Upstream Migration and Spawning Success of Chinook Salmon in a Highly Developed, Seasonally Warm River System

Abstract

This review summarizes what is known about the influence of water temperature and velocity on the migration and spawning success of an inland population of Chinook salmon Oncorhynchus tshawytscha. Models are then developed and used to illustrate how migration and spawning success might change if temperatures and velocities increase under a future climate. The illustration shows the potential for moderate increases in temperature and velocity to reduce homing and increase energy expenditure. Those two outcomes would reduce the abundance, productivity, and diversity of the population studied. Under the future scenario illustrated, it would become difficult for fish management actions alone to recover conservation-reliant populations of inland Chinook salmon.

Technical fishway passage structures provide high passage efficiency and effective passage for adult Pacific salmonids at eight large dams

“…Full-project passage estimates averaged 0.966 and were strikingly consistent across runs and years. Full-project fish passage times were much more variable, with median run×year×dam estimates ranging from 5–65 h. Passage time variability can be attributed to site-specific factors, but the diverse inter- and intra-annual river conditions encountered by radio-tagged fish were certainly influential, as documented in several previous studies [e.g., 43 , 55 , 89 , 90 ]. The monitored spring–summer Chinook Salmon populations encountered mean Columbia River discharge that ranged from ~3,500 m 3 /s in 2001 (a drought year) to ~11,000 m 3 /s during the near-record snowmelt runoff in 1997.…”

Climate vulnerability assessment for Pacific salmon and steelhead in the California Current Large Marine Ecosystem

“…Upper Willamette spring-run [119, 120] and Central Valley spring-run Chinook [121] face similar thermal challenges and high mortality between adult migration and spawning. Snake River fall-run Chinook did not score high in sensitivity to stream temperature , although adults do encounter high temperatures during late-summer migrations and have experienced compromised fecundity as a result [122, 123].…”

Behavioral thermoregulation by adult Chinook salmon (Oncorhynchus tshawytscha) in estuary and freshwater habitats prior to spawning

“…In this context, the increasing temperatures in Lake Washington are simply part of a much broader pattern of climate-driven change, although each river and lake has its own characteristics. These temperatures pose challenges for salmon; therefore, further information on how they confront thermal barriers will be important to determine their likelihood of survival (Hasler et al, 2012;Fenkes et al, 2016;Connor et al, 2019).…”

“…The system also poses special challenges for salmon, including an abrupt change in salinity from Puget Sound to the migration corridor above the locks and low dissolved oxygen (DO) levels in parts of the corridor. Increasing temperatures may adversely affect migration rate and spawning success of Chinook and other salmon species in this system, and elsewhere (Connor et al, 2019), but the nature and extent of the effects may depend on the behavioral thermoregulation and other tactics used by salmon migrating through these altered waterways.…”