Migration and survival of Okanagan River Sockeye Salmon Oncorhynchus nerka, 2012–2019

Animal Biotelemetry

Jeff Fryer¹  Kim Hyatt²  Elliot Koontz³  Katy Shelby³  Josh Murauskas³  Skyeler Folks⁴  Richard Bussanich⁴ 

[1] Columbia River Inter-Tribal Fish Commission, Portland, USA;Fisheries and Oceans Canada, Pacific Biological Station, Nanaimo, Canada;Four Peaks Environmental Science & Data Solutions, Wenatchee, USA;Okanagan Nation Alliance, Westbank, Canada;

关键词: Sockeye Salmon;    PIT tags;    Columbia River Basin;    Survival;   

DOI  :  10.1186/s40317-021-00262-y

来源: Springer

【 摘 要 】

BackgroundOkanagan River Sockeye Salmon Oncorhynchus nerka (Okanagan Sockeye) are one of two remaining self-sustaining Sockeye Salmon populations in the Columbia River Basin. We used detection histories of smolts implanted with passive integrated transponder (PIT) tags between 2012 and 2019 to estimate survival and behavioral metrics during reintroduction efforts and changing environmental conditions over the monitoring period.ResultsSmolts migrating to McNary Dam, whose route includes 130 km of the Okanagan River and 388 km of the Columbia River, generally had high survival (mean of 87.0% per 100 km) and fast migration speeds (up to 50 km/day) relative to other salmonids in the region. Smolt-to-adult returns (SARs) ranged from 0.4 to 6.1% and were greater for fish originating from Skaha Lake compared to cohorts tagged in Osoyoos Lake. Most adults returned after 2 years in the ocean (69%), followed by jacks (27%), and adults that spent 3 years at sea (4%), though Skaha Lake adults had a significantly younger age structure than cohorts from Osoyoos Lake. Survival of adults from Bonneville Dam (rkm 235) upstream to Wells Dam (rkm 830) was generally high (80–92%), and migration speed decreased in upstream reaches. Survival from Wells Dam to the Okanagan River was only estimable in 2018, where 64% of adults survived to the spawning grounds. The upstream migration of adult Okanagan Sockeye was significantly compromised during the drought of 2015 when less than 5% of Okanagan Sockeye that returned to the Columbia River reached spawning grounds.ConclusionsOur results indicate that Okanagan Sockeye have exceptional survival and migratory ability relative to other salmonids, though poor ocean conditions combined with warming water temperatures in freshwater habitats in recent years have the potential to devastate the population. The success of reintroduction efforts to increase spatial structure and diversity of Okanagan Sockeye is, therefore, critical to maintaining the population in years to come.

【 授权许可】

CC BY