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In this study, we tested the applicability of three common methods of absolute abundance estimation—Peterson, Bailey and Jolly‐Seber—to Ixodes persulcatus ticks based on mark‐release‐recapture data. The ticks were collected by flagging during the seasonal activity peak of the ticks in the mid‐taiga zone of Karelia (62.0697°N, 33.9614°E). In total, 108 females and 92 males of I. persulcatus were marked. The marked individuals were captured 161 times before the end of the study period with their proportion in the samples reaching 50%. Females were recaptured more often than males, 105 versus 56 times. Estimates of adult tick abundance ranged from 0.4 to 2 specimens per m2 depending on the calculation method. The obtained estimates of absolute abundance varied unpredictably depending on the length of the intervals between capture sessions and showed no significant correlations with the number of ticks collected by flagging. The choice of the method of tick abundance estimation mainly depends on the study aims. The Petersen method may be useful for quick estimates of local tick abundance, whereas the Jolly‐Seber method allows an estimation of the absolute abundance during the entire period of the tick activity. Individual marking of ticks may improve the accuracy of the estimates. [ABSTRACT FROM AUTHOR]

Central California coho salmon (Oncorhynchus kisutch) are endangered and steelhead (O. mykiss) are threatened under the U.S. Endangered Species Act. As part of local monitoring efforts, Passive Integrated Transponders (PIT tags) are used in population biology and marine survival studies of these stocks. Since 2006, PIT tags have been recovered on Año Nuevo Island (ANI), an important breeding site for several species of seabirds and marine mammals. The objective of this study was to assess magnitude and effects of avian predation on juvenile salmonids in central California. Objectives were accomplished by 1) identifying predators, timing of predation, and quantifying predation using PIT tag recoveries and Mark-Recapture modeling, and 2) using behavior of a predator (the Western Gull) to examine susceptibility of juvenile salmonids to predation. Between 2006 and 2010, 252 unique PIT tags were recovered on ANI in areas that indicate Western Gulls were the primary predator depositing tags on ANI. Predation by gulls occurred during downstream migration of juvenile salmonids or immediately following ocean entry. Mark-Recapture modeling indicated PIT tags from 1-4% of tagged salmonids were deposited on ANI from watersheds in central California. Minimal temporal overlap between gulls and salmonids occurred at area watersheds, and observation of predation was rare; however, predation was 100% when overlap occurred. Predation by Western Gulls was an appreciable source of mortality for central California salmonids and should be considered in future management plans for these species.

This work is concerned with the analysis of marketing data on the activation of applications (apps) on mobile devices. Each application has a hashed identification number that is specific to the device on which it has been installed. This number can be registered by a platform at each activation of the application. Activations on the same device are linked together using the identification number. By focusing on activations that took place at a business location, one can create a capture-recapture dataset about devices, that is, users, that "visited" the business: the units are owners of mobile devices and the capture occasions are time intervals such as days. A unit is captured when she activates an application, provided that this activation is recorded by the platform providing the data. Statistical capture-recapture techniques can be applied to the app data to estimate the total number of users that visited the business over a time period, thereby providing an indirect estimate of foot traffic. This article argues that the robust design, a method for dealing with a nested mark-recapture experiment, can be used in this context. A new algorithm for estimating the parameters of a robust design with a fairly large number of capture occasions and a simple parametric bootstrap variance estimator are proposed. Moreover, new estimation methods and new theoretical results are introduced for a wider application of the robust design. This is used to analyze a dataset about the mobile devices that visited the auto-dealerships of a major auto brand in a U.S. metropolitan area over a period of 1 year and a half. Supplementary materials for this article, including a standardized description of the materials available for reproducing the work, are available as an online supplement. [ABSTRACT FROM AUTHOR]

