ or triple‐tagged with external tags (T‐bar, loop, or internal anchor tags) and internal acoustic transmitters, to quantify external tag and internal transmitter shedding and transmitter failure rates.ResultIn total, 1125 (33%) Walleye were recovered that had retained at least one external tag or internal transmitter. No confirmed cases of transmitter shedding were observed; 15 of 899 transmitters (2%) that were checked for functionality failed prior to the expected battery expiration. The retention of external T‐bar tags 1 year after release differed depending on whether the tag was placed anterior or posterior to the secondary dorsal fin (anterior, fish length = 420 mm: 73% retention; anterior, fish length = 700 mm: 73%, posterior: 63%) but was <26% after 4 years for both tag positions and fish sizes. Internal anchor tags had an 88% 1‐year retention probability and 81% 4‐year retention probability. Loop tags had the highest 1‐year retention (89%) but after 4 years retention (28–34% depending on agency) was comparable to that of T‐bar tags.ConclusionBetter understanding of tag retention characteristics through long‐term tagging studies such as this can inform study design, be considered in model design, and ultimately improve inferences from mark–recapture studies.

Sensory Considerations for Emerging Textile Applications

Textiles are increasingly playing a role as a therapeutic medium in the disability field as well as in everyday life. This paper aims to review the literature on the relationship between textiles and sensory integration or sensory preferences in the general population. A brief literature review was conducted using PubMed (MEDLINE), SCOPUS, and Google Scholar. The review of the current literature highlights some key themes in the literature, including the indication that adaptive and sensory clothing design requires consideration of the textiles and fabrics being used, the functionality and appearance of garments, and affordability and access. The evidence suggests that clothing design should utilize soft fabrics which are seamless, have limited external tags, support social participation and functional engagement in daily activities, and are accessible.

Ruthenium-catalyzed intermolecular alkene-alkyne couplings in biologically relevant media.

Cationic cyclopentadienyl Ru(ii) catalysts can efficiently promote mild intermolecular alkyne-alkene couplings in aqueous media, even in the presence of different biomolecular components, and in complex media like DMEM. The method can also be used for the derivatization of amino acids and peptides, therefore proposing a new way to label biomolecules with external tags. This C-C bond-forming reaction, based on simple alkene and alkyne reactants, can now be added to the toolbox of bioorthogonal reactions promoted by transition metal catalysts.

A new non-invasive tagging method for leopard coral grouper (Plectropomus leopardus) using deep convolutional neural networks with PDE-based image decomposition

External tagging methods can aid in the research of leopard coral grouper (Plectropomus leopardus) in terms of its spatio-temporal behavior at population and individual scales. However, due to the strong exclusion ability and the damage to the body wall of P. leopardus, the retention rate of traditional invasive tagging methods is low. To develop a non-invasive identification method for P. leopardus, we adopted a multiscale image processing method based on matched filters with Gaussian kernels and partial differential equation (PDE) multiscale hierarchical decomposition with the deep convolutional neural network (CNN) models VGG19 and ResNet50 to extract shape and texture image features of individuals. Then based on image features, we used three classifiers Random forest (RF), support vector machine (SVM), and multilayer perceptron (MLP)) for individual recognition on sequential images of P. leopardus captured for 50 days. The PDE, ResNet50 and MLP combination obtained a maximum accuracy of 0.985 ± 0.045 on the test set. For individual temporal tracking recognition, feature extraction and model training were performed using images taken in 1-20 days. The classifier could achieve an accuracy of 0.960 ± 0.049 on the test set consisting of images collected in the periods of 20-50 days. The results show that CNNs with the PDE decomposition can effectively and accurately identify P. leopardus.

