Search
Search Results
-
11. [Article] Information Report 2018-01; Winter Habitat Condition of Oregon Coast Coho Salmon Populations, 2007-2014
Abstract -- In this report we summarize results of eight years (2007-2014) of habitat surveys for 18 independent Oregon coast coho salmon populations across four monitoring strata (North Coast, Mid Coast, ...Citation Citation
- Title:
- Information Report 2018-01; Winter Habitat Condition of Oregon Coast Coho Salmon Populations, 2007-2014
Abstract -- In this report we summarize results of eight years (2007-2014) of habitat surveys for 18 independent Oregon coast coho salmon populations across four monitoring strata (North Coast, Mid Coast, MidSouth Coast, and Umpqua) in the Oregon Coast Coho Salmon Evolutionary Significant Unit (ESU). We also sampled dependent population blocks across three monitoring strata (North Coast, Mid Coast, and Mid-South Coast). Using a spatially balanced site selection process (Generalized Random Tessellation Stratification; GRTS) we surveyed 451 unique sites within the range of coho salmon spawning or rearing. With the exception of the 2014 survey year, habitat data were collected during winter conditions (February – March). Habitat sampled in 2014 occurred within the summer field season (June – September). We used a Habitat Limiting Factors Model (HLFM) to estimate habitat capacity for winter coho parr and the HabRate model to assess habitat quality for each surveyed stream reach. HLFM estimates were expanded based on the total coho distribution in each population. Based on the habitat data the HLFM predicted the Floras population could support the highest density of juvenile coho (1568 parr/km), while the streams in the Siltcoos watershed could support the least (290 parr/km). At the ESU-level, there was no detectable change of high quality rearing habitat (= 1850 parr/km) when compared to previous studies, but changes were observed among populations over the course of these survey years. We compared individual habitat metrics across populations, land use, geology, and between independent and dependent populations. While no significant differences were observed between independent and dependent populations, differences in habitat metrics were detected among individual populations, land use types, and geologies. In addition, we detected a difference in reproductive habitat quality (spawning and emergence) between both populations and land use types.
-
12. [Article] Information Report 2018-04, Smolt Abundance Estimates for the Oregon Coast Coho Evolutionarily Significant Unit
Abstract -- Analysis of Coho Salmon (Oncorhynchus kisutch) smolt abundance can provide insight on freshwater habitat capacity and factors affecting salmonid persistence. To explore these relationships ...Citation Citation
- Title:
- Information Report 2018-04, Smolt Abundance Estimates for the Oregon Coast Coho Evolutionarily Significant Unit
Abstract -- Analysis of Coho Salmon (Oncorhynchus kisutch) smolt abundance can provide insight on freshwater habitat capacity and factors affecting salmonid persistence. To explore these relationships we linked multi-year data sets of overwinter survival rates from three streams within the Oregon Coast Coho Evolutionarily Significant Unit (OCC) to summer parr abundance estimates from calibrated OCC-wide snorkel survey counts to estimate annual Coho Salmon smolt abundance from 2000-2017. Smolt abundance estimates ranged from a low of 0.9 million in 2000 to a high of 4.1 million in 2013 within the OCC. Accuracy of the smolt abundance estimates was tested using two datasets: (i) adult abundance modeled from the corresponding smolt abundance estimate was compared with adult abundance derived empirically from spawning ground surveys and (ii) our smolt abundance estimates were compared with smolt abundance estimates from trapping efforts in select basins within the OCC. Adult abundance modeled from smolt abundance estimates was highly correlated with adult abundance from spawning ground surveys (r = 0.88, p < 0.001) and smolt abundance estimates correlated with abundance from smolt trapping efforts (r = 0.81, p <0.001). Graphical relationships between smolt abundance and parental abundance suggest that freshwater productivity may be limited in the OCC by density dependent processes at spawner levels observed since 1998. Additionally, smolt abundance estimates have potential use as a variable in adult forecast models and could be used to assess trends in freshwater productivity and to probe factors of density dependence.
