Are removal-based abundance models robust to fish behavior?

Poorten, Brett T. van; Barrett, Boyd; Walters, Carl J.; Ahrens, Robert

doi:10.1016/j.fishres.2017.06.010

Cited by 12 publications

(6 citation statements)

References 26 publications

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“…However, focus on these factors overlooks the role of error and bias in independent population estimates in clouding relations between eDNA concentrations and populations (Yates, Cristescu, et al, 2021). In particular, multi‐pass removal electrofishing, commonly used to estimate the abundance of stream fishes, may underestimate abundance due to a violation of the assumption of constant detectability across passes (Hedger et al, 2018; van Poorten et al, 2017). Robust correction factors to convert eDNA concentrations to abundance, and measurements of the error of the method, could be obtained by releasing known numbers of eels in closed natural waters and then, after an acclimatisation period, comparing measured eDNA concentrations to known population sizes (see Harris et al, 2016; Stewart et al, 2019).…”

Section: Discussionmentioning

confidence: 99%

Thirteen novel ideas and underutilised resources to support progress towards a range‐wide American eel stock assessment

Cairns

Benchetrit

Bernatchez

et al. 2022

Fisheries Management Eco

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A robust assessment of the American eel (Anguilla rostrata) stock, required to guide conservation efforts, is challenged by the species’ vast range, high variability in demographic parameters and data inadequacies. Novel ideas and underutilised resources that may assist both analytic assessments and spatially oriented modelling include (1) species and environmental databases; (2) mining of data from scattered sources; (3) infilling of data gaps by spatial analysis; (4) age estimation from measurements of DNA methylation; evaluation of eel abundance by (5) larval, (6) glass‐bottom boat, (7) net enclosure and (8) eDNA surveys; (9) accounting for dam‐induced habitat increases in eel watercourse modelling; (10) spatially oriented modelling with and without temporal components; (11) geographically nested modelling of glass eel recruitment; (12) spawner per recruit modelling and (13) life cycle modelling to examine larval allocation effects. Eel biologists are too few to gather the required assessment data across all of the species’ range. Public posting of electrofishing and eDNA metabarcoding data sets and the use of machine learning techniques to comprehensively inventory small dams will help meet some data needs. These approaches address only a small proportion of the assessment challenges that face American eels. Worldwide collaboration amongst Anguilla scientists is a key enabler of progress towards stock assessment goals.

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Section: Discussionmentioning

confidence: 99%

Thirteen novel ideas and underutilised resources to support progress towards a range‐wide American eel stock assessment

Cairns

Benchetrit

Bernatchez

et al. 2022

Fisheries Management Eco

View full text Add to dashboard Cite

show abstract

“…Capture probability has often been observed to decline with successive passes (Borgstrøm and Skaala, 1993), which may result in biased estimates. For example, a simulation study by van Poorten et al (2017) found that no single removal method performed robustly under conditions of non-constant capture probability, generally causing an underestimate of abundance due to vulnerable fish being captured earlier. Even when assumptions are not violated, removal estimates are only reliable if sufficient numbers of individual fish are present within the fished area - Riley and Fausch (1992) for example estimated that a minimum sample size of 30 individuals within the site was required.…”

Section: Introductionmentioning

confidence: 99%

Bias in estimates of electrofishing capture probability of juvenile Atlantic salmon

et al. 2018

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We evaluated the effect of the total number of passes used, and the application of block nets, on multi-pass electrofishing removal sampling for estimating juvenile Atlantic salmon (Salmo salar L.) abundance and body size distribution. Sites within selected salmon-bearing Norwegian rivers were enclosed by block nets and electrofished for multiple passes (range: 7-13), and capture probabilities and abundances were estimated using the Carle and Strub removal method. We examined for different body size classes: (1) bias in the estimated capture probability and abundance associated with the number of passes used; (2) the potential for bias to be minimized by the use of block nets; and (3) electrofishing-induced mortality. We found that the capture probability estimate was strongly dependent upon the number of passes used, tending to decline with successive pass, with the effect depending on size class. Thus, estimates made using the traditional three-pass approach would result in underestimates of abundance, and biased estimates of size distribution. Smaller juveniles were both more likely to impinge on the block nets and more likely to experience mortality than larger juveniles. Mortality was greatest when water temperature was high (> 18 o C). Our findings indicate that quantitative electrofishing for small juveniles may be unreliable, and that electrofishing at high temperatures should be avoided due to potential high mortality.

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“…Individual differences in catchability unrelated to a particular group membership are still possible, but [ 32 ] showed that unless these differences are great, their effect on the population estimate is small. [ 39 ] investigated the robustness of the removal model to varying behaviours exhibited by fish using simulation.…”

Section: Resultsmentioning

confidence: 99%

Removal modelling in ecology: A systematic review

Rivera

McCrea

2021

PLoS ONE

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Removal models were proposed over 80 years ago as a tool to estimate unknown population size. More recently, they are used as an effective tool for management actions for the control of non desirable species, or for the evaluation of translocation management actions. Although the models have evolved over time, in essence, the protocol for data collection has remained similar: at each sampling occasion attempts are made to capture and remove individuals from the study area. Within this paper we review the literature of removal modelling and highlight the methodological developments for the analysis of removal data, in order to provide a unified resource for ecologists wishing to implement these approaches. Models for removal data have developed to better accommodate important features of the data and we discuss the shift in the required assumptions for the implementation of the models. The relative simplicity of this type of data and associated models mean that the method remains attractive and we discuss the potential future role of this technique.

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Are removal-based abundance models robust to fish behavior?

Cited by 12 publications

References 26 publications

Thirteen novel ideas and underutilised resources to support progress towards a range‐wide American eel stock assessment

Thirteen novel ideas and underutilised resources to support progress towards a range‐wide American eel stock assessment

Bias in estimates of electrofishing capture probability of juvenile Atlantic salmon

Removal modelling in ecology: A systematic review

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