The development of sophisticated mark-recapture models over the last four decades has provided fundamental tools for the study of wildlife populations, allowing reliable inference about population sizes and demographic rates based on clearly formulated models for the sampling processes. Mark-recapture models are now routinely described by large numbers of parameters. These large models provide the next challenge to wildlife modelers: the extraction of signal from noise in large collections of parameters. Pattern among parameters can be described by strong, deterministic relations (as in ultrastructural models) but is more flexibly and credibly modeled using weaker, stochastic relations. Trend in survival rates is not likely to be manifest by a sequence of values falling precisely on a given parametric curve; rather, if we could somehow know the true values, we might anticipate a regression relation between parameters and explanatory variables, in which true value equals signal plus noise. Hierarchical models provide a useful framework for inference about collections of related parameters. Instead of regarding parameters as fixed but unknown quantities, we regard them as realizations of stochastic processes governed by hyperparameters. Inference about demographic processes is based on investigation of these hyperparameters. We advocate the Bayesian paradigm as a natural, mathematically and scientifically sound basis for inference about hierarchical models. We describe analysis of capture-recapture data from an open population based on hierarchical extensions of the Cormack-Jolly-Seber model. In addition to recaptures of marked animals, we model first captures of animals and losses on capture, and are thus able to estimate survival probabilities w (i.e., the complement of death or permanent emigration) and per capita growth rates f (i.e., the sum of recruitment and immigration rates). Covariation in these rates, a feature of demographic interest, is explicitly described in the model.

A short-term Jolly–Seber mark-recapture model experiment is described. This experiment was aimed at estimating the rate of catch per unit effort (CPUE) and the catchability coefficient (q) of the Atlantic blue crab (Callinectes sapidus) in the fishing port of Sisal, Yucatan, Mexico. To estimate the local population size, 52 traps were deployed along four transects located in a coastal capture area of 3600 m−2. The CPUE and q were compared between the daily mark-recapture Jolly–Seber experiment and the bi-monthly (carried out every 2 months) samplings. The average abundance was estimated at 3475 individuals. All three suggested scenarios, applied to estimate densities, gave similar estimates, i.e. 0.0386, 0.0350, 0.0365 crabs m−2 for the first (Previously Cited Attraction Radius), second (CPUE per transect) and third (Catchability-Density Relationship), respectively. Based on the latter scenario, densities ranged from 27,900 (annual average) to 36,500 (Spring) crabs km−2. The average CPUE of the daily mark-recapture experiment was estimated at 1.96 crabs trap−1, whereas the average bi-monthly CPUE was estimated at 1.13 crabs trap−1. The q (per trap) was estimated at 0.0186 for the daily mark-recapture experiment and at 0.0247 for the bi-monthly sampling. Both catchability and CPUE increased in individuals whose size ranged between 110 and 170 mm CW. However, no significant difference (ANCOVAs) was found between the daily and bi-monthly samplings neither in CPUE nor in catchability. The use of both mark-recapture data and the Jolly–Seber model proved to be a fast and reliable method for estimating the abundance and catchability of Atlantic blue crab. [ABSTRACT FROM AUTHOR]

Studies on the diversity and population dynamics of euglossine bees in forest formations of the Brazilian savanna can be notably informative considering that most species are forest-dependent. The current study aimed to estimate the diversity and population size of euglossine bees using short-term surveys and the mark–recapture method. We also compared short-term surveys with monthly surveys over a 1-year period (long-term surveys) to assess the species diversity. The study occurred in seven forest formations of the Brazilian savanna. We collected 14 species and marked 375 males but recaptured only 23 (6.1%). The population size ofEuglossabees ranged from 111.1 ± 34.4 to 1384.5 ± 384.6 males. The diversity indices achieved through the short-term surveys were similar to or higher than those obtained from long-term studies. The low recapture rate of euglossine males seems to be the result of their long-distance dispersal capacity. We also proposed that short-term surveys be viewed as a favourable alternative to long-term studies on diversity estimation and that euglossine bees can occur in small populations in some forest formations studied. [ABSTRACT FROM PUBLISHER]

