Environmental factors influencing freshwater survival and smolt production in Pacific Northwest coho salmon (Oncorhynchus kisutch)

2004 ◽  
Vol 61 (3) ◽  
pp. 360-373 ◽  
Author(s):  
P W Lawson ◽  
E A Logerwell ◽  
N J Mantua ◽  
R C Francis ◽  
V N Agostini
Keyword(s):  
Pacific Northwest ◽  
Air Temperature ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Stream Flows ◽  
Factors Influencing ◽  
Life Phase ◽  
Air Temperatures ◽  
Queets River ◽  
Marine Survival

Climate variability is well known to affect the marine survival of coho salmon (Oncorhynchus kisutch) in Oregon and Washington. Marine factors have been used to explain up to 83% of the variability in Oregon coastal natural coho salmon recruitment, yet about half the variability in coho salmon recruitment comes from the freshwater life phase of the life cycle. This seeming paradox could be resolved if freshwater variability were linked to climate and climate factors influencing marine survival were correlated with those affecting freshwater survival. Effects of climate on broad-scale fluctuations in freshwater survival or production are not well known. We examined the influence of seasonal stream flows and air temperature on freshwater survival and production of two stock units: Oregon coastal natural coho salmon and Queets River coho salmon from the Washington Coast. Annual air temperatures and second winter flows correlated strongly with smolt production from both stock units. Additional correlates for the Oregon Coast stocks were the date of first fall freshets and flow during smolt outmigration. Air temperature is correlated with sea surface temperature and timing of the spring transition so that good freshwater conditions are typically associated with good marine conditions.

Importance of Smolt Size and Early Ocean Growth to Interannual Variability in Marine Survival of Coho Salmon (Oncorhynchus kisutch)

1990 ◽  
Vol 47 (11) ◽  
pp. 2181-2194 ◽  
Author(s):  
L. Blair Holtby ◽  
Bruce C. Andersen ◽  
Ronald K. Kadowaki
Keyword(s):  
Interannual Variability ◽  
Coho Salmon ◽  
Age Groups ◽  
Oncorhynchus Kisutch ◽  
Northwest Coast ◽  
Size Distributions ◽  
Strongly Correlated ◽  
Large Size ◽  
Ocean Conditions ◽  
Marine Survival

The importance of smolt size and early ocean growth to the marine survival of coho salmon was examined over a 17-yr period at Carnation Creek, British Columbia. Comparisons of overall marine survival were made both between-years, using two smolt age-groups of different mean sizes, and within-years using observed smolt size distributions and smolt size distributions back-calculated from the scales of returning adults. Large size did not confer a consistent survival advantage but large smolts did survive better in years when marine survival was relatively poor. Marine survivals were strongly correlated with early ocean growth as estimated by the spacing of the first five ocean circuli on the scales of returning adults. Marine survival and early ocean growth were positively correlated with ocean conditions indicative of strong upwelling along the northwest coast of Vancouver Island. Neither smolt survival nor early ocean growth were correlated with regional coho smolt production. Our observations suggest that interannual variability in smolt survival was being driven by ocean conditions that determined smolt growth rates which subsequently affected the susceptibility of smolts to a size-selective predator.

Building an ecosystem model using mismatched and fragmented data: A probabilistic network of early marine survival for coho salmon Oncorhynchus kisutch in the Strait of Georgia

2013 ◽  
Vol 115 ◽  
pp. 41-52 ◽  
Author(s):  
H. Andres Araujo ◽  
Carrie Holt ◽  
Janelle M.R. Curtis ◽  
R.I. Perry ◽  
James R. Irvine ◽  
...  
Keyword(s):  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Ecosystem Model ◽  
Strait Of Georgia ◽  
Probabilistic Network ◽  
Marine Survival ◽  
Fragmented Data

Decadal Climate Variation and Coho Salmon Catch

2003 ◽  
Author(s):  
David Greenland
Keyword(s):  
Pacific Northwest ◽  
Coho Salmon ◽  
Juvenile Fish ◽  
Early Summer ◽  
Air Temperatures ◽  
Ecological Changes ◽  
The Pacific ◽  
Freshwater Stream ◽  
Long Term Ecological Research ◽  
Decadal Climate

