The Effect of Moderately Increased and Variable Raceway Flow Rates on Juvenile Physiology, Survival and Adult Return of Hatchery-reared Chinook Salmon Oncorhynchus tshawytscha, Information Reports 2005-02

Identification Information

Citation

Originator: Hoffnagle, T. L. R. W. Carmichael, P. J. Keniry, T. A. Whitesel, and S. J. Parker

Publish Date: April 2005

Online Link: https://www.fws.gov/lsnakecomplan/Reports/ODFWreports.html

BPA Project #:

Contact Information

Agency: Oregon Department of Fish and Wildlife

Name: Joseph Feldhaus

Job Position: Assistant Project Leader

Telephone: 541-962-3724

E-Mail Address: Joseph.Feldhaus@odfw.oregon.gov

Description

Abstract: To improve post-release survival in nature, salmon hatcheries have begun to better simulate natural conditions, such as increasing the flow rate in raceways to a rate similar to that seen in nature. This “exercises” the salmon in the expectation that improving swimming ability will improve their survival during smolt migration, resulting in better survival to adulthood. We examined the effect of variable moderate flow rates (0.25-0.75 body lengths per second) on growth and physiology of juvenile chinook salmon Oncorhynchus tshawytscha and their ability to withstand acute stress, survive downstream migration and return as adults. Over the 5-8 month sampling period, mean length, weight and condition factor increased similarly in both the exercised and control groups. Mean plasma glucose levels were similar in each treatment group and peaked in early spring of each year. Hematocrit did not vary in a consistent trend for either treatment group or cohort. Hepatosomatic index (HSI) decreased in the 1994 cohort control group and increased in the 1995 cohort exercised group. In both cohorts, liver glycogen levels decreased through the winter and continued to decline in the 1994 cohort while in the 1995 cohort there was a significant peak in liver glycogen levels in each group during March 1997. Following stress, mean plasma glucose and cortisol levels increased, mean hematocrit varied inconsistently, mean HSI generally decreased, mean CSI decreased inconsistently in the 1995 cohort and mean liver glycogen level did not change. Mean survival of smolts to Lower Granite Dam did not vary between treatment groups with detection rates ranging narrowly from 58.7-60.7%. Mean percentage of adults returning at age 3 was higher for exercised salmon than for controls and a higher percentage of controls returned at age 5 than exercised salmon. Mean smolt-to-adult survival rate varied significantly between cohorts but there was no difference in mean survival rate between treatment groups. Variation within cohorts was greater between the exercised raceways than the controls, indicating that additional years of study are needed to compensate for large differences in survival between cohorts to make any conclusions regarding differences between treatments. Our results provide little evidence that rearing chinook salmon under a moderately increased and seasonally variable flow regime provided any benefit to the salmon over a steady low flow. Lower Snake River Compensation Plan (LSRCP) ODFW- Eastern Oregon Fish Research (EOFR)

Purpose:

Time Period of Content: 1994-1997

Geographic Extent: Lookingglass Hatchery and Rapid River

Status: Final

Use Constraints:

Format: pdf

Data Quality Information

Lineage-Source:

Data Information

No data information was supplied.

Entity and Attribute Information

Attributes Description: Field attribute information is available in the attached file(s).

Is a physical copy maintained for reference at Headquarters? Yes