Sublethal Effects of Acoustic Dummy Tag Implantation and External Tags in Silver Carp

AbstractTelemetry data collected via internally implanted transmitters are commonly used to monitor and manage invasive Silver Carp Hypophthalmichthys molitrix. However, the extent to which posttagging effects may influence fish behavior is generally overlooked in telemetry studies. Moreover, internal telemetry tags are often combined with an external tag that can also affect fish growth and survival. This study used two pond experiments to (1) evaluate the temporal effects of internal telemetry tags, external jaw tags, and the combination of the two tags on survival, relative weight, growth, and inflammation; and (2) compare the effects of two external tag types (jaw and loop tags) on Silver Carp. Response variables were evaluated at three time points: 1, 2, and 5 months posttagging. Growth and relative weight were lower in fish that received jaw tags than in the control group or in fish that received internal tags only; however, growth was different at 1 month posttagging but not at 2 months posttagging, indicating potential compensatory growth. Shedding rate of internal tags was 14%; after 5 months, inflammation was absent and tags were encapsulated in tissue. Survival was similar between loop‐ and jaw‐tagged fish (73%), although growth was lower in jaw‐tagged fish. Results indicate that survival effects and sublethal effects of telemetry tagging may be temporary, and researchers should examine detection data from within 1–2 months of tagging for possible postsurgery effects. Jaw tags reduced growth, and loop tags had reduced retention; therefore, further evaluation of alternative external tags is needed to optimize telemetry studies focused on Silver Carp. Additionally, researchers need to carefully evaluate which external tag to use to facilitate the returns of more expensive acoustic telemetry tags and whether external tags are necessary in a particular case.

Dispersal and Survival of Captive-Reared Threatened Fishes in a Tonle Sap Lake Reserve

The Tonle Sap Lake in Cambodia supports several species of threatened megafish and contains one of the largest networks of freshwater fish reserves in the world. Despite these traits, this system remains understudied in terms of its utility for endangered fish conservation and restoration. This study was the first of a series of planned fish releases designed to test the effectiveness of conservation supplementation programs in the Tonle Sap Lake. In March 2022 (during the dry season), 1582 captive-reared fishes, including 1538 striped catfish Pangasianodon hypopthalmus, 42 giant barb Catlocarpio siamensis, and two Mekong giant catfish Pangasianodon gigas, were tagged and released into a 986-hectare fish reserve to assess post-release dispersal and survival. Brightly colored external tags with unique identification numbers were used to facilitate tag returns. A high-profile release event was held to raise awareness about the activity, bringing attention to the importance of fish reserves and endangered species conservation, and disseminating information about the research and tag return and reward program. This, in concert with other efforts, served to be an important education and outreach tool and increased tag return rates. We found that mortality from fishing was rapid and very high. Nineteen percent of released fishes were recaptured in the first 2 days after the fish release, and 46% were recaptured by day 83 after the release, indicating intense fishing pressure on the Tonle Sap Lake fisheries. Eighty percent of recaptured fishes were caught in stationary gill nets, most within 10 km of the release site. Fishing mortality rates were independent of fish size or source (pond-reared or cage-reared). Environmental DNA (eDNA) was found to be capable of detecting each of these species’ presence in the water at the release site and could prove to be a useful tool for endangered species monitoring and restoration. Future research should explore alternative release timing, release location, and other methods of increasing post-release survival. Ultimately, underlying sources of mortality, especially fishing, will need to be addressed for conservation supplementation programs to succeed in the Tonle Sap Lake. Conservation supplementation should not be viewed as a substitute for more fundamental conservation measures, such as maintenance of environmental flows, preservation of ecological connectivity, and science-based fisheries management.

Accelerating PROTAC drug discovery: Establishing a relationship between ubiquitination and target protein degradation

PROTACs have emerged as a new class of drugs that can target the “undruggable” proteome by hijacking the ubiquitin proteasome system. Despite PROTACs’ success, most current PROTACs interface with a limited number of E3 ligases, hindering their expansion to many challenging therapeutic uses. Currently, PROTAC drug discovery relies heavily on traditional Western blotting and reporter gene assays which are insensitive and prone to artifacts, respectively. New reliable methods to monitor true PROTAC function (i.e., ubiquitination and subsequent degradation of targets at physiological expression levels) without external tags are essential to accelerate the PROTAC discovery process and to address many unmet therapeutic areas. In this study, we developed a new high-throughput screening technology using “TUBEs” as ubiquitin-binding entities to monitor PROTAC-mediated poly-ubiquitination of native target proteins with exceptional sensitivity. As a proof of concept, targets including BRD3, Aurora A Kinase, and KRAS were used to demonstrate that ubiquitination kinetics can reliably establish the rank order potencies of PROTAC with variable ligands and linkers. PROTAC-treated cell lysates with the highest levels of endogenous target protein ubiquitination - termed “UbMax” - display excellent correlations with DC50 values obtained from traditional Western blots with the added benefits of being high throughput, providing improved sensitivity, and reducing technical errors.

