Juvenile Salmonid Monitoring In Coastal Oregon and Lower Columbia Streams, 2013 Report Number: OPSW-ODFW-2014-1

Identification Information

Citation

Originator: Suring, E. and R. Constable

Publish Date: 2013

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 data from juvenile salmonid surveys across coastal Oregon in 2013. Results from this year are compared with our findings from 1998 – 2012. This unique, long term data set is used to monitor and describe trends in juvenile salmonid distribution and abundance for the three coho Evolutionarily Significant Units (ESU) and the four steelhead Distinct Population Segments (DPS) in coastal Oregon. Full reports from prior years are available at: https://nrimp.dfw.state.or.us/crl/default.aspx?pn=WORP. Oregon Coast Coho (OCC) ESU juvenile density estimates in 2013 were higher than any other year. The site occupancy rate in 2013 was similar to 2012. The latest three cohorts had the 1st, 3rd, and 2nd highest occupancy rates estimated over the duration of the project. Pool population estimates in 2013 were similar to 2012 and to the average of the last three cohorts. Overall, we observed a small, positive trend in occupancy and pool population estimates across the ESU from 1998-2013. In the Oregon Coast Coho ESU plots of parr abundance with female spawner abundance suggest limits to parr production in freshwater habitats. Southern Oregon Northern California Coho (SONCC) ESU juvenile density estimates were similar to 2012 and to the average since 1998. Site occupancy was higher in 2013 than in 2012 but these estimates were the two lowest observed. Pool population estimates were similar to 2012, but lower than in most years, with the exclusion of the 1998-2000 estimates. Regressions of both site occupancy and pool population estimates to survey year do not show detectable trend since the start of monitoring in the ESU. Lower Columbia River Coho (LCR) density, site occupancy, and pool population estimates were similar to 2012 and to the average since 2006. Regressions of both site occupancy and pool population estimates to survey year do not show detectable trends since the start of monitoring in the ESU. The Oregon Coast Steelhead DPS density estimate in 2013 was higher than in 2012 and the average since 2002. Pool population estimates in 2013 were similar to 2012 and to the average. Site occupancy estimates from 2013 were similar to 2012 and the latest three years have had the three highest occupancy estimates. In the Klamath Mountain Province (KMP) DPS, steelhead density in 2013 was the lowest recorded and similar to the next lowest estimate in 2012. Pool population estimates were similar to the average and to 2012. Site occupancy was the third lowest estimate, and similar to the low in 2012. Steelhead density estimates in the LCR and the Southwest Washington (SWW) DPSs in 2013 were similar to each other, to average, and to the 2012 estimates. Site occupancies in the LCR and SWW were similar to 2012 and to the average estimates for the DPSs. Point estimates for site occupancy in SWW for the last two years have been the first and second highest recorded. Pool population estimates for both DPSs were similar to 2012 and to the average. Analyses which included shallow pools (below our former 40cm maximum depth criteria) produced higher site occupancies and larger pool population estimates with proportionately smaller confidence intervals. Population estimates that included shallow pools tracked with those based on the former pool criteria.

Purpose:

Time Period of Content: 1998-2013

Geographic Extent: Klamath Mountain Province, Lower Columbia River

Status: Final

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Format: PDF File

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Is a physical copy maintained for reference at Headquarters? No