Movement and habitat use of lake sturgeon (Acipenser fulvescens) in the South Saskatchewan River system

Abstract

Lake Sturgeon (Acipenser fulvescens) have experienced declines in numbers throughout their range due to historical overharvesting and more recent habitat degradation. Fragmentation and disruption caused by large dams on the rivers they inhabit have greatly impacted this species. Lake Sturgeon in Alberta are part of an Endangered population as defined by the Committee on the Status of Endangered Wildlife in Canada. The goal of this study was to gather more information on the movement of Lake Sturgeon in the South Saskatchewan River in Alberta and Saskatchewan, to aid conservation. A sample of 123 Lake Sturgeon was tracked in this area for 24.5 months using hydroacoustic telemetry, and a habitat survey gathered depth and substrate data for the study area. Lake Sturgeon had large ranges of movement, and individuals moved the second-highest range on record for this species. Movement varied by season, and adult Lake Sturgeon moved at higher rates and used greater reaches of the river than juveniles. Two possible spawning sites and three overwintering sites were identified, areas which should be left undisturbed by development. The large extent of movement observed in the study area emphasizes the need to leave the South Saskatchewan River system relatively unrestricted by dams and weirs, as blocking movement may have negative impacts on this population of Lake Sturgeon.