Quantifying Seining Detection Probability for Fishes of Great Plains Sand‐Bed Rivers

Abstract

Species detection error (i.e., imperfect and variable detection probability) is an essential consideration when investigators map distributions and interpret habitat associations. When fish detection error that is due to highly variable instream environments needs to be addressed, sand‐bed streams of the Great Plains represent a unique challenge. We quantified seining detection probability for diminutive Great Plains fishes across a range of sampling conditions in two sand‐bed rivers in Oklahoma. Imperfect detection resulted in underestimates of species occurrence using naïve estimates, particularly for less common fishes. Seining detection probability also varied among fishes and across sampling conditions. We observed a quadratic relationship between water depth and detection probability, in which the exact nature of the relationship was species‐specific and dependent on water clarity. Similarly, the direction of the relationship between water clarity and detection probability was species‐specific and dependent on differences in water depth. The relationship between water temperature and detection probability was also species dependent, where both the magnitude and direction of the relationship varied among fishes. We showed how ignoring detection error confounded an underlying relationship between species occurrence and water depth. Despite imperfect and heterogeneous detection, our results support that determining species absence can be accomplished with two to six spatially replicated seine hauls per 200‐m reach under average sampling conditions; however, required effort would be higher under certain conditions. Detection probability was low for the Arkansas River Shiner Notropis girardi, which is federally listed as threatened, and more than 10 seine hauls per 200‐m reach would be required to assess presence across sampling conditions. Our model allows scientists to estimate sampling effort to confidently assess species occurrence, which maximizes the use of available resources. Increased implementation of approaches that consider detection error promote ecological advancements and conservation and management decisions that are better informed.

Effects of seining effort and site length on variability of small‐bodied fish catch‐rates in a sand‐bed river

“…Unequal or insufficient effort within sites may explain some of the ranges in detection probability reported in recent fisheries studies. A study examining detection probability of Great Plains minnows in two Oklahoma rivers reported relatively low detection probability of Arkansas River shiner Notropis girardi based on four seine hauls per 200 m site, and suggested >10 hauls were required to mitigate detection bias (Mollenhauer et al, 2018). In the Pecos River of New Mexico, single‐pass seining produced a poor representation of the fish assemblage, failing to detect many species that were present at all sites during depletion sampling (Widmer et al, 2010).…”

“…For seining, there is little information available on the effects of within‐site effort on catch‐rates and assemblage metrics. We recommend 2.5 times the within‐site effort used by Mollenhauer et al (2018) as the minimum effort in order to reduce the amount of variability in catch due to under sampling within a site. We suggest that four hauls per 200 m reach was too few, whereas 40 was too many.…”

“…Seines may also be the gear of choice when boat‐deployed gears are not practical, when electrofishing injury of sensitive or imperiled species is of concern (Dolan & Miranda, 2004), or when water quality conditions decrease the efficiency of electrofishing (Kolz, 2006). Seines are most effective in habitats with little habitat complexity, higher turbidity, lower velocity, and depths between 0.2 and 0.4 m (Mollenhauer, Logue, & Brewer, 2018). In larger wadeable rivers and streams, seines rarely cover the entire wetted width, and multiple, replicate hauls are often used within distinct mesohabitats (Rabeni, Lyons, Mercado‐Silva, & Peterson, 2009).…”

“…Many species of small‐bodied fishes of the Great Plains in the western United States are surveyed with seines (Mollenhauer et al, 2018; Perkin et al, 2019). These species have received increasing attention due to apparent declines in distribution and abundance over the past decades, due to fragmentation (Dudley & Platania, 2007; Perkin et al, 2015), alteration to flow regimes (Perkin et al, 2019), channel drying (Archdeacon, 2016), and changes to habitat (Hoagstrom, 2015).…”

Dispersal drives changes in fish community abundance in intermittent stream networks

“…Habitat measurements were taken following each fish sampling bout. Given that sampling efficiency can differ based on species and environmental conditions (Gwinn, Beesley, Close, Gawne, & Davies, ; Mollenhauer, Logue, & Brewer, ), we examined how pool and riffle depths differed across sampling events to ensure sampling efficiency did not confound results. Because sampling only occurred during base‐flow conditions, we found that mean pool and riffle depths were relatively constant at these sites (Figure S1) with mean depths typically within 0.1 m in pools and 0.05 m in riffles for most of the sampling events, never differing more than 0.5 m across sampling events.…”