Evaluation and Comparison of a Habitat Suitability Model for Postdrift Larval Lake Sturgeon in the St. Clair and Detroit Rivers

Abstract

We evaluated composition and spatial distribution of riverine nursery habitat for larval Lake Sturgeon Acipenser fulvescens in the Middle Channel of the St. Clair River, Michigan, and Fighting Island Channel of the Detroit River, Ontario, using a habitat suitability model (HSM) and fish collections. Although model outputs indicated similar portions of high‐quality habitat in the Middle Channel (16.9%) and Fighting Island Channel (15.7%), larval abundance and dispersal patterns varied between these systems. Analysis with Akaike's information criterion indicated that a regression model using sand–silt substrate performed best at predicting the observed water‐volume‐standardized CPUE (number of larvae·h−1·m−3) in the Middle Channel. Of 93 larvae that were collected in the Middle Channel, most were found to cluster at three distinct areas of high‐ and moderate‐quality habitat, which was composed predominately of sand–silt substrate. Lengths of larvae varied by as much as 9 mm, and the degree of yolk sac absorption also varied, indicating that larvae in the Middle Channel remained within the channel after a short drift downstream. Of the 25 larvae that were collected in Fighting Island Channel, distribution was sporadic, and occurrence did not significantly correlate with measured habitat variables. Larvae were relatively homogeneous in size and yolk sac stage, indicating that newly emerged larvae did not utilize available habitat in Fighting Island Channel but instead drifted into the main channel of the Detroit River. Dispersal patterns indicate variability in young Lake Sturgeon ecology, which is dependent on local habitat conditions—most notably, substrate composition. Furthermore, modeled larval–habitat associations found in this study were compared to a similar study on larval Lake Sturgeon from the North Channel of the St. Clair River. Model outputs from all three systems accurately accounted for observed larval dispersal patterns among both rivers. This supports the transferability of an HSM parameterized for Lake Sturgeon from individual river reaches within two large river systems.

Identifying and characterizing juvenile lake sturgeon ( Acipenser fulvescens , Rafinesque, 1817) occupancy hot spots within the St. Clair‐Detroit River System

“…The juvenile lake sturgeon ‘hot spots’ identified were downstream of known lake sturgeon spawning locations, including constructed spawning reefs (Manny & Kennedy, 2002; Manny et al, 2015), which suggests connectivity between spawning and nursery areas in the St. Clair and Detroit rivers and could explain the spatial extent of ‘hot spots’. Krieger and Diana (2017) and Krieger et al (2018) found larval lake sturgeon in nursery habitat in the St. Clair and Detroit rivers close to spawning locations with catch rates diminishing with distance downstream. Barth et al (2011) also found that juvenile lake sturgeon in the Winnipeg River (50.1471 N, −95.8235 W) exhibit high natal site fidelity.…”

“…ery areas in the St. Clair and Detroit rivers and could explain the spatial extent of 'hot spots' Krieger and Diana (2017). andKrieger et al (2018) found larval lake sturgeon in nursery habitat in the St. Clair and Detroit rivers close to spawning locations with catch rates diminishing with distance downstream Barth et al (2011). also found that juvenile lake sturgeon in the Winnipeg River (50.1471 N, −95.8235 W) exhibit high natal site fidelity.…”

“…Juvenile lake sturgeon were sampled between March and December in the St. Clair River (1996-2018), Detroit River (2003-2018, and western Lake Erie (2013-2018) using gillnets and baited setlines.…”

“…Effective recovery efforts for threatened and endangered species requires an understanding of the type, quantity, and location of habitat used during various life stages to protect these areas and assess if habitat is limiting (Auer, 1996; Bruch et al, 2016; Rochard et al, 1990). Even though lake sturgeon ( Acipenser fulvescens ) population estimates are <1% of historic levels (Bauman et al, 2011; Briggs et al, 2020; Tody, 1974; Withers et al, 2019), little has been done to locate and quantify juvenile lake sturgeon habitat (Boase et al, 2014; Krieger et al, 2018). Juvenile lake sturgeon habitat has been described in other river systems but those conclusions may not be transferrable to river systems such as the Great Lakes connecting channels.…”

Larval lake sturgeon production and drift behaviour in the Menominee and Oconto Rivers, Wisconsin

“…predation or starvation) while drifting downstream from spawning grounds (Waraniak, Baker, & Scribner, 2018). Larval dispersal and postdrift settlement studies have led to the identification of downstream river habitats that may increase growth and survival (Krieger, Young, & Diana, 2018).…”