When temporally smoothed data are used for the period 1925 to 1985 there is a close inverse statistical relationship acting at an interdecadal timescale between the Pacific Northwest (PNW) air temperatures and Coho salmon catch off the coast of Washington and Oregon. This relationship is now well known, although not fully explained, but at the time of its discovery in 1994 it was part of advances being made by several research groups on interdecadal-scale climate/ecological changes in the PNW (Greenland 1995). The discovery and later, related findings may be usefully examined within the context of the framework questions of this book (see chapter 1) because it provides a very interesting example of climate variability and ecosystem response found, in part, by Long-Term Ecological Research (LTER) investigators. The logical progression for this chapter is first to review a little of the relationship between Coho salmon and climate and then to explain how a study at one LTER site led to a finding with regional implications. An update of the findings at interdecadal-scale climate/ecological changes in the PNW is then appropriate, followed by a discussion of the topic with the framework questions of this book. The PNW is defined, for the purposes of this chapter, as the area of Washington and Oregon west of the crest of the Cascade Range. The term decadal is used loosely in this chapter to refer to changes that focus on time periods of about 10 to 30 years in length. Salmon live part of their lives in terrestrial, freshwater environments and part in marine, saltwater environments. The salmon life history starts with fertilized eggs remaining in gravel in freshwater stream beds and hatching after 1–3 months. One to five months later, fry emerge in the spring or summer. Juvenile fish are in freshwater from a few days to 4 years, depending on species and locality. After the juveniles change to smolts, they can migrate to the ocean, usually in spring or early summer, often taking advantage of streamflows driven by snowmelt. The fish spend 1–4 years in the ocean and then return to their freshwater home stream to spawn and die. More specifically, the typical life cycle for Oregon Coho spans 3 years (18 months in freshwater and 18 months in the ocean).

Reference points for coho salmon (Oncorhynchus kisutch) harvest rates and escapement goals based on freshwater production

2000 ◽  
Vol 57 (4) ◽  
pp. 677-686 ◽  
Author(s):  
Michael J Bradford ◽  
Ransom A Myers ◽  
James R Irvine
Keyword(s):  
Reference Point ◽  
Historical Data ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Reference Points ◽  
Data Sets ◽  
Ocean Productivity ◽  
Freshwater Habitats ◽  
Marine Survival ◽  
Stick Model

We describe a simple scheme for the management of coho salmon (Oncorhynchus kisutch) population aggregates that uses reference points derived from an empirical analysis of freshwater production data. We fit a rectilinear "hockey stick" model to 14 historical data sets of female spawner abundance and resulting smolt production and found that at low spawner abundance, the average productivity was about 85 smolts per female spawner. Variation in productivity among streams may be related to the quality of the stream habitat. We show how freshwater productivity can be combined with forecasts of marine survival to provide a limit reference point harvest rate. Our method will permit harvest rates to track changes in ocean productivity. We also used the historical data to estimate that, on average, a density of 19 female spawners·km-1 is required to fully seed freshwater habitats with juveniles. However, there was considerable variation among the streams that might limit the utility of this measure as a reference point. Uncertainty in the forecasts of marine survival and other parameters needs to be incorporated into our scheme before it can be considered a precautionary approach.

Influences of Upwelling, Ocean Temperature, and Smolt Abundance on Marine Survival of Coho Salmon (Oncorhynchus kisutch) in the Oregon Production Area

1986 ◽  
Vol 43 (3) ◽  
pp. 527-535 ◽  
Author(s):  
Thomas E. Nickelson
Keyword(s):  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
High Survival ◽  
Ocean Temperature ◽  
Related Factors ◽  
Public And Private ◽  
Adult Relationships ◽  
Significant Relationships ◽  
Production Area ◽  
Marine Survival

