Interaction of sauger Sander canadensis and walleye Sander vitreus in a large, shallow northern river. Issue 3 (29th July 2019)

• Record Type: Journal Article
• Authors: Haxton, Tim; Friday, Mike
• Is Part Of: Journal of fish biology. Volume 95:Issue 3(2019)
• Page Start: 847
• Page End: 854
• Publication Date: 2019-07-29
• Subjects: large shallow river -- Sander canadensis -- Sander vitreus -- sympatric -- year‐class; Fishes -- Periodicals; Fishes -- Great Britain -- Periodicals; 597
• DOI: 10.1111/jfb.14080
• Languages: English
• ISSNs: 0022-1112

Abstract

Abstract: The objectives of this study were to: (1) determine the relative abundance of sauger Sander canadensis and walleye S. vitreus within the Rainy River using a standardized index netting technique; (2) assess the life‐history characteristics of the two species in a northern river; (3) examine the spatial distribution of the two species; (4) assess year‐class synchrony. At a larger scale, relative abundance of S. canadensis and S. vitreus were similar among sections of the river. However, at a finer scale, S. canadensis were the dominant species over more area (24%) of the river than S. vitreus (12%). Life‐history traits for both species were within the range reported for North American. Mortality rates were similar, suggesting that anglers were not affecting one species more than the other. Year‐class strengths were not synchronous between S. canadensis and S. vitreus ( r = 0.07). There was evidence of S. canadensis potentially outcompeting S. vitreus with a strong year class of S. canadensis followed by a very weak class of S. vitreus . Additionally, S. canadensis were larger than S. vitreus in most sections of the river when adjusted for mean size. However, the potential interspecific competition was not to the exclusion of S. vitreus . Turbidity was probably the factor that enable S. canadensis to survive sympatrically with S. vitreus given their inability to segregate by depth within the river.