Quantifying survival of age-2 Chilko Lake sockeye salmon during the first 50 days of migration

We used acoustic telemetry to investigate survival of age-2 sockeye salmon (Oncorhynchus nerka) as they emigrated from Chilko Lake, British Columbia, Canada, to northeastern Vancouver Island (NEVI) from 2010 to 2014. We built on our previously reported results by including an additional year of data and by converting survival estimates into rates (distance and time) to compare across disproportionate habitats. We also refined our survival estimates by including individual covariates in our survival models and by re-investigating the detection efficiency of the final detection site. There was a tag burden effect in 2012 and a body size effect in 2013. Excluding 2010, survival during the 35- to 47-day migration to NEVI (range of annual mean travel time; 1044 km) ranged between 8% and 14%. Weekly survival rate (S·week−1) during downstream migration to the Fraser River estuary, through the central Strait of Georgia (CSOG), and NEVI was 25%–46%, 75%–90%, and 34%–64%, respectively. In addition to marked losses in freshwater tributaries, sockeye also experienced high losses north of the CSOG consistent with earlier results for Cultus Lake sockeye.

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Migratory patterns of sockeye salmon (Oncorhynchus nerka) smolts in the Strait of Georgia, British Columbia, as determined by analysis of parasite assemblages

Canadian Journal of Zoology ◽

10.1139/z89-240 ◽

1989 ◽

Vol 67 (7) ◽

pp. 1670-1678 ◽

Cited By ~ 20

Author(s):

C. Groot ◽

R. E. Bailey ◽

L. Margolis ◽

K. Cooke

Keyword(s):

Sockeye Salmon ◽

River Estuary ◽

River System ◽

Fraser River ◽

Strait Of Georgia ◽

The Pacific ◽

Lake Washington ◽

Migratory Routes ◽

Migratory Patterns ◽

Parasite Assemblages

Sockeye salmon smolts from the Fraser River system, migrating northward through the Strait of Georgia towards the Pacific Ocean, follow either an eastern route by immediately travelling northward upon leaving the Fraser River estuary or a western route by first crossing the Strait of Georgia towards Vancouver Island and then moving northward diagonally across the Strait of Georgia to join smolts migrating along the mainland shore. We used variations in parasite assemblages among Fraser River and Lake Washington sockeye smolt stocks and a maximum-likelihood mixture model to estimate the stock composition of the smolts along the two migratory routes. The results showed that most Fraser River sockeye smolts migrate northward via both the eastern and western routes through the Strait of Georgia, indicating that there is no stock specific route selection. Lake Washington smolts were more prevalent along the western route and we suggest that these smolts are transported westward when attempting to cross the Fraser River plume.

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Pollution in the Strait of Georgia: a Review

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f83-132 ◽

1983 ◽

Vol 40 (7) ◽

pp. 1142-1167 ◽

Cited By ~ 8

Author(s):

Michael Waldichuk

Keyword(s):

Urban Communities ◽

Sewage Treatment ◽

Sewage Treatment Plant ◽

Treatment Plant ◽

River Estuary ◽

Oxygen Depletion ◽

Fraser River ◽

Pulp Mills ◽

Strait Of Georgia ◽

Spring Freshet

The Strait of Georgia, when considered as a whole, is still comparatively free of major pollution problems. Local environmental degradation has taken place, however, in waters on the periphery of the Strait, adjacent to urban communities and industries, such as pulp mills. The Fraser River, which is the major source of freshwater to the Strait, introduces natural and man-made materials that can adversely affect its estuary and the marine environment. The Strait of Georgia is flushed regularly, with deep waters being replaced about annually and waters in the upper layer having a considerably shorter residence time. Buildup of pollutants or their effects, e.g. oxygen depletion, are prevented in this way. However, there is refluxing of surface waters into the deep zone from the mixing region at the southern entrance to the Strait, and this means that surface pollutants such as oil could pollute the deep water and be retained there for up to a year. Problems affecting fisheries have been identified at the Fraser River Estuary arising from discharge of sewage treatment plant effluent. The major problem of pollution affecting fisheries in the Strait of Georgia has been bacteriological contamination from sewage, which has necessitated the closure of shellfish beds. The quality of oysters, as represented by condition factor and flavor, has deteriorated in the vicinity of some pulp mills. Evidence so far indicates that the "critical pollutants," e.g. petroleum hydrocarbons, organochlorines, and metals, which are persistent, toxic, and can be bioaccumulated by marine organisms, are present in low concentrations in the water, sediments, and biota away from the Fraser River Estuary. Wood wastes in the Strait of Georgia create a menace to navigation, especially during the spring freshet of the Fraser River.

