Status of Oregon Stocks of Coho Salmon, 2016, OPSW-ODFW-2017-3

Identification Information

Citation

Originator: Sounhein, B., E. Brown, M. Lewis and M. Weeber

Publish Date: November 2016

Online Link: None

BPA Project #:

Contact Information

Agency: Oregon Department of Fish and Wildlife

Name: Matt Weeber

Job Position: OASIS Program Analyst

Telephone: 541-757-5120

E-Mail Address: Matt.Weeber@oregonstate.edu

Description

Abstract: This report summarizes the results of status and trend monitoring for Oregon’s naturally spawning Coho Salmon, Oncorhynchus kisutch, through the 2016 run year (October 2016 through February 2017). Monitoring results include: 1. Abundance of naturally spawning Coho Salmon 2. Density (fish/mile) of naturally spawning Coho Salmon 3. Coho Salmon spawn timing and distribution 4. Proportion of hatchery (marked) Coho Salmon in naturally spawning populations Results in this report are based on data from randomly selected spawning surveys as well as alternative methods used in areas without adequate random surveys. Results for Coho Salmon standard spawning ground surveys and spawning surveys for other species are covered in data summaries and reports posted on an Oregon Department of Fish and Wildlife (ODFW) web page (see: http://odfw.forestry.oregonstate.edu/spawn/index.htm). Monitoring occurs at three hierarchical spatial scales, as defined by the National Marine Fisheries Service (NMFS): Evolutionarily Significant Unit (ESU); stratum; and Coho Salmon population. There are three Coho Salmon ESUs located entirely or partially within the State of Oregon: the Lower Columbia River (LCR) Coho ESU; the Oregon Coast (OC) Coho ESU; and the Southern Oregon/Northern California Coast (SONCC) Coho ESU. This report summarizes results for Coho Salmon populations in the portion of each ESU within the State of Oregon. In the Oregon portion of the LCR Coho ESU sufficient surveys were conducted in 2016 to meet the precision goal for the ESU, none of the three strata, and one of six sampled populations. The 2016 wild Coho Salmon spawner abundance for the LCR Coho ESU increased from 2015, but was still the fourth lowest observed in the 15 years of this monitoring effort. The proportion of hatchery Coho Salmon on natural spawning grounds was 7.8% in 2016, a record low for the LCR Coho ESU. This is the fourth consecutive year of setting a new record low for hatchery fish in this ESU. However, during the last four years we have not conducted random Coho Salmon surveys in the Youngs Bay and Big Creek populations, an area of traditionally high levels of hatchery spawners. Regional patterns in fish distribution, spawn timing, and hatchery proportion are apparent at both the stratum and population scales. Overall, Coho Salmon spawner run timing in 2016 was similar in duration and peak timing to previous years. In the OC Coho ESU sufficient surveys were conducted to meet the precision goal for the ESU, 3 of 4 strata, and only 1 of 21 populations (Lower Umpqua River). Wild spawner abundance in the OC ESU in 2016 was higher than in 2015, but still the third lowest observed over the past 10 years. There were no new record lows or highs in wild Coho Salmon abundance for any of the 24 populations or 5 strata. The proportion of hatchery fish on natural spawning grounds was 1.3% for the ESU as a whole. All naturally spawning Coho Salmon populations contained greater than 95% wild fish, except the Salmon (89.2%), North Umpqua (91.7%) and South Umpqua (63.2%) populations. Densities of wild Coho Salmon spawners in random surveys were lower than the 5 year average in all of the 21 populations. Percentage of random surveys occupied by wild Coho Salmon was below the 5 year average in 12 of 21 populations. Coho Salmon spawner run timing was different in duration and peak timing to long-term averages; two weak peaks occurred, one in late November/early December and another in late December. Inadequate funding and the need to update the sampling frame continue to hamper the monitoring of the Oregon portion of the SONCC Coho ESU. In 2016, no Generalized Random Tessellation Stratified (GRTS) surveys were conducted in the Oregon portion of this ESU. Monitoring of wild Coho Salmon spawners was based on the Huntley Park seining estimate. Wild Coho Salmon spawner abundance increased compared to the prior year, and was about the same as the 1994 through 2015 average. The proportion of hatchery Coho Salmon spawning naturally was higher than the previous nine years, but below the 22 year average. Without GRTS surveys, fish distribution and spawn timing were not evaluated in 2016.

Purpose:

Time Period of Content: 1998-2016

Geographic Extent: Lower Columbia River Basin and Oregon Coast

Status: Final

Use Constraints: Citation: Sounhein, B., E. Brown, M. Lewis and M. Weeber. 2017. Status of Oregon stocks of Coho Salmon, 2016. Monitoring Program Report Number OPSW-ODFW-2017-3, Oregon Department of Fish and Wildlife, Salem, Oregon.

Format: PDF file

Data Quality Information

Lineage-Source: Funds contributed in part by: Sport Fish and Wildlife Restoration Program administered by the U.S. Fish and Wildlife Service; Pacific Salmon Treaty and Pacific Coast Salmon Recovery Fund administered by the National Marine Fisheries Service; and State of Oregon (General and Lottery Funds).

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? No