In a career spanning more than 50 years, George Arthur Frederick Seber has made significant contributions in many areas of statistics as well as foundational work in capture-recapture modeling. Seber was born in 1938 in Australia to New Zealand parents and moved back to New Zealand where he completed almost all of his schooling. After graduating with bachelors and masters degrees from the University of Auckland, Seber studied for his Ph.D. at Manchester on a Commonwealth Scholarship. In his first year, he was supervised by John Darroch with David Silvey taking over supervision for the final 18 months of the degree. Seber's Ph.D. thesis was remarkably fruitful leading to three papers in Biometrika, two in the Annals of Mathematical Statistics and one in the Journal of the Royal Statistical Society B. The topics covered were broad mixing foundational work on linear model theory with capture-recapture problems. His solution to the multi-sample single recapture problem anticipated the general solution to the open population problem that Seber published in 1965 concurrent with the work of George Jolly. Seber has been a prolific writer of books including classical texts on the linear model and nonlinear regression. His comprehensive book The Estimation of Animal Abundance appeared in two editions. He has recently completed tour books and is working on a book on open population capture recapture. Seber took up an invited personal Chair in Biometrics at the University of Otago in 1971, and then the foundational Chair in Statistics at the University of Auckland in 1973. Seber developed a remarkable statistics group built around people such as Jeffrey Hunter, Alan Lee, Alastair Scott, Chris Triggs and Chris Wild, all of whom went on to hold Chairs in Statistics and to head Departments of Statistics in New Zealand. Seber was elected a Fellow of the Royal Society of New Zealand (RSNZ) in 1997 and in 1999 was awarded the Hector Medal by the RSNZ. [ABSTRACT FROM AUTHOR]

Richard Melville Cormack is one of the giants who developed the theory of mark-recapture. Referring to his key paper in 1964, and the papers published back-to-back in 1965 by George Jolly and George Seber, the "Cormack-Jolly-Seber model" is central to the development of markrecapture methods for estimating survival. Richard was bom on 12 March 1935. His father was Principal of Stow College of Engineering in Glasgow. From the age of 7, Richard attended Glasgow Academy, and later entered directly into the second year at King's College, Cambridge, intending at the time to be a theoretical astronomer. He secured first class honours in Special Mathematics from London as an external student in 1954, and second class honours in Mathematics from Cambridge in 1955. After changing direction, he left Cambridge in 1956 with a Distinction in the Diploma in Mathematical Statistics. Richard's PhD, undertaken while a lecturer at Aberdeen, was completed in 1961. Richard's period at Aberdeen (1956-1966) coincided with a golden era for statistics there, and his colleagues included D. J. Finney, Bill Brass, Peter Fisk, David M. G. Wishart, Michael Sampford, Robert Cumow, George Jolly and Andrew Rutherford (the last four being members of the ARC Unit of Statistics). In common with a number of these colleagues, he moved to Edinburgh in 1966, holding a Senior Lectureship there until 1972, when he became the first Professor of Statistics at St Andrews. Richard's groundbreaking contributions to mark-recapture in the early 1960s continued when he addressed the issue of heterogeneity in capture probabilities, publishing a test for heterogeneity in Biometrics in 1966. Then in 1972, in another Biometrics paper, he showed the logic behind capturerecapture estimates, making the methods more accessible and understandable to the user community. In 1981, jointly with Philip North, Richard published important insights into mark-recovery models. His work on log-linear models for mark-recapture led to papers in Biometrika in 1984 (with Ron Sandland) and 1991 (with Peter Jupp), and in Biometrics in 1989, and, additionally, to four book chapters. There was also a sequence of Biometrics capture-recapture papers in the 1990s: on modelling covariates (1990), on interval estimation (1992) and on variance estimation (1993). After retirement in 1994, his publications in mark-recapture were mostly as co-author in epidemiology studies. Richard also published on other diverse topics, often with scientists from other disciplines. His 1971 review of classification, read to the Research Committee of RSS and later appearing in JRSS A, is a classic, and while his 1988 exposition on statistical challenges in the environmental sciences (also in JRSS A) has had substantially less impact, it too showed his characteristic incisiveness. His contributions to a wide range of committees, working groups, visiting groups and scientific organisations (including council member for NERC and the Freshwater Biological Association) were substantial. He was elected a member of the IS1 in 1962 and a Fellow of the Royal Society of Edinburgh in 1974. He held various offices within the Biometric Society, as Secretary of the British Region 1970-1977, Regional President 1990-1992 and President of the International Society 1980-1981. He served on the Council and various committees of the Royal Statistical Society. Richard married Edith Whittaker on 1st September 1960, at King's College Chapel, Aberdeen. Edith is a plant ecologist, and a past chairperson of the Fife and Kinross Branch of the Scottish Wildlife Trust and of the Friends of St Andrews Botanic Garden; she was also a founding member of the Garden's Education Trust. Their son Andrew is a European Chartered Engineer working for the JANET network, while their daughter Anne is a Marketing Manager. Photography has been a passion of Richard's for many decades. He was a lecturer and judge for 40 years for the Scottish Photographic Federation, and was placed on their roll of honour. He has held exhibitions in Dundee (Land of the Berbers), St Andrews (Growth and Form) and Aberdeen (Walking in the North), and has given many talks. Richard firmly established the University of St Andrews as a centre for statistical ecology, a strength that continues today. [ABSTRACT FROM AUTHOR]

