Current landscapes and legacies of land-use past: understanding the distribution of juvenile coho salmon (Oncorhynchus kisutch) and their habitats along the Oregon Coast, USA

The Oregon Coast landscape displays strong spatial patterns in air temperature, precipitation, and geology, which can confound our ability to detect relationships among land management, instream conditions, and fish at broad spatial scales. Despite this structure, we found that a suite of immutable or intrinsic attributes (e.g., reach gradient, drainage area, elevation, and percent weak rock geology of the catchments draining to each of our 423 study reaches) could explain much of the variation in pool surface area across the landscape and could contribute to an estimate of how many juvenile coho salmon (Oncorhynchus kisutch) one might expect to find in those pools. Further, we found evidence of differences in pool surface area across land ownership categories that reflect differing management histories. Our results also suggest that historical land and river management activities, in particular splash dams that occurred at least 50 years ago, continue to influence the distribution of juvenile coho salmon and their habitats today.

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Use of Hatchery Coho Salmon (Oncorhynchus kisutch) Presmolts to Rebuild Wild Populations in Oregon Coastal Streams

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f86-303 ◽

1986 ◽

Vol 43 (12) ◽

pp. 2443-2449 ◽

Cited By ~ 81

Author(s):

Thomas E. Nickelson ◽

Mario F. Solazzi ◽

Steven L. Johnson

Keyword(s):

Surface Area ◽

Coho Salmon ◽

Oncorhynchus Kisutch ◽

Early Time ◽

Wild Populations ◽

Pool Surface ◽

Coastal Streams

We evaluated the effectiveness of using hatchery coho salmon (Oncorhynchus kisutch) presmolts to rebuild wild populations in Oregon coastal streams. Juvenile and adult populations were monitored in 15 stocked and 15 unstocked streams from summer 1980 until summer 1985. During the summers following the planting of presmolts, the number of juveniles per square metre of pool surface area was higher in the stocked streams than in the unstocked streams. However, wild juveniles were significantly less abundant in the stocked streams during the 2 yr when density of wild juveniles was estimated separately from hatchery juveniles. Adult returns to the stocked streams were not significantly different from adult returns to the unstocked streams, but returns tended to be earlier in the stocked streams than in the unstocked streams. Despite similar numbers of adults per kilometre in the stocked streams and unstocked streams in the years the presmolts returned to spawn, the resulting densities of juveniles in the stocked streams were significantly lower than the densities of juveniles in the unstocked streams. We concluded that the early time of spawning of the hatchery coho salmon was largely responsible for their failure to rebuild the populations in the streams stocked with presmolts.

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Effects of Streamflow and Upwelling on Yield of Wild Coho Salmon (Oncorhynchus kisutch) in Oregon

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f81-066 ◽

1981 ◽

Vol 38 (4) ◽

pp. 471-475 ◽

Cited By ~ 29

Author(s):

Dennis L. Scarnecchia

Keyword(s):

Coho Salmon ◽

Oncorhynchus Kisutch ◽

Positive Relation ◽

Significant Relation ◽

Oregon Coast ◽

Growth And Survival ◽

Coastal Rivers ◽

High Flows ◽

Oceanic Upwelling

To investigate the dependence of coho salmon (Oncorhynchus kisutch) yield on streamflow and oceanic upwelling, I regressed catch by the Oregon commercial troll fishery from 1942 to 1962 against indices of offshore upwelling the previous spring and measurements of streamflow from five Oregon coastal rivers during the freshwater rearing phase. A highly significant positive relation was found between total streamflows during the freshwater residency of the fish for the five rivers combined and the weight of the annual catch of coho salmon from 1942 to 1962. There was also a significant positive relation between total combined annual (January–December) flows for these rivers and the catch 2 yr later. Conversely, I found no significant relation between the 60 consecutive days of lowest flow during summer and catch 2 yr later. High flows during freshwater rearing probably provide more habitat and better conditions for growth and survival. I also found a significant positive relation between April through June upwelling at two stations and catch of coho salmon the following year from 1947 to 1962. Fifty-six percent of the variation in catch from 1947 to 1962 was explained by the total flows during freshwater residency, 60 consecutive days of lowest flow, plus combined April through June upwelling at both stations. It is suggested that some stocks of coho salmon smolts may move southward or remain in local offshore waters after they enter the ocean to take advantage of the production of invertebrates resulting from upwelling.Key words: streamflow, upwelling, coho salmon, Oregon coast

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Effect of forecast skill on management of the Oregon coast coho salmon (Oncorhynchus kisutch) fishery

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f2012-040 ◽

2012 ◽

Vol 69 (6) ◽

pp. 1016-1032 ◽

Cited By ~ 5

Author(s):

David E. Rupp ◽

Thomas C. Wainwright ◽

Peter W. Lawson

Keyword(s):