The relationships between the marine survival of hatchery and wild coho salmon (Oncorhynchus kisutch) in the Oregon Production Area and ocean upwelling, ocean temperature, and smolt abundance were investigated. Hatchery coho appear to be more sensitive than wild coho to changes in upwelling-related factors although this difference may be due to errors in the estimates of wild smolts and adults that were used in the analysis. Two levels of upwelling (strong and weak), which are associated with a twofold difference in survival of hatchery coho smolts, were identified. Significant relationships were identified between survival of hatchery smolts and survival of wild smolts that migrated in strong upwelling years and sea-surface temperature during that year. Similar relationships were not as apparent for smolts migrating in weak upwelling years as they were for smolts migrating in strong upwelling years. Each major component of coho production (wild, public hatchery, and private hatchery), when treated separately, as well as public and private hatchery coho combined, exhibited linear smolt-to-adult relationships. Only hatchery plus wild coho that migrated in weak upwelling years and hatchery plus wild coho in all years combined exhibited nonlinear smolt-to-adult relationships. I concluded that these nonlinear relationships were caused by a shift in the stock composition of the Oregon Production Area coho population from predominantly high-survival, wild fish when smolt numbers were low to predominantly low-survival, hatchery fish when smolt numbers were high.

Survival, Ocean Growth, and Ocean Distribution of Differentially Timed Releases of Hatchery Coho Salmon (Oncorhynchus kisutch)

1989 ◽  
Vol 46 (7) ◽  
pp. 1216-1226 ◽  
Author(s):  
Stephen B. Mathews ◽  
Yukimasa Ishida
Keyword(s):  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Adult Survivors ◽  
Small Fish ◽  
Large Fish ◽  
Release Date ◽  
Marine Life ◽  
Coos Bay ◽  
The Mean ◽  
Marine Survival

Estimates of growth rates in early ocean life and length frequency distributions at time of release for adult survivors were inferred from scale measurements for lots of coho salmon (Oncorhynchus kisutch) released at several dates from a Columbia River hatchery (Big Creek) and a southern Oregon hatchery (Coos Bay). Analysis of these measurements failed to support either of two literature-suggested hypotheses for the variability of marine survival of hatchery coho by date of release: (1) intraseasonal variability of food supply during early marine life; and (2) intraseasonally improving ability of smaller individuals within release lots to convert to salt water. Marine survival improved substantially with date of release at both hatcheries. However, fish released earliest, which survived relatively poorly, grew as fast in early marine life as fish released later, which survived better. Thus, poor survival of the early released fish did not appear related to lack of food at early ocean life. For the Big Creek hatchery, no significant differences were seen between the mean lengths at date of release and the mean release-date lengths of adult survivors back calculated from their scales, for lots released on May 5, June 3, and July 2. Apparently, small and large fish of each lot survived with equal probability. For the Coos Bay hatchery, the mean release-date lengths of adult survivors were significantly larger than the mean lengths of all fish released, for each of six lots released between early June and late July. Thus, large fish apparently survived better than small ones within each of these six lots. But there was no seasonal trend in survivability of small fish relative to large ones, contrary to hypothesis (2)

Spatial and temporal factors affecting survival in coho salmon (Oncorhynchus kisutch) in the Pacific Northwest

1998 ◽  
Vol 55 (9) ◽  
pp. 2067-2077 ◽  
Author(s):  
Claribel Coronado ◽  
Ray Hilborn
Keyword(s):  
British Columbia ◽  
Pacific Northwest ◽  
Coho Salmon ◽  
Survival Rates ◽  
Oncorhynchus Kisutch ◽  
Dominant Factor ◽  
Spatial And Temporal Patterns ◽  
Factors Affecting ◽  
The Pacific ◽  
Ocean Conditions

Survival rates for coho salmon (Oncorhynchus kisutch) were estimated for all coded wire tag release groups in the Pacific Northwest between 1971 and 1990. The spatial and temporal patterns show considerable geographic variation, with most regions south of northern British Columbia showing declining survival since 1983, while northern areas have shown increasing survival during that period. The number of years of operation explained very little of the variation in survival, and many hatcheries showed major increases in survival after several years of operation. Survival of marked wild fish generally showed the same trend as hatchery fish. We conclude that the dominant factor affecting coho salmon survival since the 1970s is ocean conditions and that there are major geographic differences in the pattern of ocean conditions. The decline in survival seen in British Columbia and south over the last decade suggests that a major reduction in exploitation rates is necessary to maintain the populations.

