Fixed versus Random Sampling of Fishes in a Large Reservoir

King, Terry; Williams, J. F.; Davies, William D.; Shelton, William L.

doi:10.1577/1548-8659(1981)110<563:fvrsof>2.0.co;2

Cited by 18 publications

(12 citation statements)

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“…One method to increase the ability to detect changes in CPUE is to adopt a fixed-site sampling design. A fixed-site sampling design can provide a more sensitive measure of temporal variation, but comparing estimates to other systems can be difficult (King et al 1981;Fourqurean et al 2003;Brown et al 2004). In contrast, randomly selected sites may better capture spatial variation, but spatial heterogeneity can obscure temporal trends (Fourqurean et al 2003;Brown et al 2004).…”

Section: Discussionmentioning

confidence: 99%

Random versus Fixed‐Site Sampling When Monitoring Relative Abundance of Fishes in Headwater Streams of the Upper Colorado River Basin

Quist

Gerow

Bower

et al. 2006

N American J Fish Manag

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Native fishes of the upper Colorado River basin (UCRB) have declined in distribution and abundance due to habitat degradation and interactions with nonnative fishes. Consequently, monitoring populations of both native and nonnative fishes is important for conservation of native species. We used data collected from Muddy Creek, Wyoming (2003–2004), to compare sample size estimates using a random and a fixed‐site sampling design to monitor changes in catch per unit effort (CPUE) of native bluehead suckers Catostomus discobolus, flannelmouth suckers C. latipinnis, roundtail chub Gila robusta, and speckled dace Rhinichthys osculus, as well as nonnative creek chub Semotilus atromaculatus and white suckers C. commersonii. When one‐pass backpack electrofishing was used, detection of 10% or 25% changes in CPUE (fish/100 m) at 60% statistical power required 50–1,000 randomly sampled reaches among species regardless of sampling design. However, use of a fixed‐site sampling design with 25–50 reaches greatly enhanced the ability to detect changes in CPUE. The addition of seining did not appreciably reduce required effort. When detection of 25–50% changes in CPUE of native and nonnative fishes is acceptable, we recommend establishment of 25–50 fixed reaches sampled by one‐pass electrofishing in Muddy Creek. Because Muddy Creek has habitat and fish assemblages characteristic of other headwater streams in the UCRB, our results are likely to apply to many other streams in the basin.

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Section: Discussionmentioning

confidence: 99%

Random versus Fixed‐Site Sampling When Monitoring Relative Abundance of Fishes in Headwater Streams of the Upper Colorado River Basin

Quist

Gerow

Bower

et al. 2006

N American J Fish Manag

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“…Despite the change in sampling regime, collections were made during the same three 45-d periods with the same electrofishing equipment and collection method. King et al (1981) found that variability in fish population parameters was comparable in samples collected from fixed versus random sites. We used data from both fixed-site sampling (1990,1991,1992) and from random sampling (1993,1994,1995) to assess size distributions of largemouth bass and also calculated an annual catch-per-unit-effort (CPUE) estimate.…”

Section: Methodsmentioning

confidence: 99%

Notes: Largemouth Bass Size Distributions under Varying Annual Hydrological Regimes in the Illinois River

Raibley¹,

O'Hara²,

Irons³

et al. 1997

Transactions of the American Fisheries Society

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Little is known about the population dynamics of largemouth bass Micropterus salmoides in temperate large river–floodplain ecosystems. However, the hydrological regimes in these systems are often similar to those of large reservoirs where fluctuating water levels during spawning have been shown to affect largemouth bass population dynamics. Most backwater lakes of the Illinois River have soft, silty substrates. These substrates are not conducive to nest building, so spawning centrarchids may use annual spring floods to access inundated terrestrial vegetation and previously dry, compacted substrates on the floodplain. We used electrofishing catch data from La Grange Reach of the Illinois River (1990–1995) to assess how spring and early‐summer river levels influence the cohort strength of largemouth bass. Strong cohorts were produced during years with high spring floods (1990, 1993, and 1995) when largemouth bass could access the floodplain for spawning and nursery habitat. In both 1990 and 1993, fish had access to the floodplain for extended periods during spring and summer, which resulted in exceptionally strong cohorts. These cohorts probably benefitted from abundant forage and cover on the floodplain, which bolstered survival rates. Weak cohorts were produced in 1992 and 1994 when river levels were low and fluctuating during spawning and in 1991 when river levels declined dramatically during spawning. Length distributions of other centrarchids mirrored those of largemouth bass, indicating that river levels probably affected other nest‐building species in La Grange Reach.

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“…Urquhart and Kincaid (1999) assessed power in various sampling designs that used both fixed and random plots, such as designs with random site revisits, and discussed the advantages of various sampling design strategies. Other studies comparing fixed and random sites in aquatic ecosystems have found either no difference in variation between fixed and random sites (King et al 1981), or lower variability for fixed sites (Van der Meer 1997). In our study, although fixed plots had 24% less variation than random plots, the difference in power between fixed and random site designs was small.…”

Section: Discussionmentioning

confidence: 98%

Using variance components to estimate power in a hierarchically nested sampling design

Dzul

Dixon

Quist

et al. 2012

Environ Monit Assess

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We used variance components to assess allocation of sampling effort in a hierarchically nested sampling design for ongoing monitoring of early life history stages of the federally endangered Devils Hole pupfish (DHP) (Cyprinodon diabolis). Sampling design for larval DHP included surveys (5 days each spring 2007-2009), events, and plots. Each survey was comprised of three counting events, where DHP larvae on nine plots were counted plot by plot. Statistical analysis of larval abundance included three components: (1) evaluation of power from various sample size combinations, (2) comparison of power in fixed and random plot designs, and (3) assessment of yearly differences in the power of the survey. Results indicated that increasing the sample size at the lowest level of sampling represented the most realistic option to increase the survey's power, fixed plot designs had greater power than random plot designs, and the power of the larval survey varied by year. This study provides an example of how monitoring efforts may benefit from coupling variance components estimation with power analysis to assess sampling design. Abstract We used variance components to assess allocation of sampling effort in a hierarchically nested sampling design for ongoing monitoring of early life history stages of the federally endangered Devils Hole pupfish (DHP) (Cyprinodon diabolis). Sampling design for larval DHP included surveys (5 days each spring 2007-2009), events, and plots. Each survey was comprised of three counting events, where DHP larvae on nine plots were counted plot by plot. Statistical analysis of larval abundance included three components:(1) evaluation of power from various sample size combinations, (2) comparison of power in fixed and random plot designs, and (3) assessment of yearly differences in the power of the survey. Results indicated that increasing the sample size at the lowest level of sampling represented the most realistic option to increase the survey's power, fixed plot designs had greater power than random plot designs, and the power of the larval survey varied by year. This study provides an example of how monitoring efforts may benefit from coupling variance components estimation with power analysis to assess sampling design.

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Fixed versus Random Sampling of Fishes in a Large Reservoir

Cited by 18 publications

References 0 publications

Random versus Fixed‐Site Sampling When Monitoring Relative Abundance of Fishes in Headwater Streams of the Upper Colorado River Basin

Random versus Fixed‐Site Sampling When Monitoring Relative Abundance of Fishes in Headwater Streams of the Upper Colorado River Basin

Notes: Largemouth Bass Size Distributions under Varying Annual Hydrological Regimes in the Illinois River

Using variance components to estimate power in a hierarchically nested sampling design

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