Bias and Loss of Precision Due to Tag Loss in Jolly–Seber Estimates for Mark–Recapture Experiments

1981 ◽  
Vol 38 (9) ◽  
pp. 1077-1095 ◽  
Author(s):  
A. N. Arnason ◽  
K. H. Mills
Keyword(s):  
Loss Rate ◽  
Full Model ◽  
Coregonus Clupeaformis ◽  
Lake Whitefish ◽  
Mark Recapture ◽  
Tag Retention ◽  
Tag Loss ◽  
Capture Recapture ◽  
Biased Estimates ◽  
Theoretical Analyses

A crucial, though often ignored, assumption of mark–recapture experiments is that animals do not lose their marks (tags). We present results of theoretical analyses of the effects of tag loss on estimates of population size ([Formula: see text]), survival ([Formula: see text]), births or new entries ([Formula: see text]), and on their standard errors (SE()), for the Jolly–Seber (full) model allowing birth and death. We show that[Formula: see text], SE([Formula: see text]) and SE([Formula: see text]) are not biased by tag loss, while [Formula: see text], [Formula: see text], and SE([Formula: see text]) are biased. A similar analysis for the Jolly–Seber (death-only) model where births are known not to occur shows that [Formula: see text], [Formula: see text], and SE([Formula: see text]) are strongly biased by tag loss while only SE([Formula: see text]) is unbiased. Moreover, for both models, tag loss causes a loss in precision in all estimates (i.e. an increase in the standard error of the estimate, leading to wider confidence intervals). Throughout the paper, we assume that tag loss is homogeneous among animals; that is, it is the same for all marked animals regardless of age, sex, or tag-retention time, although the rate per unit time may change over time (e.g. over years or seasons within years).We develop analytic formulae for both models that allow calculation of the expected bias and SE in an estimate at given tag loss rates in a population of given size, subject to specified sampling, survival, and birth rates. The analytic formulae are large sample approximations, but are shown, by simulations, to be adequate provided marked captures (mi) and subsequent recoveries (ri) are no lower than around 5.We discuss how these calculations can be used in practical situations to plan experiments that will yield adequately precise estimates and to determine whether corrections to compensate for tag loss are necessary. In general, corrections are unnecessary if bias is slight or precision is poor. Otherwise, they should be corrected. The biased estimates from the full model ([Formula: see text], SE([Formula: see text]), and [Formula: see text]) are correctable only if an estimate of tag-loss rate is available. The death-only model estimates can all be corrected to eliminate bias due to tag loss both with and without knowledge of the tag-loss, rate. Knowledge of the tag-loss rate will usually give higher precision of the corrected estimates over those corrected without knowing the tag-loss rate.The Robson–Regier method of estimating tag loss can be used in experiments with double tagging where one tag is a permanent batch mark and where all recaptured animals are removed. We extend this method to allow for the multiple mark–recapture case where recaptures may be returned to the population. An example of the methods of estimating tag loss and then correcting the death-only model estimates is presented for some lake whitefish (Coregonus clupeaformis) data. Without the corrections, the estimates for these data would have been in serious error. The example provides some evidence that the correction may work even when the tag loss is not homogeneous across all animals.Recommendations are presented for planning mark–recapture experiments to minimize the problems created by tag loss.Key words: marking methods, tag loss, bias of estimates, capture–recapture, Jolly–Seber estimates, population estimates, survival, mortality, lake whitefish

Assessing tag loss and survival probabilities in green turtles (Chelonia mydas) nesting in Malaysia

2017 ◽  
Vol 98 (4) ◽  
pp. 961-972 ◽  
Author(s):  
Hideaki Nishizawa ◽  
Juanita Joseph ◽  
Vicki Yii-Ching Chew ◽  
Hock-Chark Liew ◽  
Eng-Heng Chan
Keyword(s):  
Confidence Interval ◽  
Survival Probability ◽  
Loss Rate ◽  
Chelonia Mydas ◽  
Loss Probability ◽  
Population Status ◽  
Mark Recapture ◽  
Survival Probabilities ◽  
Green Turtles ◽  
Tag Loss

