Efficiency of electrofishing in turbid lowland rivers: implications for measuring temporal change in fish populations

Lyon, Jarod; Bird, Tomas J.; Nicol, Simon; Kearns, Joanne; O’Mahony, Justin; Todd, Charles R.; Cowx, I. G.; Bradshaw, Corey J. A.

doi:10.1139/cjfas-2013-0287

Cited by 63 publications

(77 citation statements)

References 27 publications

(30 reference statements)

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“…For instance, discharge directly and indirectly influences both fish behavior and sampling efficiency in lotic systems (Lyon et al. ; Gwinn et al. ).…”

Section: Discussionmentioning

confidence: 99%

Evaluation of Unbaited Hoop Nets for Simultaneously Assessing Channel Catfish and Flathead Catfish populations in the Minnesota River

Sindt

2018

N American J Fish Manag

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Fisheries managers desire efficient sampling methods with sufficient precision for monitoring ictalurid catfish populations. For this study, I conducted single unbaited hoop‐net surveys in the Minnesota River to evaluate the efficacy of simultaneously assessing stock‐size (≥280‐mm) Channel Catfish Ictalurus punctatus and quality‐size (≥510‐mm) Flathead Catfish Pylodictis olivaris populations. I compared catch rates and length‐frequency distributions among months (April–September) and used resampling procedures to estimate the number of hoop‐net samples needed to achieve desirable precision of catch rate estimates and adequate statistical power. Catch rates (mean ± SE) were 2.1 ± 0.3 fish/net‐night for Channel Catfish and 0.8 ± 0.1 fish/net‐night for Flathead Catfish. Resampling procedures demonstrated that desirable precision (i.e., relative SE ≤ 25) and adequate statistical power (≥0.80 with α = 0.10) to detect 50% reductions in mean catch rates with two‐tailed t‐tests could be achieved for both species with as few as 68 hoop‐net samples during August. Unbaited hoop nets are effective for simultaneously assessing Channel Catfish and Flathead Catfish populations in the Minnesota River, and conducting surveys during August provides the best balance between catch rate and precision while minimizing perceived environmental and behavioral biases. However, the amount of sampling effort needed to detect small population changes (<50%) and to collect sufficient sample sizes for age and growth analyses may be logistically prohibitive. This study emphasizes the importance of evaluating precision and statistical power of sampling methods so that fisheries managers can identify the most suitable methods for their specific objectives.

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“…For instance, discharge directly and indirectly influences both fish behavior and sampling efficiency in lotic systems (Lyon et al. ; Gwinn et al. ).…”

Section: Discussionmentioning

confidence: 99%

Evaluation of Unbaited Hoop Nets for Simultaneously Assessing Channel Catfish and Flathead Catfish populations in the Minnesota River

Sindt

2018

N American J Fish Manag

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“…; Bayley and Austen ; Reynolds and Kolz ; Lyon et al. ). Furthermore, conventional boat electrofishing has a bias toward large‐bodied fish and may overrepresent larger fish while underrepresenting smaller‐sized fish (Chick et al.…”

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confidence: 99%

A Comparison between Conventional Boat Electrofishing and the Electrified Dozer Trawl for Capturing Silver Carp in Tributaries of the Missouri River, Missouri

Hammen

Pherigo

Doyle

et al. 2019

N American J Fish Manag

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Silver Carp Hypophthalmichthys molitrix are elusive fish that can be difficult to capture with conventional management tools. New tools must be developed to help increase the capture of Silver Carp, thereby improving the understanding and management of the species. An electrified dozer trawl was developed in an attempt to increase the capture of Silver Carp while reducing the amount of sampling effort needed to successfully assess a population and inform management actions. We compared Silver Carp catch rates, sample run time, and Silver Carp length frequency distributions from the electrified dozer trawl with those from conventional boat electrofishing. Silver Carp capture was greater and sample time was shorter for the electrified dozer trawl compared to conventional boat electrofishing. Length frequency distributions were similar between gears. The electrified dozer trawl can shorten sample run times and potentially improve Silver Carp capture, thus facilitating management. Use of the electrified dozer trawl should be expanded beyond Missouri River tributaries to further understand the gear's potential for sampling Silver Carp in a diverse array of environments.

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“…Lower Green Bay is shallow (, 5 m), eutrophic to hypereutrophic, and highly turbid (Trebitz et al 2007;Althouse et al 2014) with water clarity often , 0.5 m. High turbidity is known to reduce visibility of electroshocked fish to netters, particularly small fishes and those lacking swim bladders (Reynolds 1996;Brousseau et al 2005;Price and Peterson 2010). Electrofishing capture efficiency in many systems, and for most species, is low and becomes poorer at extreme levels of turbidity (Reynolds 1996;Lyon et al 2014). Assuming low capture efficiency during marking runs, it is unlikely that we achieved depletion of abundance and diversity in the study area.…”

Section: Discussionmentioning

confidence: 99%

How Quickly Do Fish Communities Recover From Boat Electrofishing in Large Lakes?

Smith

Simpkins

Strakosh

2017

Journal of Fish and Wildlife Management

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For specific sampling questions researchers may need to target ideal habitats concurrently and collect reliable fish community data, but unfortunately, we know little about the recovery rate of fish communities in areas recently subjected to electrofishing. In small systems, electrofishing can quickly deplete a sample area but this effect is unlikely at larger spatial scales. We conducted an experiment to identify how quickly fish communities recover from electrofishing in Green Bay, an embayment of Lake Michigan. We conducted electrofishing at 31 sites that were randomly assigned to be resampled at 0.25, 1, 3, 6, 24, or 48 h postrelease of marked fish. We marked all fish ! 150 mm and released them at their capture site. We found no differences in catch per unit effort, mean total length, species richness, Shannon's diversity, or Shannon's evenness between marking and recapture runs for any length of recovery duration between electrofishing runs. We recaptured only one of 349 marked fish in the site where it was released. Recapture of five fish in areas outside where they were released was unrelated to recovery duration between electrofishing events. In large, open systems like Green Bay, we found that disturbances caused by electrofishing are temporary (, 15 min) and suspect that any fish removed are quickly replaced by new immigrants to the study area. Due to high turbidity in this eutrophic-hypereutrophic system, we suspect that electrofishing efficiency was low; therefore resampling had the potential benefit of collecting individuals missed during marking runs. We conclude that fish communities in large lakes recover quickly following electrofishing and sites can be sampled concurrently within the same day and provide similar, or additional, fish community information.

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Efficiency of electrofishing in turbid lowland rivers: implications for measuring temporal change in fish populations

Cited by 63 publications

References 27 publications

Evaluation of Unbaited Hoop Nets for Simultaneously Assessing Channel Catfish and Flathead Catfish populations in the Minnesota River

Evaluation of Unbaited Hoop Nets for Simultaneously Assessing Channel Catfish and Flathead Catfish populations in the Minnesota River

A Comparison between Conventional Boat Electrofishing and the Electrified Dozer Trawl for Capturing Silver Carp in Tributaries of the Missouri River, Missouri

How Quickly Do Fish Communities Recover From Boat Electrofishing in Large Lakes?

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