Complete tag loss in capture–recapture studies affects abundance estimates: An elephant seal case study

Malcolm‐White, Emily; McMahon, Clive R.; Cowen, Laura

doi:10.1002/ece3.6052

Cited by 11 publications

(17 citation statements)

References 27 publications

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“…Therefore, data‐driven parameter redundancy in the GJSTL models disappear when there is a large n . We note that in this case of low survival and capture rates, there are large biases in parameter estimates (Malcolm‐White et al., 2020); these biases are somewhat improved by high tag retention rates.…”

Section: Resultsmentioning

confidence: 77%

Parameter redundancy in Jolly‐Seber tag loss models

Cai

Yurchak

Cole

et al. 2021

Ecology and Evolution

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Capture–recapture experiments are conducted to estimate population parameters such as population size, survival rates, and capture rates. Typically, individuals are captured and given unique tags, then recaptured over several time periods with the assumption that these tags are not lost. However, for some populations, tag loss cannot be assumed negligible. The Jolly‐Seber tag loss model is used when the no‐tag‐loss assumption is invalid. Further, the model has been extended to incorporate group heterogeneity, which allows parameters to vary by group membership. Many mark–recapture models become overparameterized resulting in the inability to independently estimate parameters. This is known as parameter redundancy. We investigate parameter redundancy using symbolic methods. Because of the complex structure of some tag loss models, the methods cannot always be applied directly. Instead, we develop a simple combination of parameters that can be used to investigate parameter redundancy in tag loss models. The incorporation of tag loss and group heterogeneity into Jolly‐Seber models does not result in further parameter redundancies. Furthermore, using hybrid methods we studied the parameter redundancy caused by data through case studies and generated tag histories with different parameter values. Smaller capture and survival rates are found to cause parameter redundancy in these models. These problems resolve when applied to large populations.

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Section: Resultsmentioning

confidence: 77%

Parameter redundancy in Jolly‐Seber tag loss models

Cai

Yurchak

Cole

et al. 2021

Ecology and Evolution

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“…Most model developments to account for mark loss have focussed on the Jolly-Seber model (Jolly, 1965;G. Seber, 1965) for abundance estimates, where mark loss and recycling are prone to generate serious biases (Malcolm-White et al, 2020). The loss of the mark remains largely unconsidered despite an increasing use of MSCJS models in ecology, demography, management and conservation (Huntsman et al, 2020;Melnychuk et al, 2017).…”

Section: Discussionmentioning

confidence: 99%

Mark loss can strongly bias demographic rates in multi-state models: a case study with simulated and empirical datasets

Touzalin¹,

Petit²,

Cam

et al. 2022

Preprint

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The development of methods for individual identification in wild species and the refinement of Capture-Mark-Recapture (CMR) models during the past decades has greatly improved the assessment of population demographic rates to answer ecological and conservation questions. In particular, multistate models, with their flexibility for the analysis of complex study systems, have become popular in the ecological community. However, despite the extensive use of these models, little attention has been paid to the effect of common violations of the CMR model assumptions, such as mark loss and the often-associated recycling of remarked individuals. To explore this knowledge gap we used a wide range of simulation scenarios reflecting frequently encountered real case studies inspired from the survival rates of 700 vertebrates' species. We estimated the effects of mark loss and recycled individuals on parameter estimates using a multi-state Cormack-Jolly-Seber (MSCJS) framework. We explored parameter bias through simulations of a metapopulation system with different capture and survival rates. We also illustrated how mark loss can be easily estimated and accounted for using an empirical long-term (10 years) CMR dataset of bats, individually identified using both PIT tag technology as marks that can be lost, and multi-locus genotypes as "permanent marks". The results from our simulated scenarios demonstrated that the occurrence of bias and the parameters concerned were highly dependent on the study system, and no general rules on parameter behaviour can be established a priori. The model structure and the interdependency among parameters make it challenging to predict how bias could affect estimates. Our results highlight the need to assess the effect of mark loss when using MSCJS models. Ignoring such violations of model assumptions can have important implications for ecological inferences and conservation policies. In general, the use of permanent marks (e.g. genotype), should always be preferred when modelling of population dynamics and if not possible, combining two types of temporary marks (e.g. PIT tags, bands) should be considered.

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“…This approach allowed us to include all captured individuals in the model without the cost and burden of physically marking (i.e., PIT tagging) every fish. However, because untagged individuals may have unknowingly been handled multiple times during the study period, the super-population estimate generated by the POPAN model is potentially inflated (Malcolm-White et al 2020) and not presented herein. Rather, we focus on the estimates of steelhead abundance generated for each sampling occasion which were expected to be unbiased (Schwarz and Arnason 1996;Frechette et al 2016;Osterback et al 2018).…”

Section: Steelhead Abundance Growth and Condition Factormentioning

confidence: 99%

Spatiotemporal Variability in Environmental Conditions Influences the Performance and Behavior of Juvenile Steelhead in a Coastal California Lagoon

Bond

Kiernan

Osterback

et al. 2021

Estuaries and Coasts

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In California (USA), seasonal lagoons provide important oversummer rearing habitat for juvenile steelhead trout (anadromous Oncorhynchus mykiss). However, key water quality parameters such as temperature and dissolved oxygen concentration can periodically approach or exceed the physiological tolerances of steelhead during the protracted dry season. A field study employing distributed temperature sensing technology, water quality monitoring, habitat mapping, and mark-recapture sampling was conducted to examine how shifting environmental conditions affected the performance and behavior of juvenile steelhead in the Scott Creek estuary/lagoon (Santa Cruz County). Abiotic conditions were driven by episodic inputs of seawater to the typically freshwater lagoon. During midsummer, the water column was vertically stratified which reduced suitable lagoon rearing habitat by approximately 40%. Nevertheless, steelhead abundance, growth, and condition factor were high during the summer and decreased in autumn following lagoon destratification and cooling. Unlike previous work, this study identified limited emigration from the lagoon to riverine habitat during the summer. Instead, juvenile steelhead exhibited crepuscular movement patterns within the lagoon, with peaks in upstream (to upper lagoon habitat) and downstream (to lower lagoon habitat) movement occurring at dawn and dusk, respectively. This study underscores that habitat complexity and connectivity are critical for juvenile steelhead production and persistence and provides insight into steelhead habitat use and behavior in seasonal lagoons.

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Complete tag loss in capture–recapture studies affects abundance estimates: An elephant seal case study

Cited by 11 publications

References 27 publications

Parameter redundancy in Jolly‐Seber tag loss models

Parameter redundancy in Jolly‐Seber tag loss models

Mark loss can strongly bias demographic rates in multi-state models: a case study with simulated and empirical datasets

Spatiotemporal Variability in Environmental Conditions Influences the Performance and Behavior of Juvenile Steelhead in a Coastal California Lagoon

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