Coho Salmon ◽

Oncorhynchus Kisutch ◽

Status Quo ◽

Forecast Skill ◽

Oregon Coast ◽

Performance Metric ◽

Specific Performance ◽

The Status ◽

Target Performance ◽

Fish Survival

Better fisheries management is often given as one justification for research on improving forecasts of fish survival. However, the value gained from expected improvements in forecast skill in terms of achieving management goals is rarely quantified as part of research objectives. Using Monte Carlo simulations of population dynamics, we assessed the effect of forecast skill under two strategies for managing Oregon coast natural (OCN) coho salmon ( Oncorhynchus kisutch ). The first, or status quo, strategy is currently being used to rebuild threatened OCN coho populations. This strategy determines harvest based on both a forecasted marine survival rate and parental spawner abundance. The second strategy relies on a forecast of preharvest adult abundance to achieve a constant spawner escapement target. Performance of the status quo strategy was largely insensitive to forecast skill, while the second strategy showed sensitivity that varied with escapement target and specific performance metric. The results imply that effort towards improving forecasts is not justifiable solely on the basis of improved management under the status quo strategy, though it may be were the management strategy altered.

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Potential benefits of a conservation hatchery program for supplementing Oregon coast coho salmon (Oncorhynchus kisutch) populations: a stochastic model investigation

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f05-080 ◽

2005 ◽

Vol 62 (8) ◽

pp. 1920-1935 ◽

Cited By ~ 10

Author(s):

Gretchen R Oosterhout ◽

Charles W Huntington ◽

Thomas E Nickelson ◽

Peter W Lawson

Keyword(s):

Habitat Restoration ◽

Coho Salmon ◽

Oncorhynchus Kisutch ◽

Solution Space ◽

Oregon Coast ◽

Hatchery Fish ◽

Natural Production ◽

Management Actions ◽

Genetic Risks ◽

Hatchery Program

This study developed a stochastic life cycle model to simulate idealized supplementation strategies to investigate the following question: under what circumstances could hatchery fish stocking contribute to the recovery of Oregon coast coho salmon (Oncorhynchus kisutch)? Simulations were used to find a solution space, defined by the attributes of wild and hatchery-bred salmon, their offspring, and their environments, where hatchery fish could supplement natural production without further depressing it until natural or human factors restricting production were relieved. These simulations suggest that short-duration, tightly controlled, low-intensity conservation hatchery programs designed to minimize genetic and ecological risks may yield minor short-term increases in adult coho salmon abundance while posing significant ecological and genetic risks. No solution space was found that indicated clear long-term benefits from such a supplementation program. Of all the management actions modeled, habitat restoration offered by far the largest and only permanent gains in coho salmon abundance while posing no genetic or ecological risk to the fish. The modeled benefits of habitat restoration were significant regardless of assumptions made about the fitness of hatchery fish and their offspring.

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Social interactions of coho salmon (Oncorhynchus kisutch) smolts in seawater

Canadian Journal of Zoology ◽

10.1139/z85-355 ◽

1985 ◽

Vol 63 (10) ◽

pp. 2401-2407 ◽

Cited By ~ 11

Author(s):

Cynthia A. Paszkowski ◽

Bori L. Olla

Keyword(s):

Social Behavior ◽

Social Interactions ◽

Social System ◽

Agonistic Behavior ◽

Coho Salmon ◽

Oncorhynchus Kisutch ◽

Distribution Patterns ◽

Oregon Coast ◽

Fish Hatchery ◽

Free Ranging

The behavior of coho salmon (Oncorhynchus kisutch) smolts was examined under laboratory conditions to determine if the hierarchical–territorial social system characteristic of this species in freshwater persisted in seawater. When held in groups of two to eight fish, hatchery-reared, accelerated underyearling smolts formed hierarchies controlled by a single dominant who was responsible for most of the observed movement, chases, and feeding. Agonistic behavior also occurred within pairs of recently smolted fingerlings from two hatchery stocks with different rearing histories and in groups containing free-ranging fish captured off the Oregon coast. Possible relationships between the observed social behavior and marine distribution patterns of juvenile coho salmon are discussed.

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Seasonal Changes in Habitat Use by Juvenile Coho Salmon (Oncorhynchus kisutch) in Oregon Coastal Streams

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f92-088 ◽

1992 ◽

Vol 49 (4) ◽

pp. 783-789 ◽

Cited By ~ 136

Author(s):

Thomas E. Nickelson ◽

Jeffrey D. Rodgers ◽

Steven L. Johnson ◽

Mario F. Solazzi

Keyword(s):

Habitat Use ◽

Seasonal Changes ◽

Coho Salmon ◽

Oncorhynchus Kisutch ◽

Beaver Pond ◽

Winter Habitat ◽

Oregon Coast ◽

Beaver Ponds ◽

Salmon Fry ◽

Coastal Streams

Habitat use by juvenile coho salmon (Oncorhynchus kisutch) during spring, summer, and winter was examined in Oregon coastal streams. Coho salmon fry were most abundant in backwater pools during spring. During summer, juvenile coho salmon were more abundant in pools of all types than they were in glides or riffles. During winter, juvenile coho salmon were most abundant in alcoves and beaver ponds. Because of the apparent strong preference for alcove and beaver pond habitat during winter and the rarity of that habitat in coastal streams, we concluded that if spawning escapement is adequate, the production of wild coho salmon smolts in most coho salmon spawning streams on the Oregon Coast is probably limited by the availability of adequate winter habitat.

