line transect
Methods for estimating sperm whale abundance from passive acoustic line transect surveys
... An alternative is to use ˆ N obs only to estimate mean school size, and to use conventional line transect methods on schools to estimate school abundance. If schools are readily identifiable (using some ...
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Double observer line transect surveys with Markov modulated Poisson process models for animal availability
... for line transect surveys in which animals go undetected at distance zero, either because they are stochastically unavailable while within view or because they are missed when they are avail- ...the ...
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Kernel Estimation in Line Transect Sampling for Parametric Model
... is line transect sampling. In line transect sampling technique, the density (𝐷) of the objects on interested area depends on the measured distances between the detected objects and the ...
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Global analysis of cetacean line transect surveys : detecting trends in cetacean density
... of line- transect survey records to determine whether temporal trends could be detected when survey effort from around the world was ...systematic line-transect surveys affect estimates of ...
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Review of potential line transect methodologies for estimating abundance of dolphin stocks in the eastern tropical Pacific
... on transect methods for fishery- independent data, however, there are other options for abundance estimation, including mark-recapture ...ship-based line- transect surveys (once research and ...
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Methods for investigating measurement error in cetacean line transect surveys
... Line-transect estimates of abundance generally assume that distances and angles to animals are measured without error. Biased distance measurements will lead to corresponding bias in abundance estimates. ...
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Designing a shipboard line transect survey to estimate cetacean abundance off the Azores Archipelago, Portugal
... Line transect surveys are commonly applied to wildlife populations or natural resources, as they provide a cost efficient manner of dealing with mobile populations that may be sparse over a large region ...
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An Adaptation of Kernel Density Estimation for Population Abundance using Line Transect Sampling When the Shoulder Condition is Violated
... Line transect technique is an easy approach that is used in practice to estimate population abundance, D , in line transect ...the line transect sampling is distributed as ...
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Accommodating availability bias on line transect surveys using hidden Markov models
... on line transect surveys. Line transect methods are well developed for situations in which animals are detected with certainty at zero ...recapture line transect (MRLT) methods ...
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Line transect sampling of primates : can animal to observer distance methods work?
... All of the above comparisons are based on studies where true density is established by studying a small number of habituated groups, and estimating the size of their home range. There are several reasons why there might ...
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Assessing the effects of measurement errors in line transect sampling
... A simulation study was carried out in which known amount of measurement error can be added to error-free line transect data (i.e. true perpendicular distances) to determine the effects o[r] ...
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Line-transect distance sampling compared with fixed-width strip-transect counts for assessing tomtit (Petroica macrocephala) population trends
... found line-transect distance sampling produced unbiased estimates of density, but point-count distance sampling did not (Cassey et ...In line-transect distance sampling, the peak of saddleback ...
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Design and analysis of line transect surveys for primates
... the line transect ...the line transect ...the line transect survey; variation in size and spread by time of day, season or other factors (Plumptre, 2000) will be controlled ...
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The effect of animal movement on line transect estimates of abundance
... strip transect sampling as- sumes a linear movement of animals, which is unrealistic and causes greater bias compared to other movement types ...the line transect simulation study we have not ...
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Double observer line transect methods : levels of independence
... In line transect sampling, an observer travels along each of a number of lines, laid out according to some randomised (usually systematic random) scheme, and records each detected animal, together with its ...
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State space approach to evaluate spatial variability of field measured soil water status along a line transect in a volcanic vesuvian soil
... Abstract. Unsaturated hydraulic properties and their spatial variability today are analyzed in order to use properly math- ematical models developed to simulate flow of the water and solute movement at the field-scale ...
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Size bias in line transect sampling: A field test
... In Figure 1 the estimated probability of sighting is plotted against perpendicular distance for transect 1 for each group size separatelY'.. 2.2 The Bxponential Power Sighting Function.[r] ...
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Modeling distribution and abundance of Antarctic baleen whales using ships of opportunity
... design-unbiased line transect surveys may be simply out of reach for researchers in many countries, which nonetheless grapple with problems of conservation of endangered species, by-catch of small cetaceans ...
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Extinction is imminent for Mexico’s endemic porpoise unless fishery bycatch is eliminated
... Our visual survey (28 September–4 December 2015) covered the entire range of vaquitas (Figure 1) in waters between 20- and 50-m deep. We used the same 52-m ship and visual line-transect survey methods used ...
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Distance sampling detection functions : 2D or not 2D?
... 2D line transect estimator can be seen as kind of removal method estimator, and that removal methods do not work well unless a large fraction of the population is removed, we believe these methods should be ...
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