Distance Sampling: Methods and Applications

Buckland, Stephen T.; Rexstad, Eric A.; Marques, Tiago A.; Oedekoven, C. S.

doi:10.1007/978-3-319-19219-2

Cited by 351 publications

(385 citation statements)

References 151 publications

(239 reference statements)

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“…Surveys were conducted at an altitude of 244 -305 m and 100 knots ground speed, primarily from a high-wing, twin-engine Partenavia P68 and glass-nosed Observer (n = 17 surveys), with the remaining survey made from an Aero Commander aircraft. Observation effort occurred throughout each flight focused along systematic transect lines following conventional distance sampling protocol (Buckland, Rexstad, Marques, & Oedekoven, 2015). Two observers searched for marine mammals on each side of the aircraft through a bubble window while a recorder collected data on a laptop running customized data collection and mapping software, including Mysticetus™ (www.mysticetus.com).…”

Section: Aerial Survey Protocolmentioning

confidence: 99%

Cetacean mother-calf behavior observed from a small aircraft off Southern California

Smultea¹,

Fertl²,

Bacon³

et al. 2017

AB&C

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Section: Aerial Survey Protocolmentioning

confidence: 99%

Cetacean mother-calf behavior observed from a small aircraft off Southern California

Smultea¹,

Fertl²,

Bacon³

et al. 2017

AB&C

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“…To model the detection function we considered the key function and series adjustment term combinations recommended by Buckland et al (2001, p.47; Tables 1 and 2). The model selected for inference was that with lowest Akaike information criterion (AIC, Burnham and Anderson 2002); goodness of fit of the selected model was evaluated using quantile-quantile plots, Kolmogorov-Smirnov, and Cramér-von Mises tests (Buckland et al 2015). In our analyses, the variance in the estimate of tortoise density resulted from the combination of three variance components: 1) encounter rate of burrows, 2) detectability of burrows, and 3) burrow occupancy by tortoises (see Text S1 for the relevant formulae).…”

Section: Discussionmentioning

confidence: 99%

“…Endangered Species Act [ESA] 1973, as amended;USFWS 1987USFWS , 2011. Line transect distance sampling (LTDS; Buckland et al 2001Buckland et al , 2015 has become a standard technique to estimate gopher tortoise abundance as it has proven to be an efficient method relative to plot-based totalcount surveys, or burrow counts with unverified occupancy conversion factors (Nomani et al 2008;Smith et al 2009;USFWS 2012). A key strength of distance sampling is that not all animals have to be detected; instead, observed distances to detections are used to fit a detection function, which describes how probability of detection declines with increasing distance from the transect line.…”

Section: Introductionmentioning

confidence: 99%

Techniques for Estimating the Size of Low-Density Gopher Tortoise Populations

Stober

Prieto-Gonzalez

Smith

et al. 2017

Journal of Fish and Wildlife Management

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Gopher tortoises (Gopherus polyphemus) are candidates for range-wide listing as threatened under the U.S. Endangered Species Act. Reliable population estimates are important to inform policy and management for recovery of the species. Line transect distance sampling has been adopted as the preferred method to estimate population size. However, when tortoise density is low, it can be challenging to obtain enough tortoise observations to reliably estimate the probability of detection, a vital component of the method. We suggest a modification to the method based on counting usable tortoise burrows (more abundant than tortoises) and separately accounting for the proportion of burrows occupied by tortoises. The increased sample size of burrows can outweigh the additional uncertainty induced by the need to account for the proportion of burrows occupied. We demonstrate the method using surveys conducted within a 13,118-ha portion of the Gopher Tortoise Habitat Management Unit at Fort Gordon Army Installation, Georgia. We used a systematic random design to obtain more precise estimates, using a newly developed systematic variance estimator. Individual transects had a spatially efficient design (pseudocircuits), which greatly improved sampling efficiency on this large site. Estimated burrow density was 0.091 6 0.011 burrows/ha (CV ¼ 12.6%, 95% CI ¼ 0.071-0.116), with 25% of burrows occupied by a tortoise (CV ¼ 14.4%), yielding a tortoise density of 0.023 6 0.004 tortoise/ha (CV ¼ 19.0%, 95% CI ¼ 0.016-0.033) and a population estimate of 297 tortoises (95% CI ¼ 210-433). These techniques are applicable to other studies and species. Surveying burrows or nests, rather than animals, can produce more reliable estimates when it leads to a significantly larger sample of detections and when the occupancy status can reliably be ascertained. Systematic line transect survey designs give better precision and are practical to implement and analyze.

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“…The final yearly trend was calculated from the delta lognormal distribution by area-weighting of management strata when the interaction term of year and area was significant (Lo et al 1992;Maunder and Punt 2004). The confidence intervals of relative abundance trends were approximately calculated assuming a lognormal distribution for relative abundances and using the variance estimates from the Hessian matrix (Buckland et al 2015). All analyses were conducted using the free statistical software R (R Core Team 2016).…”

Section: Application Of the New Methods To Arabesque Greenling Cpue Datamentioning

confidence: 99%

Target-based catch-per-unit-effort standardization in multispecies fisheries

Okamura

Morita

Funamoto

et al. 2018

Can. J. Fish. Aquat. Sci.

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Standardized catch per unit effort (CPUE) is a fundamental component of fishery stock assessment. In multispecies fisheries, catchability can differ depending on which species is being targeted, and so the yearly trend extracted from the standardized CPUE is likely to be biased. We have, therefore, developed a method for predicting the unobserved variable related to targeted species from among multispecies composition data using a mixture regression model for the transformed residuals. In contrast with traditional methods, the proposed method predicts the target variable in CPUE standardization without removing a subset of the data. Keeping the entire data set avoids information loss, and so CPUE standardization with the predicted target variable should yield an unbiased estimate of the yearly trend. Simple simulation tests demonstrate that our method outperforms traditional methods. We illustrate the use of our method by applying it to CPUE data on arabesque greenling (Pleurogrammus azonus) caught in multispecies trawl fisheries in Hokkaido, Japan.Résumé : La capture par unité d'effort (CPUE) normalisée est une composante fondamentale de l'évaluation des stocks de poissons. Dans les pêches plurispécifiques, la capturabilité peut varier selon l'espèce ciblée, de sorte que la tendance annuelle obtenue à partir de la CPUE normalisée est susceptible d'être biaisée. C'est pourquoi nous avons mis au point une méthode de prédiction de la variable non observée associée aux espèces ciblées à partir de données sur la composition spécifique en utilisant un modèle de régression de mélanges pour les résidus transformés. Contrairement aux méthodes traditionnelles, la méthode proposée prédit la variable cible dans la normalisation de la CPUE sans retirer un sous-ensemble des données. Le fait de conserver l'entièreté de l'ensemble de données évite une perte d'information, de sorte que la normalisation de la CPUE avec la variable cible prédite devrait produire une estimation non biaisée de la tendance annuelle. Des essais de simulation simples démontrent que notre méthode donne de meilleurs résultats que les méthodes traditionnelles. Nous illustrons l'utilisation de notre méthode en l'appliquant à des données de CPUE pour des maquereaux atkas (Pleurogrammus azonus) pris dans une pêche plurispécifique au chalut à Hokkaido (Japon). [Traduit par la Rédaction]

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Distance Sampling: Methods and Applications

Cited by 351 publications

References 151 publications

Cetacean mother-calf behavior observed from a small aircraft off Southern California

Cetacean mother-calf behavior observed from a small aircraft off Southern California

Techniques for Estimating the Size of Low-Density Gopher Tortoise Populations

Target-based catch-per-unit-effort standardization in multispecies fisheries

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