The effect of externally attached archival data loggers on the short-term dispersal behaviour and migration speed of European eel (Anguilla anguilla L.)

BackgroundExternally attached archival data logging tags are increasingly used to unravel migration routes of fish species at sea. Due to the relatively large size of the tags, their application on seaward migrating anguillid eels often forms a challenge in terms of feasibility and impact on the eel’s swimming performance. In this study, we investigated the impact of externally attached pop-up data storage tags (PDSTs) on the departure direction, time spent at the release location and ground speed of European eels (Anguilla anguilla).ResultsWe tagged 66 eels with internal acoustic transmitters of which half of the eels were additionally tagged with externally attached PDSTs. A network of acoustic receivers allowed us to analyse if the dispersal behaviour (i.e. residence time and departure direction) from the release site differed between eels tagged with and without the PDSTs. In addition, we tracked the eels for ca. 83 km in the marine environment and determined their migration speed. The results showed no differences between eels tagged with or without external PDSTs in respect of the external tagging effect on residence time (n = 60), departure direction at the release site (n = 60) or on the migration speed (n = 20).ConclusionsWe conclude that the impact of the PDSTs is minimal on these metrics for at least the first part of the marine migration. While these field-based findings suggest that anguillid eels may be largely unaffected by the applied PDSTs, we recognize that more research is needed in both the field and the laboratory to study the impact of PDSTs and externally attached tags in general on fish swimming performance and energy expenditure. This can help interpret the results from the field, but also aid developing more hydrodynamic tag shapes or improved attachment methods.

Short-term response of research activities on white shark behaviour

Context Researchers studying animals need to ensure that sampling procedures and the methods they use are as harmless and non-disruptive as possible, particularly when their focal species are threatened or protected. White sharks (Carcharodon carcharias) are Vulnerable under the IUCN Red List, protected globally, and are frequently studied by marine ecologists. Aims To assess white shark responses to research activities (i.e. tagging and biopsy procedures, and electric deterrent trials) conducted at the Neptune Islands Group Marine Park (South Australia, Australia). Methods Trends in shark residency following research activities were assessed by comparing shark abundance (number of sharks detected by acoustic receivers and sighted by cage-diving operators) before, during, and after scientific expeditions, and to natural fluctuations in the absence of research activities using 8 years (2013–2021) of acoustic tracking and daily sighting reports from a wildlife tourism industry. Key results Number of white sharks and residency decreased after sampling. However, changes observed following research activities were similar to natural fluctuations, suggesting that these changes reflected natural variations rather than being due to sharks responding negatively to the research activities. Conclusions Our study showed that external tagging, biopsies, or deterrent trials do not affect short- and long-term residency or abundance of white sharks, probably owing to the research activities being minimally intrusive and to sharks having efficient immune systems and remarkable ability to heal from injuries. Implications Re-evaluating study methods forms part of the researcher’s responsibilities to ensure best practice and to abide by national and international codes for the care and use of animals for scientific purposes.

A PIT‐tag–based method for measuring individual bait uptake in small mammals

Abstract Rodents and other small mammals cause an increasing number of negative economic and environmental impacts worldwide. In the UK, the non‐native grey squirrel has a significant impact on the forestry industry and has caused the decline of the native red squirrel. Baits are used to deliver biocides and contraceptives to reduce overabundant wildlife populations and as vehicles for vaccines to control disease outbreaks. Bait‐delivered contraceptives are also being developed to manage grey squirrel populations in the UK. The effectiveness of bait‐delivered drugs on wildlife populations depends on the amount of bait consumed by individuals over time; therefore, it is important to understand individual level bait uptake in order to optimize delivery methods. Passive integrated transponder (PIT) tags are increasingly used to mark and monitor animal behaviour as they are cost‐effective, have minimal negative welfare impacts and have a lower tag loss rate than external tags, particularly in small animals. The aim of this study was to design and test a novel bait hopper equipped with a PIT‐tag reader and bait‐weighing device, to record bait uptake by individual grey squirrels for optimizing the delivery of a contraceptive bait. The hopper was designed to overcome some of the limitations of traditional PIT‐tag systems, by improving battery life and the quality and quantity of data collected in the field. In captive trials, the hopper proved to be highly effective at recording feeding visits by squirrels, as 95% of the visits could be attributed to a PIT‐tag record. The hoppers measured the amount of bait removed per feeding visit to an accuracy of 0.1 g, with 97% of the bait taken from six hoppers attributed to a PIT‐tag ID. In a field trial, the hoppers were effective at recording the feeding visits by grey squirrels in two woods, with 47 of the 51 PIT‐tagged grey squirrels entering the hoppers. The adaptability of the hopper design means that it has wider applications for wildlife management; in particular, efficacy studies for bait‐delivered substances in the context of wildlife disease control and/or population reduction.