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

2012 ◽  
Vol 69 (11) ◽  
pp. 1773-1782 ◽  
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.

Stress Responses to Transportation and Fitness for Marine Survival in Coho Salmon (Oncorhynchus kisutch) Smolts

1980 ◽  
Vol 37 (5) ◽  
pp. 765-769 ◽  
Author(s):  
J. L. Specker ◽  
C. B. Schreck
Keyword(s):  
Kidney Disease ◽  
Atpase Activity ◽  
Stress Responses ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Control Fish ◽  
Performance Capacity ◽  
Bacterial Kidney Disease ◽  
Marine Survival

Smolting coho salmon (Oncorhynchus kisutch) were transported experimentally at low and high densities (12 and 120 g/L) for short and long periods (4 and 12 h). Because smolts can be transplanted directly to seawater, half of the fish in each treatment were transported to tanks containing seawater and half to tanks containing freshwater. Plasma corticosteroids and glucose were elevated at unloading in all groups, and corticosteroids were still above the resting level 24 h later. Potential smoltification indicators such as plasma thyroxin concentration and gill (Na+/K+)–ATPase activity were not affected by transportation. Increased corticosteroids were correlated to increased mortality in transported salmon compared to acclimated control fish when subjected to a bioassay of stress — severe confinement. The various transport regimens did not cause increased expression of latent bacterial kidney disease. In a further experiment, smolting coho salmon were released into a stream after transport for different durations. The number of fish migrating on the 1st d appeared to be inversely related to the degree of "stress" en route, but the movements of all groups were similar thereafter. We concluded that transportation caused stress in the fish regardless of hauling regimen; that increased corticosteroids may have potential as indicators of reduced performance capacity; that the greatest stress occurred during loading and the first few hours en route; and that transported smolting coho salmon seem to be equally fit for entry into freshwater or seawater.Key words: coho salmon, stress, transportation, seawater entry, corticosteroids

Seaward Movement of Coho Salmon (Oncorhynchus kisutch) Fry in Carnation Creek, an Unstable Coastal Stream in British Colombia

1982 ◽  
Vol 39 (4) ◽  
pp. 588-597 ◽  
Author(s):  
G. F. Hartman ◽  
B. C. Andersen ◽  
J. C. Scrivener
Keyword(s):  
Social Behavior ◽  
Coho Salmon ◽  
Rapid Development ◽  
Oncorhynchus Kisutch ◽  
Air Temperatures ◽  
Time Period ◽  
Main Period ◽  
British Colombia ◽  
Downstream Movement

The seaward movement of coho (Oncorhynchus kisutch) fry was monitored over a 10-yr period as a part of a major watershed study. The time period over which downstream movement took place varied widely during different years of study. Coho fry moved seaward earlier, and terminated the main period of movement earlier, following winters in which stream temperatures were warmer. It is presumed that they underwent more rapid development during winters in which stream temperatures were relatively high. Winter stream temperatures were primarily dependent on air temperatures. During seaward movement daily numbers fluctuated widely. Peaks of movement were coincident with or slightly before freshet peaks. In 94 of 122 cases (77%) the number of fry moving seaward during the night of peak discharge, or during the night before, was higher than in any of the three preceding nights. Movement in these cases may have been initiated by rainfall or falling water temperature or a combination of both. Aggressive behavior among coho fry is considered to be an underlying cause of seaward movement. In Carnation Creek, particularly in the early part of the period of seaward movement, the effects of such social behavior on movement patterns may be masked by the effect of freshets and related conditions. By autumn the number of fry remaining in the stream ranged from 9000 to 13 000 over the 10-yr study. Much of the downward adjustment to this resident fry population size occurred after the most active period of seaward movement.Key words: coho fry, social behavior, seaward movement, stream ecology, coho management

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