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.

Influence of parental stock and incubation temperature on the early development of coho salmon (Oncorhynchus kisutch) in British Columbia

1990 ◽  
Vol 68 (2) ◽  
pp. 347-358 ◽  
Author(s):  
C. B. Murray ◽  
T. D. Beacham ◽  
J. D. McPhail
Keyword(s):  
British Columbia ◽  
Coho Salmon ◽  
Incubation Temperature ◽  
Survival Rates ◽  
Oncorhynchus Kisutch ◽  
Queen Charlotte Islands ◽  
Hatching Time ◽  
Parental Stock ◽  
Queen Charlotte Island ◽  
Developmental Characteristics

Coho salmon (Oncorhynchus kisutch) stocks in British Columbia spawning from October to April were surveyed for variation in developmental characteristics at incubation temperatures from 1.5 to 15 °C. There were no trends in embryo or alevin survival rates associated with spawning time or spawning temperature. The highest embryo and alevin survival rates occurred at 4 or 5 °C and complete mortality generally occurred at 14 or 15 °C. Vancouver and Queen Charlotte Island stocks had lower survival rates at 1.5 and 2 °C than did mainland stocks. Time to 50% hatching and 50% emergence varied inversely with incubation temperature. Alevin hatching time for the Pallant Creek stock on the Queen Charlotte Islands was later than for all other stocks. Stocks had different trends in alevin and fry length and weight with respect to incubation temperature. Northern stocks tended to be more efficient than southern stocks at converting yolk to body tissue at 1.5 and 2 °C, as were mainland stocks compared with island stocks.

Declining patterns of Pacific Northwest steelhead trout (Oncorhynchus mykiss) adult abundance and smolt survival in the ocean

2017 ◽  
Vol 74 (8) ◽  
pp. 1275-1290 ◽  
Author(s):  
Neala W. Kendall ◽  
Gary W. Marston ◽  
Matthew M. Klungle
Keyword(s):  
British Columbia ◽  
Time Series ◽  
Oncorhynchus Mykiss ◽  
Pacific Northwest ◽  
State Space Model ◽  
Puget Sound ◽  
Survival Rates ◽  
Steelhead Trout ◽  
Factors Affecting ◽  
Adult Abundance

Examination of population abundance and survival trends over space and time can guide management and conservation actions with information about the spatial and temporal scale of factors affecting them. Here, we analyzed steelhead trout (anadromous Oncorhynchus mykiss) adult abundance time series from 35 coastal British Columbia and Washington populations along with smolt-to-adult return (smolt survival) time series from 48 populations from Washington, Oregon, and the Keogh River in British Columbia. Over 80% of the populations have declined in abundance since 1980. A multivariate autoregressive state-space model revealed smolt survival four groupings: Washington and Oregon coast, lower Columbia River, Strait of Juan de Fuca, and Puget Sound – Keogh River populations. Declines in smolt survival rates were seen for three of the four groupings. Puget Sound and Keogh River populations have experienced low rates since the early 1990s. Correlations between population pairs’ time series and distance apart illustrated that smolt survival rates were more positively correlated for proximate populations, suggesting that important processes, including those related to ocean survival, occur early in the marine life of steelhead.

Experiments on Oral Secretion of the Rocky Mountain Wood Tick, Dermacentor andersoni Stiles (Acarina: Ixodidae)

1957 ◽  
Vol 89 (1) ◽  
pp. 1-5 ◽  
Author(s):  
J. D. Gregson
Keyword(s):  
British Columbia ◽  
Pacific Northwest ◽  
Rocky Mountain ◽  
Dermacentor Variabilis ◽  
Oral Secretion ◽  
Amblyomma Maculatum ◽  
Dermacentor Andersoni ◽  
The Pacific ◽  
Tick Paralysis ◽  
Rocky Mountain Wood Tick

Tick paralysis continues to be one of the most baffling and fascinating tickborne diseases in Canada. It was first reported in this country by Todd in 1912. Since then about 250 human cases, including 28 deaths, have been recorded from British Columbia. Outbreaks in cattle have affected up to 400 animals at a time, with losses in a herd as high as 65 head. Although the disease is most common in the Pacific northwest, where it is caused by the Rocky Mountain wood tick, Dermacentor andersoni Stiles, it has lately been reported as far south as Florida and has been produced by Dermacentor variabilis Say, Amblyomma maculatum Koch, and A. americanum (L.) (Gregson, 1953). The symptoms include a gradual ascending symmetrical flaccid paralysis. Apparently only man, sheep, cattle, dogs, and buffalo (one known instance) are susceptible, but even these may not necessarily be paralysed.

scholarly journals Evaluating Coexistence of Fish Species with Coastal Cutthroat Trout in Low Order Streams of Western Oregon and Washington, USA

Fishes ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 4
Author(s):  
Kyle D. Martens ◽  
Jason Dunham
Keyword(s):  
Pacific Northwest ◽  
Species Interactions ◽  
Coho Salmon ◽  
Cutthroat Trout ◽  
Single Species ◽  
The Pacific ◽  
Small Streams ◽  
Coastal Cutthroat Trout ◽  
Multiple Species ◽  
Low Order

When multiple species of fish coexist there are a host of potential ways through which they may interact, yet there is often a strong focus on studies of single species without considering these interactions. For example, many studies of forestry–stream interactions in the Pacific Northwest have focused solely on the most prevalent species: Coastal cutthroat trout. To examine the potential for interactions of other fishes with coastal cutthroat trout, we conducted an analysis of 281 sites in low order streams located on Washington’s Olympic Peninsula and along the central Oregon coast. Coastal cutthroat trout and juvenile coho salmon were the most commonly found salmonid species within these streams and exhibited positive associations with each other for both presence and density. Steelhead were negatively associated with the presence of coastal cutthroat trout as well as with coho salmon and sculpins (Cottidae). Coastal cutthroat trout most frequently shared streams with juvenile coho salmon. For densities of these co-occurring species, associations between these two species were relatively weak compared to the strong influences of physical stream conditions (size and gradient), suggesting that physical conditions may have more of an influence on density than species interactions. Collectively, our analysis, along with a review of findings from prior field and laboratory studies, suggests that the net effect of interactions between coastal cutthroat trout and coho salmon do not appear to inhibit their presence or densities in small streams along the Pacific Northwest.