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Applying time series models with spatial correlation to identify the scale of variation in habitat metrics related to threatened coho salmon (Oncorhynchus kisutch) in the Pacific Northwest

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f2012-096 ◽

2012 ◽

Vol 69 (11) ◽

pp. 1773-1782 ◽

Cited By ~ 6

Author(s):

Eric J. Ward ◽

George R. Pess ◽

Kara Anlauf-Dunn ◽

Chris E. Jordan

Keyword(s):

Time Series ◽

Spatial Correlation ◽

Pacific Northwest ◽

Coho Salmon ◽

Spatial Scales ◽

Oncorhynchus Kisutch ◽

Fine Sediment ◽

Environmental Stochasticity ◽

Observation Error ◽

Data Set

Trend analyses are common in the analysis of fisheries data, yet the majority of them ignore either observation error or spatial correlation. In this analysis, we applied a novel hierarchical Bayesian state-space time series model with spatial correlation to a 12-year data set of habitat variables related to coho salmon ( Oncorhynchus kisutch ) in coastal Oregon, USA. This model allowed us to estimate the degree of spatial correlation separately for each habitat variable and the importance of observation error relative to environmental stochasticity. This framework allows us to identify variables that would benefit from additional sampling and variables where sampling could be reduced. Of the eight variables included in our analysis, we found three metrics related to habitat quality correlated at large spatial scales (gradient, fine sediment, shade cover). Variables with higher observation error (pools, active channel width, fine sediment) could be made more precise with more repeat visits. Our spatio-temporal model is flexible and extendable to virtually any spatially explicit monitoring data set, even with large amounts of missing data and no repeated observations. Potential extensions include fisheries catch data, abiotic indicators, invasive species, or species of conservation concern.

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Landscape characteristics, land use, and coho salmon (Oncorhynchus kisutch) abundance, Snohomish River, Wash., U.S.A.

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f02-035 ◽

2002 ◽

Vol 59 (4) ◽

pp. 613-623 ◽

Cited By ~ 76

Author(s):

George R Pess ◽

David R Montgomery ◽

E Ashley Steel ◽

Robert E Bilby ◽

Blake E Feist ◽

...

Keyword(s):

Land Use ◽

Coho Salmon ◽

Oncorhynchus Kisutch ◽

Habitat Characteristics ◽

Land Use Patterns ◽

Landscape Characteristics ◽

Use Patterns ◽

Local Geology ◽

Annual Distribution ◽

Agricultural Areas

We used temporally consistent patterns in the spatial distribution of returning adult coho salmon (Oncorhynchus kisutch) to explore relationships between salmon abundance, landscape characteristics, and land use patterns in the Snohomish River watershed, Wash. The proportion of total adult coho salmon abundance supported by a specific stream reach was consistent among years, even though interannual adult coho salmon abundance varied substantially. Wetland occurrence, local geology, stream gradient, and land use were significantly correlated with adult coho salmon abundance. Median adult coho salmon densities in forest-dominated areas were 1.53.5 times the densities in rural, urban, and agricultural areas. Relationships between these habitat characteristics and adult coho salmon abundance were consistent over time. Spatially explicit statistical models that included these habitat variables explained almost half of the variation in the annual distribution of adult coho salmon. Our analysis indicates that such models can be used to identify and prioritize freshwater areas for protection and restoration.

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Effect of changing land use patterns on the distribution of coho salmon (Oncorhynchus kisutch) in the Puget Sound region

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f08-113 ◽

2008 ◽

Vol 65 (10) ◽

pp. 2138-2148 ◽

Cited By ~ 17

Author(s):

Robert E. Bilby ◽

Lauren A. Mollot

Keyword(s):

Land Use ◽

Forest Cover ◽

Coho Salmon ◽

Landsat Imagery ◽

Puget Sound ◽

Substantial Reduction ◽

Oncorhynchus Kisutch ◽

Urban Land Use ◽

Aerial Photographs ◽

Population Increase

Population increase in the Pacific Northwest of North America over the last century has led to the removal of forests for various purposes. Evidence of salmon response to these alterations in land use is rare owing to a scarcity of fish population data and a high degree of interannual variation in abundance. We examined the relationship between the spatial distribution of spawning coho salmon ( Oncorhynchus kisutch ) and changes in land use from 1984 through 2001 at 84 sites in four rivers draining into northern Puget Sound. Changes in land use over this period were determined from LandSat imagery, county zoning designations, and aerial photographs. Substantial reduction in forest cover occurred in many of the index watersheds during this time. The proportion of salmon using sites subjected to increased urban land use over the study period declined about 75%. Increases were observed at forested sites and those with increased rural residential use. Maintaining salmon populations in rapidly developing areas may require the identification and protection of sites that support large salmon populations and steering development to areas supporting few fish.

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