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Estimating Stock Composition of Migrating Juvenile Fraser River (British Columbia) Sockeye Salmon, Oncorhynchus nerka, Using Parasites as Natural Tags

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f88-071 ◽

1988 ◽

Vol 45 (4) ◽

pp. 586-591 ◽

Cited By ~ 15

Author(s):

R. E. Bailey ◽

L. Margolis ◽

C. Groot

Keyword(s):

British Columbia ◽

Maximum Likelihood ◽

Sockeye Salmon ◽

Oncorhynchus Nerka ◽

Fraser River ◽

Dominant Group ◽

Strait Of Georgia ◽

Natural Tags ◽

Lake Washington ◽

The Individual

Simulated mixtures of juvenile sockeye salmon (Oncorhynchus nerka) were constructed using parasite data to represent proportionally the major component stocks of Fraser River and Lake Washington sockeye migrating within the Strait of Georgia, British Columbia, in 1982–84. Samples of migrating juveniles were also collected from Bedwell Harbour, South Pender Island, British Columbia, each year and analyzed for parasites and stock composition. The compositions of simulated and sample mixtures were estimated using a maximum likelihood stock composition model. Simulated mixture compositions were accurately estimated for most stocks for all year-classes. When significant misassignment occurred between stocks, the stocks were analyzed as a complex using the allocate-sum procedure. Sample mixture estimates correctly identified the dominant stock for each year-class, although for 1984 the dominant group was determined as a complex of three stocks because the individual stocks were not distinguishable. The results indicate that it is feasible to use parasites as natural tags to estimate stock compositions of migrating juvenile sockeye salmon in the Strait of Georgia.

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Drift Bottle Observations in the Strait of Georgia

Journal of the Fisheries Research Board of Canada ◽

10.1139/f58-057 ◽

1958 ◽

Vol 15 (5) ◽

pp. 1065-1102 ◽

Cited By ~ 7

Author(s):

Michael Waldichuk

Keyword(s):

Surface Water ◽

River Estuary ◽

Surface Current ◽

Fraser River ◽

Strait Of Georgia ◽

Average Speed ◽

Local Areas ◽

Strong Surface ◽

Gulf Islands ◽

Western Side

Drift bottle observations were carried out in the Strait of Georgia during the summers of 1926–1929. A total of 1,636 bottles was released of which 672 were recovered, giving an over-all return of 41%.No consistent pattern of drift in the strait as a whole could be clearly drawn from the recoveries. Some consistency of circulation in local areas can be inferred from the net drift of bottles.Winds dominated drift bottle movements in the open strait, where tidal currents are weak. A general northwestward drift was noted from releases along the eastern side of the strait and a southeastward drift along the western side. This suggests a large counterclockwise circulation of surface water over the whole strait. A smaller gyral circulating in the same direction is apparent in the southern strait, south of a line from Sand Heads to Active Pass.A strong surface current is directed from the Fraser River estuary across the strait to the passes among the Gulf Islands. This seaward flow of fresh water is augmented by a strong seaward tidal current during large ebb tides.Tidal currents are strong with definite periodicities in the channels bordering the strait. Current speeds of more than 26 cm./sec. (0.5 knot) were calculated from data on drift bottles whose drift was of brief duration. Average speed of drift was about 10 cm./sec. (0.2 knot).

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Infectious agents and gene expression differ between sockeye salmon (Oncorhynchus nerka) smolt age classes but do not predict migration survival

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2019-0113 ◽

2020 ◽

Vol 77 (3) ◽

pp. 484-495

Author(s):

Christine F. Stevenson ◽

Arthur L. Bass ◽

Nathan B. Furey ◽

Kristina M. Miller ◽

Shaorong Li ◽

...

Keyword(s):

Gene Expression ◽

Acoustic Telemetry ◽

Sockeye Salmon ◽

Infectious Agent ◽

Downstream Migration ◽

Infectious Agents ◽

Host Gene Expression ◽

Age Classes ◽

Molecular Assays ◽

Smolt Age

In some salmonid populations, multiple smolt age classes co-emigrate owing to variation in the duration of freshwater residence. While it is assumed that smolts prolong freshwater residence to maximize survival, infectious agent profiles and host gene expression (GE) have not been compared between concurrently migrating age classes. We coupled molecular assays of gill samples from nonlethally biopsied Chilko Lake sockeye salmon smolts with acoustic telemetry to study variation in infectious agent profiles and GE between age classes and survival groups. Although neither infectious agent profiles or GE were associated with survival, age-2 smolts exhibited higher mortality in the first 14 km of the downstream migration. There were measurable differences between the age classes in GE and the prevalence and load of “Candidatus Branchiomonas cysticola”, a bacterium commonly found in British Columbia salmonids. Relative to age-1 smolts, age-2 smolts displayed elevated GE related to inflammation and a molecular-based mortality-related signature. Although not associated with migration failure in this study, these patterns of GE are suggestive of mortality and could have implications for smolt survival.

