Lower Columbia River Juvenile Detection Program (CLBMON-29). Year 10 Data Report

Author: B.C. Hydro

This report describes the tenth (2017) year of monitoring in the LCR as a component of the water use plan under the project: CLBMON-29 Lower Columbia River Juvenile Sturgeon Detection. Specific components of the study are to: 1. Monitor distribution of both larvae and juvenile life history stages. 2. Estimate growth and survival of both wild and hatchery origin White Sturgeon. 3. Describe sex and stage of maturity of hatchery origin White Sturgeon. The LCR Juvenile Sturgeon Detection Program in 2017 was designed to describe life history aspects of juvenile White Sturgeon, as well as provide input to the ongoing consideration of recruitment failure hypotheses, the evaluation of the effects of future management responses, and information to guide conservation culture stocking targets. As stated in the terms of reference for the work, the objectives of this program will have been met when: 1. The development, condition, drift and movement behaviours, growth, and survival of yolk-sac larvae and juvenile sturgeon are assessed with sufficient consistency to describe annual trends. 2. Early life stage distributions over time, including location and parameters of yolk-sac larvae and juvenile rearing habitats, are adequately defined. 3. Relationships between yolk-sac larvae and juvenile habitat quality and variations in discharge from upstream dams and water levels of Lake Roosevelt reservoir are quantified. 4. Assessment of the effects of current operations and determine feasibility of management responses are completed. The scope of the juvenile program focuses on data collection to define yolk-sac larvae and juvenile habitat conditions, determine the effect of existing hydraulic conditions, and identify and assess the most suitable of several management responses to be considered in lieu of operational changes.

MQ1: What are the relative abundance, survival rates, and distribution locations of larvae and juvenile White Sturgeon in the lower Columbia River under current operating parameters?
Larval Stage: Relative abundance and survival of larval White Sturgeon will be difficult to address given limitations related to effectively sampling this life stage. However, data pertaining to timing, locations, and frequency of spawning in the lower Columbia River (LCR) has been collected. Larvae have been collected near the HLK/ALH spawning area, downstream of Kinnaird, and from the Waneta spawning site downstream into the US portion of the LCR. Larval catch has predominantly consisted of young (stages <40) individuals; however older feeding age larvae (>stage 40; >10 days post hatch) have been collected downstream of HLK/ALH and Waneta. Further, large numbers of later stage larvae (>stage 45) collected on the US side of the Columbia River suggests that hiding habitat exists from the Canadian/US border downstream to North Port, Washington.
Juvenile Stage: Survival of hatchery origin juveniles has been higher than originally predicted. This has resulted in a large hatchery population estimated at more than 6,000 individuals in the Canadian section of the Transboundary Reach. A recent review of White Sturgeon capture data has identified high variability in maternal family representation of hatchery-origin juveniles in both the Canadian and U.S. portions of the Transboundary Reach of the Columbia River. Unequal family representation presents a substantial genetic risk to the long term viability of the White Sturgeon population in the Transboundary Reach, and the UCWSRI TWG are working on conservation measures to address this issue. One measure has been implemented is the Conservation Aquaculture Program transitioning (2011 in WA and 2015 in BC) entirely to collecting naturally produced embryos and larvae for hatchery rearing – an approach that has demonstrated genetic benefits over broodstock based aquaculture programs.
Distribution of juveniles has been assessed extensively throughout the LCR, and is restricted primarily to slower moving habitats like eddys and deeper runs. While these habitats are available primarily in the upper (Robson to Genelle) or lower (Beaver Creek to Waneta) sections of the river, hatchery origin fish are captured throughout the entire LCR.
MQ2: What are the physical and hydraulic properties of this habitat that define its suitability as juvenile sturgeon habitat?
Juveniles are selecting deeper (>10 m), slow moving (< 1.0 m/s), habitats with smaller substrates (e.g., sand, small gravel). These habitats are widely distributed through the upper reaches (e.g., Robson) and are restricted to eddy habitats downstream of the Kootenay River confluence to the US border. MQ3: How do normal river operations affect larval habitat conditions in the lower Columbiaa River? At the present time more data are required to address this question. Spawning has been identified at several locations but the quantity and quality of spawning habitat is currently unknown. Based on the capture of primarily yolk-sac larvae within a few days of hatch (stages <40), the spawning habitat throughout the LCR was presumed to be poor for hiding after hatch. However, increased drift net effort in 2015, 2016 and 2017 compared to all previous sampling years downstream of the Waneta spawning site indicated that a percentage of larvae hide until feeding age before initiating dispersal downstream. Additionally, older feeding larvae are collected in large numbers on the US side of the Columbia River suggesting that hiding habitat exists from the Canadian/US border downstream to North Port, Washington. A specific Columbia Water Use Plan physical works program (CLBWORKS-27) is evaluating habitat conditions for early life stages at the three spawning locations in the lower Columbia River in 2018. Results are expected to help inform information collected under this monitoring program. MQ4: How do normal river operations affect juvenile habitat conditions in the lower Columbia River during dispersal and on a seasonal basis? The distribution of juvenile White Sturgeon in the LCR is restricted to deeper, slower moving, habitats. These habitats are currently not limited by the operational regime of the river, irrespective of the time of year.