The loss of external tags is one of the biggest problems in mark-recapture research. An evaluation of tag loss is therefore required to improve tagging methodology, select appropriate tag types, and accurately estimate population status and dynamics. We estimated tag loss probability of double-tagged green turtles (Chelonia mydas) nesting at Redang Island, Malaysia (05°49′ N 103°00′ E), from 1993–2014. For both titanium and Inconel tags, we found a tag loss pattern with a high initial tag loss rate that decreased to an asymptote near a constant value above zero. The initial tag loss probability for titanium tags was higher than for Inconel tags, and titanium tags were lost earlier than Inconel tags in more individuals when both types of tags were attached. In addition, comparison of the tag loss probability of Inconel tags attached during the period when tagging staff changed every year to that when senior tagging staff were not changed, indicated that lack of consistency in tagging staff affected the application of at least one of two Inconel tags. Estimated tag loss probability was incorporated into a recapture model, and annual survival probability was estimated to be 0.893 (95% confidence interval: 0.857–0.921).

Evaluation of a Mark–Recapture Method for Estimating Mortality and Migration Rates of Stratified Populations

1991 ◽  
Vol 48 (2) ◽  
pp. 254-260 ◽  
Author(s):  
Robert M. Dorazio ◽  
Paul J. Rago
Keyword(s):  
Maximum Likelihood ◽  
Sockeye Salmon ◽  
Maximum Likelihood Estimates ◽  
Fishing Mortality ◽  
Mark Recapture ◽  
Sampling Variability ◽  
Migration Rates ◽  
Tag Loss ◽  
And Migration ◽  
Biased Estimates

We simulated mark–recapture experiments to evaluate a method for estimating fishing mortality and migration rates of populations stratified at release and recovery. When fish released in two or more strata were recovered from different recapture strata in nearly the same proportions, conditional recapture probabilities were estimated outside the [0, 1] interval. The maximum likelihood estimates tended to be biased and imprecise when the patterns of recaptures produced extremely "flat" likelihood surfaces. Absence of bias was not guaranteed, however, in experiments where recapture rates could be estimated within the [0, 1] interval. Inadequate numbers of tag releases and recoveries also produced biased estimates, although the bias was easily detected by the high sampling variability of the estimates. A stratified tag–recapture experiment with sockeye salmon (Oncorhynchus nerka) was used to demonstrate procedures for analyzing data that produce biased estimates of recapture probabilities. An estimator was derived to examine the sensitivity of recapture rate estimates to assumed differences in natural and tagging mortality, tag loss, and incomplete reporting of tag recoveries.

Detection of Handling Mortality and its Effects on Jolly–Seber Estimates for Mark–Recapture Experiments

1987 ◽  
Vol 44 (S1) ◽  
pp. s64-s73 ◽  
Author(s):  
A. N. Arnason ◽  
K. H. Mills
Keyword(s):  
Mortality Rate ◽  
Mortality Rates ◽  
Population Abundance ◽  
Coregonus Clupeaformis ◽  
Great Care ◽  
Lake Whitefish ◽  
Mark Recapture ◽  
Bias Corrections

Handling mortality occurs in mark–recapture experiments if animals handled and released in a given sample have a higher mortality rate than animals that were alive but not sampled. This violates the assumption of equal survival required for forming the Jolly–Seber estimates of population abundance, survival, and recruitment. We show that handling mortality can produce very large biases in these estimates, and we develop a test to detect it. We investigate the power of this test and find that quite large biases can be produced at handling mortality rates that are too low to be detected. We recommend methods to prevent handling mortality from occurring in fish sampling experiments and methods to reduce bias in the estimates. The test and the bias corrections are applied to mark–recapture data for a lake whitefish (Coregonus clupeaformis) population and to data from simulated mark–recapture experiments. Because of unavoidable inadequacies in the detection and reduction of bias due to handling effects, we strongly recommend that fisheries biologists take great care to prevent its occurrence.

