Habitat preferences of young-of-year spotted gar (Lepisosteus oculatus) in Rondeau Bay, Lake Erie

Abstract

The young-of-year (YOY) habitat of many fishes listed under the Species at Risk Act (SARA) is poorly described, yet identifying critical habitat is essential to ensure species recovery. Past research on the Endangered Spotted Gar (Lepisosteus oculatus, (Winchell 1864)) in Canada has focused on the habitat use of adults and juveniles, but little is known about the occurrence and habitat use of YOY. Dip net and aquatic habitat sampling were performed in nearshore (lakefront, agricultural drain), mid-channel (agricultural drain), and offshore sites within Rondeau Bay to determine the fine-scale habitat occupancy patterns of age-0 Spotted Gar. Habitat preference analysis indicated YOY Spotted Gar strongly preferred shallow (0.5 – 1.0 m), vegetated, nearshore (lakefront and agricultural drain) habitat and avoided offshore habitat. An association between submerged aquatic vegetation (SAV) and fish size was also found, as dependence on SAV diminished as total length increased. Our study represents the first capture and assessment of habitat associations of early-stage YOY Spotted Gar in Canada. Given our findings, management efforts should focus on protecting the vegetated nearshore habitat in Rondeau Bay and other occupied locations in Lake Erie to ensure the long-term persistence of Spotted Gar in Canada.

Spotty distributions: Spotted Gar (Lepisosteus oculatus) and Spotted Sucker (Minytrema melanops) range expansion in eastern Lake Erie

“…Both of these fishes are widespread throughout the southern and central United States (Page and Burr, 2011) but are sporadically distributed in the Great Lakes basin (Boothroyd et al, 2016;Cudmore-Vokey and Crossman, 2000;George et al, 2022a;Hubbs and Lagler, 2004;Trautman, 1981). Lepisosteus oculatus is a large (up to 80 cm) top-level piscivorous predator preferring clear vegetated waters, particularly in wetlands and floodplain habitat of lakes and large rivers (Hubbs and Lagler, 2004;Page and Burr, 2011;Snedden et al, 1999;Suttkus, 1963;Trautman, 1981;Walker et al, 2013), while young-of-year individuals prefer low turbidity, shallow, vegetated nearshore habitat (McAllister et al, 2022). Adult L. oculatus have substantial dispersal capabilities, with reports of movement speeds up to 40.1 m/h (Snedden et al, 1999).…”