-
13. [Article] Stream Habitat Conditions in Western Oregon 2005 Monitoring Report Report Number: OPSW-ODFW-2007-5
Abstract -- Monitoring programs under the Oregon Plan for Salmon and Watersheds were designed to assess the status and trend in fish populations and aquatic habitat in Oregon’s coastal basins. Although ...Citation Citation
- Title:
- Stream Habitat Conditions in Western Oregon 2005 Monitoring Report Report Number: OPSW-ODFW-2007-5
Abstract -- Monitoring programs under the Oregon Plan for Salmon and Watersheds were designed to assess the status and trend in fish populations and aquatic habitat in Oregon’s coastal basins. Although the Oregon Plan for Salmon and Watersheds was initiated in response to the petition to list Oregon coastal coho salmon (Oncorhynchus kisutch) as threatened under the Endangered Species Act (ESA), monitoring was subsequently expanded to include other salmonids. Through coordinated surveys we are able to evaluate freshwater habitat, fish distribution, and abundance of juvenile and adult coho salmon and steelhead trout. The habitat survey project has the broadest geographic scope of inference and ties to other program components as well – basin surveys, surveys at habitat restoration sites, adult and juvenile coho surveys, and life cycle watersheds (Flitcroft et al. 2002). The Oregon Plan facilitated cooperation and partnerships to study the contemporary life history dynamics of coho salmon in the Oregon coastal ESU (Evolutionary Significant Unit). A viability and status assessment of Oregon coastal Coho (Chilcote 2005) and the Conservation Plan for the Oregon Coast Coho Evolutionary Significant Unit (Nicholas 2006) evaluated the relationship of aquatic habitat to the productivity of coho salmon populations and recommended actions to promote recovery. The habitat portion of the viability assessment was based on a review of aquatic and riparian habitat collected by the Aquatic Inventories Project (ODFW) from 1990 to 2004 (Rodgers et al. 2005). The authors of the habitat assessment (Rodgers et al 2005) and viability assessment (Chilcote 2005) concluded that coho productivity in 22 coastal coho populations was limited by the complexity of stream habitat used by juvenile coho during their first winter of freshwater residence. The term “stream complexity” integrates geomorphic and structural characteristics of streams and associated aquatic habitat. Complex geomorphic features may be observed in low gradient streams flowing through wide valley floors with multiple channels and off-channel habitats. Structural complexity refers to the size and configuration of pools, large wood pieces and jams, substrate, and undercut banks. The combination of geomorphic and structural features provides cover and refugia during high winter flows for juvenile coho. Stream reaches that can or have the potential to create these conditions are commonly located in lower reaches of moderate size streams in areas with wide valley floors and are considered to contain high quality habitat for juvenile coho. Burnett et al. (2007) developed spatial models to estimate high-quality habitat rearing potential, termed intrinsic potential, in coastal streams. A stream’s intrinsic potential was modeled using valley width, gradient, and stream flow. Historically, streams identified as having high intrinsic potential may have been the most productive for juvenile coho salmon; restoration of these reaches may be the key to recovery of coho salmon. The viability assessment and Coho Plan recommend that we monitor the trends in total amount and spatial distribution of these habitats in coastal drainages. This report discusses the findings from aquatic habitat surveys conducted in summer 2005 in coastal drainages. Our objectives are to describe and compare channel morphology, instream habitat and complexity, and riparian conditions in all wadeable streams in five monitoring areas. The sample design permitted us to post stratify the sample sites into three additional frames: sites within coho and steelhead distribution, sites outside coho distribution, and sites within high intrinsic potential for coho. We also used two habitat models to integrate habitat attributes to describe the habitat quality and capacity for different life stages of juvenile coho and steelhead.
-
14. [Article] Juvenile Salmonid Monitoring In Coastal Oregon and Lower Columbia Streams, 2016 Report Number: OPSW-ODFW-2017-1
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 ...Citation Citation
- Title:
- Juvenile Salmonid Monitoring In Coastal Oregon and Lower Columbia Streams, 2016 Report Number: OPSW-ODFW-2017-1
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.