Spatial and temporal dynamics of lake whitefish (Coregonus clupeaformis) health indicators: Linking individual-based indicators to a management-relevant endpoint

2010 ◽  
Vol 36 ◽  
pp. 121-134 ◽  
Author(s):  
Tyler Wagner ◽  
Michael L. Jones ◽  
Mark P. Ebener ◽  
Michael T. Arts ◽  
Travis O. Brenden ◽  
...  
Keyword(s):  
Temporal Dynamics ◽  
Health Indicators ◽  
Coregonus Clupeaformis ◽  
Lake Whitefish ◽  
Spatial And Temporal Dynamics

Development of the embryonic heat shock response and the impact of repeated thermal stress in early stage lake whitefish ( Coregonus clupeaformis ) embryos

2017 ◽  
Vol 69 ◽  
pp. 294-301 ◽  
Author(s):  
Lindy M. Whitehouse ◽  
Chance S. McDougall ◽  
Daniel I. Stefanovic ◽  
Douglas R. Boreham ◽  
Christopher M. Somers ◽  
...  
Keyword(s):  
Thermal Stress ◽  
Heat Shock ◽  
Heat Shock Response ◽  
Early Stage ◽  
Coregonus Clupeaformis ◽  
Lake Whitefish ◽  
Shock Response ◽  
The Impact

Fecundity Comparisons for Various Stocks of Lake Whitefish, Coregonus clupeaformis

1975 ◽  
Vol 32 (3) ◽  
pp. 404-407 ◽  
Author(s):  
M. C. Healey ◽  
C. W. Nicol
Keyword(s):  
Northwest Territories ◽  
Lake Erie ◽  
Fork Length ◽  
Nonlinear Relationship ◽  
Coregonus Clupeaformis ◽  
Lake Whitefish ◽  
Limited Data ◽  
Relative Fecundity ◽  
Great Slave Lake ◽  
The Relationship

We found no significant differences in slope or intercept for the regression of loge fecundity on loge fork length among samples of whitefish from four lakes near Yellowknife in the Northwest Territories. The equation describing the relationship between fecundity and fork length for these populations was:[Formula: see text]Five other populations for which length–fecundity relationships could be calculated had length exponents ranging from 3.20 to 4.38, suggesting a nonlinear relationship between weight and fecundity. Six of the nine populations as well as four others for which limited data were available all had similar relative fecundities. Fish from Buck Lake in Alberta and from Lake Erie had high relative fecundities while fish from Great Slave Lake had low relative fecundity.

Occurrence of the eyefluke, Diplostomum (Diplostomum) baeri bucculentum Dubois et Rausch, 1948, in salmonid fishes of northern British Columbia

1985 ◽  
Vol 63 (2) ◽  
pp. 396-399 ◽  
Author(s):  
Hilda Lei Ching
Keyword(s):  
Rainbow Trout ◽  
Chinook Salmon ◽  
Sockeye Salmon ◽  
Lake Trout ◽  
Infected Fish ◽  
Salmo Gairdneri ◽  
Coregonus Clupeaformis ◽  
Lake Whitefish ◽  
Dolly Varden Salvelinus Malma ◽  
Prosopium Williamsoni

As a result of experimental infections in chicks, diplostomula found in the retina of chinook salmon from the Nechako River were identified as Diplostomum (Diplostomum) baeri bucculentum. Eyeflukes in other salmonids were considered to be the same species based on similar measurements and site in the eyes. These eyeflukes varied in prevalence and mean intensity in seven salmonid species surveyed in nine localities in 1979–1981. The following fish were sampled: rainbow trout (Salmo gairdneri), 505; mountain whitefish (Prosopium williamsoni), 334; lake whitefish (Coregonus clupeaformis), 32; Dolly Varden (Salvelinus malma), 66; lake trout (S. namaycush), 13; kokanee or sockeye salmon (Oncorhynchus nerka), 323; and chinook salmon (O. tshawytscha), 164. Eyeflukes had prevalences ranging from 84 to 100% in six lakes, 64% in the river, 53% in one reservoir site, and a prevalence of 15% in the other reservoir site. Mountain and lake whitefishes had high mean intensities while kokanee had low mean intensities. Correlation of increased intensity with increased fish size was significant for 6 of 27 samples. Four samples of lake whitefish, mountain whitefish, rainbow trout, and chinook salmon showed significant asymmetry when numbers of diplostomula were compared between eyes. More of the heavily infected fish showed asymmetry than did the lightly infected fish.