Dog Identification Method Based on Muzzle Pattern Image

Currently, invasive and external radio frequency identification (RFID) devices and pet tags are widely used for dog identification. However, social problems such as abandoning and losing dogs are constantly increasing. A more effective alternative to the existing identification method is required and the biometrics can be the alternative. This paper proposes an effective dog muzzle recognition method to identify individual dogs. The proposed method consists of preprocessing, feature extraction, matching, and postprocessing. For preprocessing, proposed resize and histogram equalization are used. For feature extraction algorithm, Scale Invariant Feature Transform (SIFT), Speeded Up Robust Features (SURF), Binary Robust Invariant Scaling Keypoints (BRISK) and Oriented FAST, and Rotated BRIEF (ORB) are applied and compared. For matching, Fast Library for Approximate Nearest Neighbors (FLANN) is used for SIFT and SURF, and hamming distance are used for BRISK and ORB. For postprocessing, two techniques to reduce incorrect matches are proposed. The proposed method was evaluated with 55 dog muzzle pattern images acquired from 11 dogs and 990 images augmented by the image deformation (i.e., angle, illumination, noise, affine transform). The best Equal Error Rate (EER) of the proposed method was 0.35%, and ORB was the most appropriate for the dog muzzle pattern recognition.

CMOS THz-ID: A 1.6-mm² Package-Less Identification Tag Using Asymmetric Cryptography and 260-GHz Far-Field Backscatter Communication

This article presents an ultra-small, high-security identification tag that is entirely built in a CMOS chip without external components. The usage of backscatter communications at 260 GHz enables full integration of a 2 × 2 patch antenna array. For chip compactness and minimum interference caused by direct wave reflection, the backscatter signal is frequency-shifted by 2 MHz and radiated with cross polarization from the same antenna array. Such a configuration also, for the first time for RF tags, enables beamsteering for enhanced link budget. For authentication and secure wireless data transmission, the tag also integrates a compact elliptic-curve-cryptography (ECC) dedicated processor, which is based on a narrow-strong private identification protocol. The presented tag has a peak power consumption of 21 μW and can be powered by a chip-wide array of photodiodes and a DC-DC converter. Using a low-cost 65-nm bulk CMOS technology, the terahertz (THz) ID chip has an area of only 1.6 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and demonstrates the measured downlink speed of 100 kb/s and the upload speed of 2 kb/s across 5-cm distance from the reader. The tag-reader authentication/communication protocol is fully demonstrated using external tag power and partially demonstrated using the tag-integrated photo-voltaic powering. The tag size is the smallest among all prior radio-frequency identifications (RFIDs) using far-field communications.

A Trapping Survey Targeting Head-Started Alligator Snapping Turtles in Southwest Louisiana

AbstractThe alligator snapping turtle Macrochelys temminckii is the largest freshwater turtle in North America and humans seek it as a food source, primarily in Louisiana. Scientists point to decades of intensive commercial harvest of alligator snapping turtles as a cause of population declines. The Louisiana Department of Wildlife and Fisheries initiated a head-start program for alligator snapping turtles and released 53 head-started juveniles at seven sites along an approximately 5.7-km stretch of Bundick Creek in southwest Louisiana between November 2015 and October 2016. Before release, department personnel measured, weighed, and marked all alligator snapping turtles with both an internal passive integrated transponder tag and a numbered external tag. In 2018, the U.S. Geological Survey initiated a turtle trapping survey at those seven release sites targeting the head-started alligator snapping turtles. In 1 wk of trapping effort at each site, we recorded 69 turtle captures comprising seven species, including 15 alligator snapping turtles (representing 12 individuals). Of those 12 individuals, 8 were head-started juveniles and 4 were native to the creek. A landowner captured an additional head-started juvenile alligator snapping turtle during our trapping and we took measurements before its release. A minimum of 17% of head-started alligator snapping turtles survived since release, and we trapped most captured head-started individuals near their release site; the captured individuals exhibited growth consistent with other studies, indicating acclimatization to their new environment. Three head-started alligator snapping turtles had their external tags entangled in the net mesh, and two of these turtles drowned. An additional two head-started individuals lost their external tags in the natural environment prior to their capture in this study. The Louisiana Department of Wildlife and Fisheries discontinued the use of external tags based on our findings, as these tags were detrimental to the health of head-started turtles.