-
15. [Article] Effectiveness Monitoring Report for the Western Oregon Stream Restoration Program, 1999-2008 Report Number: OPSW-ODFW-2010-6
Abstract -- State and federal agencies have invested millions of dollars to restore streams and watersheds in the Pacific Northwest over the past two decades. In Oregon alone, over 500 million dollars ...Citation Citation
- Title:
- Effectiveness Monitoring Report for the Western Oregon Stream Restoration Program, 1999-2008 Report Number: OPSW-ODFW-2010-6
Abstract -- State and federal agencies have invested millions of dollars to restore streams and watersheds in the Pacific Northwest over the past two decades. In Oregon alone, over 500 million dollars has been spent on completed projects from 1995 to 2007 (Oregon Watershed Enhancement Board 2009). Restoration practitioners have distributed the investment among watershed scale activities such as road repair, dam removal, and upland management, and stream scale activities such as passage, instream complexity, and riparian plantings. The Western Oregon Stream Restoration Program (WOSRP) was established to work in cooperation with private and corporate landowners to restore stream habitat for juvenile and adult salmonids. In addition to the WOSRP, the Oregon Watershed Enhancement Board (OWEB) funds restoration projects with local watershed councils, who commonly partner with state and federal agencies. Eight WOSRP restoration biologists in Tillamook, Newport, Charleston, Gold Beach, Roseburg, Clackamas, and Salem select sites and implement projects consistent with the criteria described in Thom et al (2001). A monitoring component is integrated in the program, with surveys coordinated and reported by a biologist in Corvallis. The goal of the monitoring program is to assess the long term effectiveness of instream restoration projects implemented by WOSRP, and to evaluate progress towards salmon conservation and recovery goals in Oregon’s coastal basins. The WOSRP restoration sites are distributed throughout the Willamette, Lower Columbia, and coastal drainage's. Restoration treatments added large wood and/or boulders, improved fish passage, planted trees in riparian areas, or were a combination of the three. Large wood was placed in complex jams at intervals throughout the stream to increase stream roughness and complexity. Boulders were sometimes used in conjunction with wood jams to provide stability to the structures, and prevent large wood from moving downstream and posing a hazard to culverts and bridges. Bedrock dominated streams were often treated with boulders to collect gravel and cobble, intended to aggrade the streambed. In the future, large wood may be added to these streams. Fish passage projects opened previously inaccessible habitat to juvenile and/or adult salmonids while riparian plantings and fencing were designed to improve riparian vegetation and bank structure. The project length varied from site to site. Fish passage sites were quite short, but provided access to kilometers of fish habitat, and large wood sites were up to several kilometers in length. Large wood and boulder placement projects have become commonplace in the Pacific Northwest to restore complex stream habitat for juvenile coho and other salmonids (Katz et al. 2007, Roni et al. 2008). Detailed assessments have been published for individual projects or experiments (e.g. Moore and Gregory, 1988, Nickelson et al. 1992, Cederholm et al.1997). More extensive evaluations have used a post treatment design (Hicks et al 1991, Roni and Quinn 2001), but none have used a pre- and post treatment design. In this paper we evaluate habitat changes at 103 restoration projects in western Oregon from pre-treatment to one year post treatment to 6 years following treatment. Projects commonly treated 0.5 – 1 km of stream, but some extended up to 6 km. The projects we evaluated in this paper were treated with large logs, usually arranged in jams, and were not cabled or driven into banks or bottom. As of 2008, the OWEB and WOSRP projects have treated approximately 750 km of stream with large wood (Figure 1), 120 km with boulders, and over 4,000 km of stream have been made accessible by replacing and/or removing culverts. Each year, OWEB receives 210 grant applications for restoration projects. These projects generally adhere to a similar selection process and design, so the results of this study can be expected to apply more broadly within the Pacific Northwest. Roni et al (2008), in a synthesis paper, summarized many of the potential physical benefits of restoration; these include pool depth and frequency, habitat complexity, woody debris, and sediment retention and quality of spawning gravel. Some projects in deeply incised channels have reduced the incision and increased bed elevation. Evaluations of biological responses have been confounded by natural variability of populations, duration of study, or length of stream examined. For example, determination of success based on spawning ground counts is problematic because of variation in ocean survival. However, longer duration and watershed scale studies have shown positive responses of juvenile and adult salmon (Johnson et al 