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Anomalous Occurrence of Carp (Cyprinus carpio) in the Marine Environment

Journal of the Fisheries Research Board of Canada ◽

10.1139/f71-206 ◽

1971 ◽

Vol 28 (9) ◽

pp. 1345-1347 ◽

Cited By ~ 2

Author(s):

W. E. Barraclough ◽

D. G. Robinson

Keyword(s):

British Columbia ◽

Marine Environment ◽

Surface Waters ◽

Cyprinus Carpio ◽

River Estuary ◽

Vancouver Island ◽

Fraser River ◽

Strait Of Georgia ◽

Low Salinity ◽

Carp Cyprinus Carpio

Juvenile carp (Cyprinus carpio) were caught with a surface trawl in low salinity surface waters of the Strait of Georgia, British Columbia, during July 1967. A natural environmental route is established for the possible movement of carp from the Fraser River estuary to watersheds on Vancouver Island.

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Mercury Content of Spiny Dogfish (Squalus acanthias) in the Strait of Georgia, British Columbia

Journal of the Fisheries Research Board of Canada ◽

10.1139/f72-231 ◽

1972 ◽

Vol 29 (10) ◽

pp. 1487-1490 ◽

Cited By ~ 46

Author(s):

C. R. Forrester ◽

K. S. Ketchen ◽

C. C. Wong

Keyword(s):

Total Mercury ◽

River Estuary ◽

Mercury Content ◽

Squalus Acanthias ◽

Spiny Dogfish ◽

Fraser River ◽

Female Fish ◽

Male And Female ◽

Strait Of Georgia ◽

Total Length

Total mercury content of Squalus acanthias sampled in the Strait of Georgia reached levels of 0.5 ppm at fish lengths of 72 and 77 cm for male and female fish, respectively. For any given length above 65 cm the mercury content was higher among males than females and higher in samples taken off the Fraser River Estuary than in other areas of the Strait. Levels of mercury reached 1.7 ppm in males (to 95 cm in total length) and almost 2.0 ppm in females (to 120 cm in total length).

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Early marine growth of juvenile Fraser River sockeye salmon (Oncorhynchus nerka) in relation to juvenile pink (Oncorhynchus gorbuscha) and sockeye salmon abundance

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f2012-078 ◽

2012 ◽

Vol 69 (9) ◽

pp. 1499-1512 ◽

Cited By ~ 7

Author(s):

Skip McKinnell ◽

Maxine Reichardt

Keyword(s):

Sockeye Salmon ◽

Oncorhynchus Nerka ◽

Pink Salmon ◽

Oncorhynchus Gorbuscha ◽

First Year ◽

Fraser River ◽

Pink Salmon Oncorhynchus Gorbuscha ◽

Strait Of Georgia ◽

Average Survival

Mortality of salmon in the ocean is considered to be greatest during the first few months and that its magnitude is an inverse of growth. First year marine growth (M1) in two Fraser River sockeye salmon ( Oncorhynchus nerka ) populations was positively correlated, reflecting a shared oceanic experience as postsmolts. M1 declined abruptly in both populations after 1977, corresponding to a well-documented change in climate. The reduction in average M1 was not accompanied by a detectable reduction in average survival. In both populations, M1 was significantly greater in even years when juvenile pink salmon ( Oncorhynchus gorbuscha ) are abundant in the Strait of Georgia, suggesting that interspecific competition there has little effect on M1. All correlations of M1 with regional pink salmon or sockeye salmon abundances, lagged to align ocean entry years, were negative, but few (pink) or none (sockeye) were statistically significant. The negative correlations were due to the long-term changes (pink salmon abundance increasing, sockeye M1 smaller). Odd year dominance of juvenile pink salmon in northern British Columbia, Canada, is persistent and corresponds with the biennial pattern of M1 variation in Fraser River sockeye salmon and may be the source of the significant odd–even year line effect on M1.

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