1999 Pacific Northwest Labor History Association Conference

2000 ◽  
Vol 57 ◽  
pp. 117-119 ◽  
Author(s):  
Daniel Jacoby
Keyword(s):  
British Columbia ◽  
Pacific Northwest ◽  
Labor History ◽  
Definitive Answer ◽  
Preferable Alternative ◽  
The Pacific ◽  
The Moment ◽  
Academic Conferences

I cannot provide a definitive answer to those of us pondering what the best alternative to capitalism is, but after attending the Pacific Northwest Labor History Association (PNLHA) Conference in Westminster, British Columbia, over the weekend of May 28–30, 1999, I can tell you that this is certainly a preferable alternative to standard academic conferences. As usual, the PNLHA was able to produce a cadre of historians (from the trades as well as academia), active unionists, and old-timers whose memories are as tapable as a keg of beer. Although the association designates labor history as its subject, newly elected President Ross Rieder likes to say, “History ends the moment before now.”

scholarly journals Evidence for Freshwater Residualism in Coho Salmon, Oncorhynchus kisutch, From a Watershed on the North Coast of British Columbia

2017 ◽  
Vol 130 (4) ◽  
pp. 336 ◽  
Author(s):  
Eric A Parkinson ◽  
Chris J Perrin ◽  
Daniel Ramos-Espinoza ◽  
Eric B Taylor
Keyword(s):  
British Columbia ◽  
Fresh Water ◽  
Coho Salmon ◽  
Pacific Salmon ◽  
Oncorhynchus Kisutch ◽  
Water Levels ◽  
North Coast ◽  
The North ◽  
Seaward Migration ◽  
Mature Fish

The Coho Salmon, Oncorhynchus kisutch, is one of seven species of Pacific salmon and trout native to northeastern Pacific Ocean watersheds. The species is typically anadromous; adults reproduce in fresh water where juveniles reside for 1–2 years before seaward migration after which the majority of growth occurs in the ocean before maturation at 2–4 years old when adults return to fresh water to spawn. Here, we report maturation of Coho Salmon in two freshwater lakes on the north coast of British Columbia apparently without their being to sea. A total of 15 mature fish (11 males and four females) were collected in two lakes across two years. The mature fish were all at least 29 cm in total length and ranged in age from three to five years old. The occurrence of Coho Salmon that have matured in fresh water without first going to sea is exceedingly rare in their natural range, especially for females. Such mature Coho Salmon may represent residual and distinct breeding populations from those in adjacent streams. Alternatively, they may result from the ephemeral restriction in the opportunity to migrate seaward owing to low water levels in the spring when Coho Salmon typically migrate to sea after 1–2 years in fresh water. Regardless of their origin, the ability to mature in fresh water without seaward migration may represent important adaptive life history plasticity in response to variable environments.

Evidence of chemically mediated population recognition in coho salmon (Oncorhynchus kisutch)

1986 ◽  
Vol 64 (1) ◽  
pp. 84-87 ◽  
Author(s):  
Thomas P. Quinn ◽  
Graeme M. Tolson
Keyword(s):  
British Columbia ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
The Other ◽  
Potential Source ◽  
Source Of Information

To test the hypothesis that population-specific pheromones guide adult salmonids to their natal streams, juvenile and adult coho salmon (Oncorhynchus kisutch) were tested for chemosensory responses in two-choice tanks. Coho salmon from Quinsam and Big Qualicum rivers, British Columbia, Canada, distinguished their own population from the other. Tagging evidence indicates that straying between these two rivers and a third, geographically intermediate river seldom occurs. Thus, population-specific chemicals constitute a potential source of information for homing coho salmon, though their role vis-à-vis imprinted odors from other sources could not be evaluated.

Notes on Parathion-Resistant Strains of Two Phytophagous Mites and a Predacious Mite in British Columbia

1958 ◽  
Vol 90 (2) ◽  
pp. 92-97 ◽  
Author(s):  
C. V. G. Morgan ◽  
N. H. Anderson
Keyword(s):  
British Columbia ◽  
Pacific Northwest ◽  
Predacious Mites ◽  
Predacious Mite ◽  
Phytophagous Mites ◽  
European Red Mite ◽  
The Pacific ◽  
Resistant Strains ◽  
Tetranychus Pacificus

The existence of strains of mites resistant to parathion has been well established (Garman, 1950; Lienk, Dean, & Chapman, 1952; Newcomer & Dean, 1952; Smith & Fulton, 1951). Resistant strains of the European red mite, Metatetranychus ulmi (Koch), first occurred in orchards of the Pacific northwest in 1950 (Newcomer, 1951; O'Neill & Hantsbarger, 1951), approximately three years after parathion was first used as an acaricide. Two other species of orchard mites, the Pacific mite, Tetranychus pacificus McG., and T. mcdanieli McG., were subsequently reported to have developed parathion-resistant strains in the same area (Newcomer & Dean, 1953). Though parathion is lethal to most predacious mites and insects, Huffaker and Kennett (1953) found a difference in tolerance between species of Typhlodromus in the field and in the laboratory: T. reticulatus Oudms. was very susceptible to parathion whereas T. occidentalis Nesbitt was not appreciably affected by it.

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.

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