The amphibian chytrid fungus, Batrachochytrium dendrobatidis, is one of the main factors in global amphibian decline. Accurate knowledge of its presence and prevalence in an area is needed to trigger conservation actions. However, imperfect capture rates determine the number of individuals caught and tested during field surveys, and contribute to the uncertainty surrounding estimates of prevalence. Screening programs should be planned with the objective of minimizing such uncertainty. We show how this can be achieved by using predictive models that incorporate information about population size and capture rates. Using as a case study an existing screening program for three populations of the yellow-bellied toad (Bombina variegata pachypus) in northern Italy, we sought to quantify the effect of seasonal variation in individual capture rates on the uncertainty surrounding estimates of chytrid prevalence. We obtained estimates of population size and capture rates from mark-recapture data, and found wide seasonal variation in the individual recapture rates. We then incorporated this information in a binomial model to predict the estimates of prevalence that would be obtained by sampling at different times in the season, assuming no infected individuals were found. Sampling during the period of maximum capture probability was predicted to decrease upper 95% credible intervals by a maximum of 36%, compared with least suitable periods, with greater gains when using uninformative priors. We evaluated model predictions by comparing them with the results of screening surveys in 2012. The observed results closely matched the predicted figures for all populations, suggesting that this method can be reliably used to maximize the sampling size of surveillance programs, thus improving their efficiency. [ABSTRACT FROM AUTHOR]

When there are frequent capture occasions, both semiparametric and nonparametric estimators for the size of an open population have been proposed using kernel smoothing methods. While kernel smoothing methods are mathematically tractable, fitting them to data is computationally intensive. Here, we use smoothing splines in the form of P-splines to provide an alternate less computationally intensive method of fitting these models to capture–recapture data from open populations with frequent capture occasions. We fit the model to capture data collected over 64 occasions and model the population size as a function of time, seasonal effects and an environmental covariate. A small simulation study is also conducted to examine the performance of the estimators and their standard errors. [ABSTRACT FROM PUBLISHER]

Individual members of a population of 'prolonged' breeding amphibian species are asynchronously present at their breeding sites. Therefore, population size estimates can be misleading when based on commonly used closed or open-population capture-mark-recapture approaches. The superpopulation approach, a modified Jolly-Seber model, has been successfully applied in taxa other than amphibians with distinct migratory behaviour and where individuals are asynchronously present at the sampling site. In this paper, we suggest that the superpopulation approach is a useful population size estimator for 'prolonged' breeding amphibian species. Two case studies on European anurans show that superpopulation estimates are much higher than simple population counts. A simulation study showed that superpopulation estimates are unbiased but that accuracy can be low when either survival or detection probabilities (or both) are low. We recommend the superpopulation approach because it matches the natural history and phenology of amphibian species with prolonged breeding seasons. [ABSTRACT FROM AUTHOR]

