Quantification of Walleye Spawning Substrate in a Northern Minnesota River using Side‐Scan Sonar

Abstract

Evaluating aquatic habitats is an important component of many ecological studies and natural resource assessments, but traditional habitat evaluations are time and labor intensive and do not provide continuous data. Side‐scan sonar (SSS) can provide a low‐cost method that collects continuous aquatic habitat data. We used SSS mapping to quantify suitable spawning substrate available to Walleye Sander vitreus during the 2015 spring spawning migration in a 10.8‐km reach of the Tamarac River, Minnesota. The SSS map had 78.0% agreement with reference points classified in the field, and the proportion of reference points predicted as suitable using the SSS map was not significantly different than the proportion of reference points observed to be suitable. Suitable substrate for Walleye spawning comprised 8.4% (26,392 m2) of the total area mapped. The estimated number of females that suitable substrate could support was lower than the number that likely migrate up the Tamarac River and suggests that access to spawning substrate may sometimes limit reproductive success. This study demonstrates that a relatively inexpensive SSS unit can be used to efficiently map aquatic habitat while acquiring quantitative and qualitative data. Received July 6, 2016; accepted November 5, 2016 Published online March 10, 2017

Relationships among side‐scan sonar classified substrates and fish‐catch rates at multiple spatial scales

“…Side‐scan sonar surveys have been used extensively to study river systems to estimate the abundance of large fish (Flowers & Hightower, 2013) and mammalian species (Gonzalez‐Socoloske & Olivera‐Gomez, 2012), identify specific habitat types (Graham, Hafs, & Kennedy, 2017; Kaeser & Litts, 2008), classify large areas of substrate (Anima, Wong, Hogg, & Galanis, 2007; Kaeser et al, 2013), and assess habitat partitioning (Goclowski, Kaeser, & Sammons, 2013). In this study, we used side‐scan sonar substrate data to address two questions: how does the ability of substrate to explain differences in fish distribution within rivers vary among species?…”

Alluvial substrate mapping by automated texture segmentation of recreational-grade side scan sonar imagery

“…Kaeser et al [ 23 ] demonstrated that recreational-grade side scan sonar imagery, called echograms, collected using a recreational-grade system in a riverine environment had sufficient detail to map locations of large woody debris. Subsequent studies have established that the resolution and quality of the echogram is sufficient to visually identify sediment facies [ 19 – 21 ] over reaches up to hundreds of kilometers in length, and these sonar have enjoyed a proliferation of use among aquatic ecologists [ 19 – 21 , 23 – 30 ].…”

Using GIS to predict habitat in lakes: An example using nearshore substrate categories

“…The cost of units has decreased, methods have been developed and tested across systems, data can be collected continuously, and the process is faster than transect‐based methods (Kaeser and Litts ; Kaeser et al ; Richter et al ; Graham et al ). However, it still requires data collection in the field, postprocessing expertise, and field validation (Kaeser and Litts ; Graham et al ). Furthermore, neither of these methods directly associates the spatial locations of habitats to environmental factors that may be structuring their distributions.…”