Juvenile Salmonid Monitoring In Coastal Oregon and Lower Columbia Streams, 2016 Report Number: OPSW-ODFW-2017-1

Identification Information

Citation

Originator: Suring, E., and R. Constable

Publish Date: 2016

Online Link: None

BPA Project #:

Contact Information

Agency: Oregon Department of Fish and Wildlife

Name: Ronald Constable

Job Position: NRS-2 Assistant Project Leader

Telephone: 541-757-5107

E-Mail Address: ron.constable@oregonstate.edu

Description

Abstract: This report analyzes monitoring data for juvenile Coho Salmon in three Evolutionarily Significant Units (ESUs) and juvenile steelhead in four Distinct Population Segments (DPSs) in western Oregon. Monitoring data are used to evaluate trends in salmonid distribution and abundance, which inform conservation and recovery decisions. The analysis in this report spans the years 1998-2016. Previous annual reports can be found at: https://nrimp.dfw.state.or.us/crl/default.aspx?pn=WORP. Juvenile Coho Salmon: For both the Oregon Coast Coho (OCC) and Lower Columbia River (LCR) ESUs, abundance estimates were lower in 2016 relative to the average from the 2013-2015 broods. The 2016 LCR abundance estimate was the lowest recorded in the 11 years of monitoring in this ESU. In the Southern Oregon Northern California Coho (SONCC) ESU the 2016 abundance estimate was similar to the average of the estimates for the 2013- 2015 broods. The 2016 estimate of site occupancy, relative to the estimate for the 2013- 2015 broods, was lower in the LCR, and similar in the OCC and the SONCC. As with the abundance estimate for the LCR, the 2016 estimate of site occupancy was the lowest recorded since monitoring began in the ESU. In the OCC there is some indication from Coho Salmon survey data that freshwater productivity rates are regulated by compensatory density dependence at one or several early life stages. In the OCC metapopulation, the spawner:summer parr (recruit) curve is sigmoidal in years of higher female spawner abundance, suggesting some factor (or combination of factors) that sets juvenile carrying capacity. A density dependent pattern has not been observed in the LCR, likely due to relatively low seeding levels in the ESU. For the SONCC there are insufficient adult data to perform these analyses. Juvenile Steelhead: For the Oregon Coast (OC) and the Klamath Mountains Provence (KMP) DPSs, the average of the abundance estimates for the 2014-2016 broods was similar to the average for the 2010-2013 broods. The 2016 abundance estimate was similar to the average of the 2006-2015 estimates in the South West Washington (SWW) DPS and lower than the average of the 2006-2015 estimates in the Lower Columbia River (LCR) DPS. Site occupancy estimates in the OC and KMP in the 2014-2016 broods were similar to the estimates for the 2010-2013 broods. Site occupancy estimates in 2016, relative to the average of the 2006-2015 estimates, were similar in the SWW and lower in the LCR. From 1998 to 2009 pools were required to be =40cm in maximum depth to meet survey protocols. This was changed to =20cm in maximum depth in 2010. Analyses based on the =20cm maximum depth criteria, relative to the =40cm maximum depth criteria, typically produce increases in site occupancy rates and larger abundance estimates with proportionately smaller confidence intervals. Abundance estimate trends that included shallow pools tracked with those based on the former pool criteria.

Purpose:

Time Period of Content: 2013-2016

Geographic Extent: Oregon coast, Columbia River

Status: Final

Use Constraints:

Format: PDF file

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Is a physical copy maintained for reference at Headquarters? No