Adult Sockeye Salmon Gastrically Tagged Near Spawning Grounds Exhibit Lower Survival Rates throughout the Spawning Period than Externally Tagged Conspecifics

AbstractTelemetry is a common tool for studying the behavior and fate of migrating adult Pacific salmon Oncorhynchus spp., yet few field studies have compared behavior and fate associated with different tagging techniques. In this study, adult Harrison River (British Columbia) Sockeye Salmon O. nerka were captured in their natal river near spawning areas, radio‐tagged by gastric insertion or external attachment in the dorsum, and released. Tagging occurred on 5 d spread over 3–8 weeks prior to spawning, thus encompassing fish in varying stages of maturity and freshwater residency. Tagged individuals were monitored over the spawning season by using fixed receiver stations and mobile tracking. The probability of fish moving upstream or downstream of the tagging site within 35 h of tagging was a function of tagging date but not tag type. Tag type significantly influenced fate, with almost twice as many externally tagged fish (41.6%; 42 of 101) surviving to reach spawning areas compared to gastrically tagged fish (22.4%; 21 of 94). The number of active externally tagged fish in the Harrison River system was consistently greater than the number of active gastrically tagged fish that received tags on the same date for four of the five tagging dates. External tag attachment may be a better approach than gastric insertion for studies that tag adult salmon near or on spawning areas.

Efficiency and Suitability of the Fish Passages of River Ceyhan, Turkey

The efficiencies of the two fish passages of River Ceyhan (Turkey) were investigated by using trap catches, external tags (T-bar anchor tags), PIT telemetry and radio telemetry. According to the results of the study, the pool and weir type fish passage were not effective; no fish entered the trap in this fish passage. Further, it was observed that none of the 50 external tagged fishes, 44 PIT-tagged fishes, and 47 radio-tagged fishes passed through this fish passage. A total of 900 Capoeta damascina and 520 Alburnus adanensis entered the trap installed in the vertical slot fish passage. A relationship was found between the gender ratio of the migratory C. damascina and their migration times. Fish passage performance was different according to the applications. These differences in fish passage success among the applications originated from the sizes of the tagged fish. Because the sizes of the radio-tagged fish were much larger than that of the external tagged fish and PIT-tagged fish so the success of the fish passage according to the radio telemetry was estimated higher than that of the other applications. The further passing ratio of the fish over 20 cm in length was higher than that of the small individuals.

Novel method of tagging the kuruma prawn Penaeus japonicus with a trans-molting retentive external eye (TRAMORE) tag

An easily applicable, economical, and reliable tagging method, without risk to consumers, is required for the kuruma prawn Penaeus japonicus. This report describes the development of external tags for the kuruma prawn. Two types of external tag, differing slightly in form, were developed. Tests were performed to determine whether these external tags were retained after molting and whether the tagging method affected survival and growth in the laboratory. One type of external tag, with a hole of diameter 1.5 mm, was applied to the eyestalks of juvenile prawns approximately 45 mm in body length (BL). Despite repeated molting, these tags were retained at least until the prawns grew to BL 140 mm. Therefore, these tags were called trans-molting retentive external eye (TRAMORE) tags. The trackable size range with the TRAMORE tag, with a hole of diameter 1.5 mm, (<140 mm BL) covered approximately 50 % of kuruma prawns caught in Seto Island Sea, Japan, one of its main fishing grounds. The TRAMORE tag had no impact on the survival, growth, or molting frequency of juveniles. The second type of TRAMORE tag, with a hole of diameter 2.8 mm, was not shed during molting of individuals of BL ranging from 82.7 mm to 216 mm BL. Approximately 100 % of kuruma prawns caught in Seto Island Sea were of this size. The TRAMORE tag would contribute to kuruma prawn stock enhancement programs and investigations of key aspects of its ecology.

