Assessment of white sturgeon recruitment in John Day reservoir
September 2022 - August 2024
The construction of dams on the Columbia River has fragmented Pacific White Sturgeon (Acipenser transmontanus) habitats, producing essentially isolated populations between mainstem impoundments. Observations of young-of-the-year (YOY) White Sturgeon in the lower three Columbia River reservoirs (Bonneville, The Dalles, and John Day) have been declining over the past two decades. The John Day reservoir appears to be particularly vulnerable, where only 1 YOY sturgeon has been observed since 2012 during annual reservoir sampling. Based on the current length frequency distribution of sturgeon in the John Day reservoir, conservation metrics are likely not being met for the desired proportion of juveniles and subadults within the population. To address potential recruitment bottlenecks conceivably associated with spawning activity, we will use acoustic telemetry receivers throughout the John Day reservoir to characterize seasonal movements of adult White Sturgeon and formulate a habitat utilization model to identify likely spawning habitats. Additionally, if measurable YOY recruitment occurs within the next 6-9 years (estimated acoustic tag life), we hope to refine our understanding of environmental parameters conducive for spawning success. As effects of climate change become increasingly prevalent, having a contemporary understanding of White Sturgeon spawning patterns is essential. This research not only addresses critical uncertainties for lower Columbia River White Sturgeon, but also for North American sturgeon populations in general. Recruitment declines are being observed in many sturgeon populations—most famously in the Fraser River—and insights gained from this research may benefit other management agencies to help conserve these ancient fish that many people refer to as “living fossils.”
|Brill, G, MJ Davis, and A Carpenter. 2024. Quantifying adult white sturgeon (Acipensar transmontanus) movement in the John Day Reservoir, Columbia River. Oregon American Fisheries Society 2024 Annual Conference, Bend, Oregon.