2005). Burnett et al. (2008) conducted a systematic review of peer-reviewed articles to examine the effects of large wood placement on salmonid abundance, growth, or survival, or on overall stream habitat complexity. Few publications were both relevant and met the rigorous standards outlined in their review. Although the review supported short term improvements in habitat complexity, the relationship to salmonid productivity was less definitive. Notable exceptions included Johnson et al. (2005) cited above, and Solazzi et al. (2000). An alternative approach to directly assessing biological response is to model potential changes in abundance or productivity. The Habitat Limiting Factors Model (Reeves et al. 1989, Nickelson et al.1992a, Nickelson 1998) was developed to quantify the carrying capacity of coastal streams for juvenile coho during the summer and winter. Use of this model is appropriate because most of the instream restoration projects in western Oregon were intended to improve habitat for juvenile coho. In this paper, we evaluated the physical response directly, and quantified the potential response of juvenile coho salmon by application of the Habitat Limiting Factors Model. Project effectiveness monitoring requires linking the restoration treatment to improved physical conditions for and biological response of salmon (Katz et al. 2007) and defining desired outcomes (Rumps et al. 2007). Because the WOSRP projects were designed to improve ecological and hydrologic stream function specifically for salmonids, we evaluated 1) retention of wood structures, 2) natural recruitment of additional wood, 3) increase in pool number, area, and depth, 4) retention of gravels and sorting of finer substrates, and 5) increase in channel complexity – secondary channels and off-channel habitats. Biological evaluation was based on estimates of the potential carrying capacity for juvenile coho during the overwinter life stage. The primary objectives of this evaluation are to test for these changes one year following treatment and 6 years following treatment. Secondarily, we evaluated the response of the projects by geographic location and position along the stream network. Previous WOSRP monitoring reports (e.g. Jacobsen and Jones 2003, Jacobsen et al. 2007) have focused on conditions one year following treatment, with relatively few sites assessed 2-3 years following restoration. Since 2003, the restoration projects have increased in complexity – more and larger pieces and jams, and treated more kilometers of stream length per site. The WOSRP program has provided a unique opportunity to evaluate the effects of restoration projects over longer times and broader geographic scales than previously feasible. We have been surveying the restoration sites in both summer and winter to monitor changes in stream habitat and evaluate the success of treatments, such as the placement of wood and/or boulders and fish passage. Surveys are logistically easier to manage in the summer, but surveys conducted during the winter provide a more timely and accurate assessment of over-winter rearing potential for juvenile coho. Because we have paired surveys, we are able to assess the added value of revisits across seasons. We test the hypothesis that habitat characteristics at the restoration sites do not change from summer to winter. The findings permit us to modify the survey program if the information is duplicative, and use the resources in another fashion.
-
16. [Article] Recovery of Wild Coho Salmon In Salmon River Basin, 2008-2010 Report Number: OPSW-ODFW-2011-10
Abstract -- Hatcheries have been a centerpiece of salmon management in the Pacific Northwest for more than a century but recent evidence of adverse interactions between hatchery and naturally-produced ...Citation Citation
- Title:
- Recovery of Wild Coho Salmon In Salmon River Basin, 2008-2010 Report Number: OPSW-ODFW-2011-10
Abstract -- Hatcheries have been a centerpiece of salmon management in the Pacific Northwest for more than a century but recent evidence of adverse interactions between hatchery and naturally-produced salmon have resulted in substantial changes in many hatchery programs. In 2007 the Oregon Department of Fish and Wildlife terminated a 30-year artificial propagation program for coho salmon in the Salmon River basin after a status assessment concluded that wild population viability was threatened by hatchery effects on salmon productivity (Chilcote et al. 2005). Hatchery-reared coho comprised 50-100% of the naturally spawning population in recent years. Low productivity was reflected in a low spawner to recruit ratio, and life-stage specific survival was lower than that of nearby populations. The temporal distribution of adult spawning in the basin was truncated and peaked 1.5 months earlier relative to the pre-hatchery period and adjacent coastal populations. The cessation of hatchery releases into Salmon River not only removed the primary factor believed to limit productivity of the local population, it also constituted a rare management experiment to test whether a naturally-spawning population can recover from a prolonged period of low abundance after interactions with