We develop a hierarchical capture-recapture model for demographically open populations when auxiliary spatial information about location of capture is obtained. Such spatial capture-recapture data arise from studies based on camera trapping, DNA sampling, and other situations in which a spatial array of devices records encounters of unique individuals. We integrate an individual-based formulation of a Jolly-Seber type model with recently developed spatially explicit capture-recapture models to estimate density and demographic parameters for survival and recruitment. We adopt a Bayesian framework for inference under this model using the method of data augmentation which is implemented in the software program WinBUGS. The model was motivated by a camera trapping study of Pampas cats Leopardus colocolo from Argentina, which we present as an illustration of the model in this paper. We provide estimates of density and the first quantitative assessment of vital rates for the Pampas cat in the High Andes. The precision of these estimates is poor due likely to the sparse data, set. Unlike conventional inference methods which usually rely on asymptotic arguments, Bayesian inferences are valid in arbitrary sample sizes, and thus the method is ideal for the study of rare or endangered species for which small data sets are typical. [ABSTRACT FROM AUTHOR]

Crayfish are regarded as useful indicators of environmental quality and freshwater biodiversity. However, reliable methods for monitoring their populations are needed so that this potential can be fully utilised. We report and discuss methodological aspects of the white-clawed crayfish (Austropotamobius pallipes complex) survey conducted in Piedmont, Italy, with the use of mark-recapture. The results suggest that the method can serve as a convenient tool for estimating the size of crayfish populations and inferring their temporal trends. The two populations investigated appeared closed except for wintertime and July. Consequently, the Robust Design, which is regarded as the most reliable mark-recapture approach, can be easily applied. The minimum effective sampling plan for monitoring purposes should comprise one primary period per year, conducted in the summer¿autumn season, and consisting of three capture sessions. If gaining insight into the ecology of the investigated species is the prime objective and sufficient resources are available, the optimal plan should include two primary periods (in spring and the summer¿ autumn season) of five capture sessions each. Capture sessions need to be separated by roughly 2-week intervals in order to avoid the strong, but short-term, negative effect of capturing crayfish on their recapture chances. As the model without heterogeneity in capture probabilities ensures better estimate precision we recommend that data collected for both sexes are analysed separately. Taking into consideration higher male catchabilities and sex ratio being invariably 1:1, it also seems beneficial to estimate only male numbers and double them to achieve total population sizes. [ABSTRACT FROM AUTHOR]

We present a hierarchical extension of the Cormack–Jolly–Seber (CJS) model for open population capture–recapture data. In addition to recaptures of marked animals, we model first captures of animals and losses on capture. The parameter set includes capture probabilities, survival rates, and birth rates. The survival rates and birth rates are treated as a random sample from a bivariate distribution, thus the model explicitly incorporates correlation in these demographic rates. A key feature of the model is that the likelihood function, which includes a CJS model factor, is expressed entirely in terms of identifiable parameters; losses on capture can be factored out of the model. Since the computational complexity of classical likelihood methods is prohibitive, we use Markov chain Monte Carlo in a Bayesian analysis. We describe an efficient candidate-generation scheme for Metropolis–Hastings sampling of CJS models and extensions. The procedure is illustrated using mark-recapture data for the mothGonodontis bidentata. [ABSTRACT FROM AUTHOR]

The assumption of demographic closure in the analysis of capture-recapture data under closed-population models is of fundamental importance. Yet, little progress has been made in the development of omnibus tests of the closure assumption. We present a closure test for time-specific data that, in principle, tests the null hypothesis of closed-population model M against the open-population Jolly-Seber model as a specific alternative. This test is chi-square, and can be decomposed into informative components that can be interpreted to determine the nature of closure violations. The test is most sensitive to permanent emigration and least sensitive to temporary emigration, and is of intermediate sensitivity to permanent or temporary immigration. This test is a versatile tool for testing the assumption of demographic closure in the analysis of capture-recapture data. [ABSTRACT FROM AUTHOR]