MQ1: What are the relative abundance, survival rates, and distribution locations of larvae and juvenile White Sturgeon in the lower Columbia River under current operating parameters?
Larval Stage: Relative abundance and survival of larval White Sturgeon will be difficult to address given limitations related to effectively sampling this life stage. However, data pertaining to timing, locations, and frequency of spawning in the lower Columbia River (LCR) has been collected. Larvae have been collected near the HLK/ALH spawning area, downstream of Kinnaird, and from the Waneta spawning site downstream into the US portion of the LCR. Larval catch has predominantly consisted of young (stages <40) individuals; however older feeding age larvae (>stage 40; >10 days post hatch) have been collected downstream of HLK/ALH and Waneta. Further, large numbers of later stage larvae (>stage 45) collected on the US side of the Columbia River suggests that hiding habitat exists from the Canadian/US border downstream to North Port, Washington.
Juvenile Stage: Survival of hatchery origin juveniles has been higher than originally predicted. This has resulted in a large hatchery population estimated at more than 6,000 individuals in the Canadian section of the Transboundary Reach. A recent review of White Sturgeon capture data has identified high variability in maternal family representation of hatchery-origin juveniles in both the Canadian and U.S. portions of the Transboundary Reach of the Columbia River. Unequal family representation presents a substantial genetic risk to the long term viability of the White Sturgeon population in the Transboundary Reach, and the UCWSRI TWG are working on conservation measures to address this issue. One measure has been implemented is the Conservation Aquaculture Program transitioning (2011 in WA and 2015 in BC) entirely to collecting naturally produced embryos and larvae for hatchery rearing – an approach that has demonstrated genetic benefits over broodstock based aquaculture programs.
Distribution of juveniles has been assessed extensively throughout the LCR, and is restricted primarily to slower moving habitats like eddys and deeper runs. While these habitats are available primarily in the upper (Robson to Genelle) or lower (Beaver Creek to Waneta) sections of the river, hatchery origin fish are captured throughout the entire LCR.
MQ2: What are the physical and hydraulic properties of this habitat that define its suitability as juvenile sturgeon habitat?
Juveniles are selecting deeper (>10 m), slow moving (< 1.0 m/s), habitats with smaller substrates (e.g., sand, small gravel). These habitats are widely distributed through the upper reaches (e.g., Robson) and are restricted to eddy habitats downstream of the Kootenay River confluence to the US border. MQ3: How do normal river operations affect larval habitat conditions in the lower Columbiaa River? At the present time more data are required to address this question. Spawning has been identified at several locations but the quantity and quality of spawning habitat is currently unknown. Based on the capture of primarily yolk-sac larvae within a few days of hatch (stages <40), the spawning habitat throughout the LCR was presumed to be poor for hiding after hatch. However, increased drift net effort in 2015, 2016 and 2017 compared to all previous sampling years downstream of the Waneta spawning site indicated that a percentage of larvae hide until feeding age before initiating dispersal downstream. Additionally, older feeding larvae are collected in large numbers on the US side of the Columbia River suggesting that hiding habitat exists from the Canadian/US border downstream to North Port, Washington. A specific Columbia Water Use Plan physical works program (CLBWORKS-27) is evaluating habitat conditions for early life stages at the three spawning locations in the lower Columbia River in 2018. Results are expected to help inform information collected under this monitoring program. MQ4: How do normal river operations affect juvenile habitat conditions in the lower Columbia River during dispersal and on a seasonal basis? The distribution of juvenile White Sturgeon in the LCR is restricted to deeper, slower moving, habitats. These habitats are currently not limited by the operational regime of the river, irrespective of the time of year.