Acoustic telemetry data characterizes movement behaviors of yearling and sub-adult Lake Sturgeon (Acipenser fulvescens) within the Genesee River, NY

Abstract

In the Laurentian Great Lakes basin, Lake Sturgeon (Acipenser fulvescens) populations were decimated by the turn of the 20th century, but in some areas are beginning to rebound after decades of ongoing rehabilitation efforts. In the Genesee River of Lake Ontario, hatchery-raised Lake Sturgeon have been stocked in hopes of re-establishing a healthy and self-sustaining population. To understand the efficacy of these efforts and to build an understanding of how these stocked individuals use the Genesee River and Lake Ontario habitats, ninety-nine juvenile lake sturgeon (30 sub-adults, 69 yearlings) were tagged with acoustic transmitters and tracked for approximately two years. Water quality parameters were monitored with the combined use of a USGS stream gauge and passive dissolved oxygen monitors. A multi-state model created to estimate survival and transitions from the Genesee River to Lake Ontario revealed that sub-adults had higher survival rate compared to yearlings. Yearling survival estimates were higher than previously estimated with capture-mark-recapture techniques, likely a result of being able to account for emigration. Sub-adults used both lake and river habitats more than yearlings, although both life stages frequently utilized both habitats. Seven sub-adults made large scale migrations (>100km) to either the Lower Niagara River or the St. Lawrence River. Hypoxic conditions that relate to discharge formed during the summer months within the Genesee River and appeared to limit Lake Sturgeon movements. The use of and survival in the Genesee River indicates that stocked juvenile Lake Sturgeon are using it as a nursery habitat. This has important implications when considering the efficacy of this management approach with implications for supplementing population abundance, understanding habitat use, and directing management efforts. Patterns of large-scale movements and nearshore habitat use exhibited by sub-adults should continue to be monitored as they could prove to influence vital rates (i.e., survival, recruitment, growth) and inform the degree of connectivity among populations throughout the Lake Ontario basin.