Phenotypic Variation in the Lake Whitefish, Coregonus clupeaformis, Induced by Introduction into a New Environment

1974 ◽  
Vol 31 (1) ◽  
pp. 55-62 ◽  
Author(s):  
J. S. Loch
Keyword(s):  
Feeding Habits ◽  
Morphological Characters ◽  
Coregonus Clupeaformis ◽  
Lake Whitefish ◽  
Meristic Characters ◽  
Line Scale ◽  
Benthic Food ◽  
Glycerol 3 Phosphate Dehydrogenase ◽  
Gill Raker ◽  
Electrophoretic Phenotype

Adult lake whitefish (Coregonus clupeaformis) from Clearwater Lake and second generation adults of offspring from Clearwater whitefish transplanted to Lyons Lake were compared with respect to morphometric and meristic characters and isozymes of L-glycerol-3-phosphate dehydrogenase (GPDH). Feeding habits and abundance of pelagic and benthic foods were compared in the two lakes.Gill raker number, lateral line scale count, and interorbital width remained constant between parental and offspring populations. Gill raker length was the main character found to differ between the populations. This was found to be related to the percentage and type of benthic food eaten. Abrasion of the gill rakers is offered as an explanation for the differences in gill raker length. Differences were found in various other meristic and morphological characters, as well as in electrophoretic phenotype frequencies of isozymes of GPDH.

Changes in fish populations affected by the construction of the La Grande complex (Phase I), James Bay region, Quebec

1995 ◽  
Vol 73 (10) ◽  
pp. 1860-1877 ◽  
Author(s):  
Jean-Claude DesLandes ◽  
Sylvie Guénette ◽  
Yves Prairie ◽  
Réjean Fortin ◽  
Dominique Roy ◽  
...  
Keyword(s):  
Lake Trout ◽  
Salvelinus Namaycush ◽  
Coregonus Clupeaformis ◽  
Lake Whitefish ◽  
Time Intervals ◽  
Complex Phase ◽  
Coregonus Artedii ◽  
Secondary Productivity ◽  
Longnose Sucker ◽  
The Impact

Catches per unit of effort (CPUE) with experimental gill nets, recruitment, growth, and condition were monitored between 1977 and 1992 to evaluate the impact of impoundment on the main fish species of La Grande 2, Opinaca, and Caniapiscau reservoirs and the Boyd–Sakami diversion. CPUE and recruitment of northern pike (Esox lucius) and lake whitefish (Coregonus clupeaformis) increased markedly at most stations after impoundment and decreased at the end of the series. The lake whitefish and cisco (Coregonus artedii) showed their most striking rise in CPUE at two bay stations of La Grande 2 and Opinaca reservoirs. CPUE and recruitment of the longnose sucker (Catostomus catostomus), white sucker (Catostomus commersoni), and lake trout (Salvelinus namaycush) (Caniapiscau) showed a general decrease following impoundment. CPUE for the walleye (Stizostedion vitreum) also decreased at several stations; however, the two most southerly stations in La Grande 2 reservoir and the Boyd–Sakami station showed high CPUE during the series. Concentration–redistribution phenomena explain part of the observed variations in CPUE. Correlation analyses showed that walleyes and white suckers were attracted to the warmer, more turbid stations, and that the high primary and secondary productivity of bay stations attracted the coregonines. Growth and condition of the main species increased during variable time intervals after impoundment and decreased at the end of the series.

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