Evaluating the effect of dorsal muscle biopsies on adult Atlantic salmon growth and marine return rates.

Increasing conservation and animal-welfare concerns have driven the development of non-lethal sampling of fish populations, with the use of muscle tissue biopsies now being routinely applied as a sampling method in the wild. Crucial to the success of non-lethal sampling, however, is an evaluation of the short- and long-term consequences of the treatment and ultimately the determination of how these may affect organism mortality and other fitness-related traits. The current study evaluated the use of a dorsal muscle biopsies on post-spawned Atlantic salmon emigrating to sea and undertaking a 2-month long-feeding migration before returning to spawn. Using mark-recapture, return rates and growth were compared between fish that were biopsied and externally tagged, and a control group tagged only with external tags. The biopsy treatment showed no lasting effects on fish as estimated from the two key fitness-related parameters. Results, therefore, suggest the technique can be more widely applied to gather information on marine migrating Atlantic salmon and other anadromous fishes that can be intercepted as they descend and ascend rivers during seasonal migrations. Coupled with modern tagging technologies, the use of biopsies may facilitate an improved understanding of movement and its consequences in terms of feeding patterns and growth.

Wanted dead or alive: characterizing likelihood of juvenile Steller sea lion predation from diving and space use patterns

ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 40:357-367 (2019) - DOI: https://doi.org/10.3354/esr00999 ESR Special: Biologging in conservation Wanted dead or alive: characterizing likelihood of juvenile Steller sea lion predation from diving and space use patterns Amanda M. Bishop1,*, Alexandra K. Dubel2, Renae Sattler3, Casey L. Brown4, Markus Horning1 1Alaska SeaLife Center, Seward, AK 99664, USA 2Florida State University, Tallahassee, FL 32306, USA 3Alaska Department of Fish and Game, Palmer, AK 99645, USA 4Oregon Department of Fish and Wildlife, La Grande, OR 97850, USA *Corresponding author: amybi@alaskasealife.org ABSTRACT: Understanding linkages between behaviors and mortality risk is critical for managing populations. Juveniles constitute a particularly vulnerable life stage, with growing evidence that within stages, individual strategies may be associated with greater predation risk and mortality. These forms of predator-prey dynamics are rarely explored in marine environments due to difficulties in confirming vital status of individuals, and the lack of data sets that link mortality to behavior. We analyzed 2 concurrently collected data sets for juvenile Steller sea lions Eumetopias jubatus in the Gulf of Alaska to examine associations between mortality and specific behavioral patterns. Forty-five juvenile Steller sea lions were instrumented with external satellite tags and internally implanted vital rate transmitters (LHX tags). From 2005 through 2018, 25 juveniles remained alive and 20 died (18 confirmed predation). Using a binomial generalized linear mixed-effects model, we tested whether the probability of individual mortality was associated with seasonally specific dive patterns (time wet, dive depth) or horizontal movement patterns (home range size, average trip distance). Additionally, in 3 cases, external tags were transmitting until death. To examine links between fine-scale ante-mortem behavioral patterns and predation susceptibility, we compared dive patterns recorded during the last 3 d of data transmissions (both for animals which survived and for those which died) to dive patterns recorded during other periods at sea. Results suggest individuals that spent more time dry or dove shallower had a greater mortality probability, which could reflect foraging tactics of predators. This study highlights the effectiveness of combining multiple telemetry systems for exploring the vulnerability of individuals to the consumptive effects of predators. KEY WORDS: Predation · Bio-logging · Diving behavior · Eumetopias jubatus · Risk · Marine mammal Full text in pdf format Supplementary material PreviousNextCite this article as: Bishop AM, Dubel AK, Sattler R, Brown CL, Horning M (2019) Wanted dead or alive: characterizing likelihood of juvenile Steller sea lion predation from diving and space use patterns. Endang Species Res 40:357-367. https://doi.org/10.3354/esr00999 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 40. Online publication date: December 19, 2019 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2019 Inter-Research.