hatchery-produced coho salmon are eliminated. This report summarizes the results of coho population studies at Salmon River for the first three years after the hatchery program was discontinued. The study in Salmon River is timely because ecological interactions between hatchery and wild fish have been implicated in the reduced survival and decreased productivity of wild coho and other salmonid populations (Nickelson 2003, Buhle et al. 2009, Chilcote et al. 2011). Recent studies involving a diversity of salmonid species and watersheds have shown a negative relationship between hatchery spawner abundance and wild population productivity regardless of the duration of hatchery influence (Chilcote et al. 2011). Yet neither the mechanisms of these productivity declines nor their potential reversibility have been investigated. Recent management changes at Salmon River provide an opportunity to experimentally evaluate coho salmon survival and productivity following the elimination of a decades-long hatchery program. The results will provide new insights into the reversibility of hatchery effects and the rate, mechanisms, and trajectory of response by a naturally spawning coho salmon population. Hatchery programs have been shown to change the timing and distribution of naturally spawning adults, but ecological and genetic influences on the spatial structure and life history diversity of juvenile populations are poorly understood. Conventional understanding of the life history of juvenile coho has presumed a relatively fixed pattern of rearing and migration. However, recent studies have found much greater variation in juvenile life history and habitat-use patterns than previously expected (Miller and Sadro 2003, Koski 2009), including evidence that estuaries may play a prominent role in the life histories of some coho salmon populations. A recent study in the Salmon River basin found considerable diversity in the life histories of juvenile Chinook salmon, including extended rearing by fry and other subyearling migrants within the complex network of natural and restored estuarine wetlands (Bottom et al. 2005). Unfortunately, interpretation of juvenile life history variations at Salmon River was confounded by the Chinook hatchery program, which has concentrated spawning activity in the lower river near the hatchery and may directly influence juvenile migration and rearing patterns. Discontinuation of the coho hatchery program at Salmon River provides an opportunity to quantify changes in juvenile life history following the elimination of all hatchery-fish interactions with the naturally spawning population. Such responses may provide important insights into the mechanisms of hatchery influence on wild salmon productivity and population resilience. Our research integrates adult and juvenile life stages, examines linkages to physical habitat conditions in fresh water and the estuary, and describes variability between juvenile performance and adult returns. It also monitors the coho salmon population across habitat types and life history stages to identify population responses at a landscape scale. We will determine productivity and survival at each salmon life stage and monitor the response of the adult population following the cessation of the coho salmon hatchery program. From these indicators, we will determine the potential resiliency of the coho salmon population, and evaluate the biological benefits or tradeoffs of returning the ecosystem to natural salmon production. Our study design encompasses four population phases: (1) pre-hatchery conditions (Mullen 1979), (2) dominance by hatchery-reared spawners (2008), (3) first generation naturally produced juveniles (2009-2011), and (4) second generation naturally produced juveniles (starting in 2012). This research will validate assumptions about factors limiting coho recovery and determine whether recovery actions have been effective. Here, we report on findings from 2008-2010 to address four principal objectives: 1. Quantify life stage specific survival and recruits per spawner ratio of the coho salmon population before and after hatchery coho salmon are removed from Salmon River. 2. Assess whether the Salmon River coho population is limited by capacity and complexity of stream habitat. 3. Describe the diversity of juvenile and adult life histories of coho salmon in the Salmon River basin, and estimate the relative contributions of various juvenile life histories to adult returns. 4. Determine seasonal use of the Salmon River estuary and its tidally-inundated wetlands by juvenile coho salmon. The field sampling that supported the study on coho salmon also captured Chinook salmon and steelhead and cutthroat trout during routine sampling in the watershed and estuary. This report emphasizes coho salmon results, but also summarizes catch, distribution, and migration data for other salmonids to compare densities and abundances in freshwater and the estuary. Additional results for Chinook, steelhead, and cutthroat are presented in Appendix A. See Stein et al. (2011) for more detailed information on life history diversity, migration patterns, habitat use, and abundance of cutthroat trout.