Coastal Movements of Mature Fraser River Pink Salmon (Oncorhynchus gorbuscha) as Revealed by Ultrasonic Tracking

1973 ◽  
Vol 30 (9) ◽  
pp. 1309-1316 ◽  
Author(s):  
A. B. Stasko ◽  
R. M. Horrall ◽  
A. D. Hasler ◽  
D. Stasko

Eleven mature pink salmon (Oncorhynchus gorbuscha) were tracked in September 1967 for periods of 3–50 hr over distances from 2 to 127 km to determine migration patterns.The fish were classified as "active" or "passive." Active fish moved faster and their paths were straighter. Active tracks ended distant from and to the north (toward the Fraser River) of the release point; passive tracks ended near or south of the release point. Active fish did not follow shorelines, but travelled primarily along the axes of tidal currents. They moved both with the northward flood and against the southward ebb currents, during day and at night. Average ground speed of active fish was 62 cm/sec (2.2 km/hr).

1998 ◽  
Vol 55 (2) ◽  
pp. 281-296 ◽  
Author(s):  
Carl James Schwarz ◽  
Carolyn Gail Taylor

The simple-Petersen estimator is a well-known mark-recapture method to estimate animal abundance. Two key assumptions are equal catchability in both samples and complete mixing of tagged and untagged animals. If these are violated, severe bias can occur. The stratified-Petersen estimator can be used to account for some of the heterogeneity in catchability or mixing. In this paper, we first review recent developments in the stratified-Petersen experiment for fisheries audiences and demonstrate some of the practical problems that can occur that have not been discussed in the theoretical literature. Second, we present a case study to estimate the gross escapement of Fraser River pink salmon (Oncorhynchus gorbuscha) in 1991. The motivation for this study is a discrepancy of over 5 million fish between the estimates as derived by the Pacific Salmon Commission (PSC) (7.5 million fish based on a hydroacoustic method) and the Department of Fisheries and Oceans (DFO), Canada (13.0 million fish based on a mark-recapture method). One hypothesis put forward was that the discrepancy may be due to the use of a pooled-Petersen estimator when there is differential migration over time. The stratified-Petersen model suggests that little of this discrepancy can be explained by differential migration.


1938 ◽  
Vol 4a (2) ◽  
pp. 141-150 ◽  
Author(s):  
A. L. Pritchard

In 1931, 1933, 1935, odd-numbered years, when no natural runs of pink salmon (Oncorhynchus gorbuscha) occur in the Masset area, British Columbia, transfers of eggs were made from the Tlell river on the east coast of Graham island to McClinton creek, a tributary of Masset inlet. The following free-swimming fry were released: from the 1931 experiment—753,646 normal and 124,002 "marked" by the removal of the adipose and left ventral fins, and from that of 1935—397,657 normal and 108,200 "marked" by the removal of the adipose and right ventral fins. From the former, 40 "marked" adults were recovered in the Fraser river fishery in 1933, and from the latter four "marked" adults at McClinton creek in 1937. In the 1933 experiment 540,294 eyed eggs were planted but these were destroyed by freshets the following winter. Possible reasons for the failure of these experiments and the absolute blank in the "off" years are suggested.


1987 ◽  
Vol 44 (2) ◽  
pp. 348-356 ◽  
Author(s):  
I. V. Williams ◽  
J. R. Brett

Critical swimming speeds were determined for male and female pink salmon (Oncorhynchus gorbuscha) captured from the Fraser and Thompson rivers and Seton Creek, British Columbia. The fish were categorized into two basic groups. Lower river fish were captured from the Fraser River at Fort Langley and Yale, and up-river fish were captured from the Thompson River at the Canyon and at Ashcroft and from Seton Creek near Lillooet, British Columbia. The critical swimming speeds of males and females in various stages of maturation were compared. In general, the up-river fish were stronger swimmers than the lower river fish. Gravid fish were stronger swimmers than spawning fish, which in turn were stronger swimmers than fish which were spawned out. Standardized critical swimming speeds ranged from a mean of 1.73 ± 0.35 (SE) body lengths/s for spawned females up to 3.39 ± 0.48 lengths/s for up-river gravid males.


1972 ◽  
Vol 29 (1) ◽  
pp. 13-18 ◽  
Author(s):  
Edward M. Donaldson ◽  
James D. Funk ◽  
F. C. Withler ◽  
R. B. Morley

Sexual maturation in male pink salmon (Oncorhynchus gorbuscha) from Jones Creek, a tributary of the Fraser River, British Columbia, was accelerated by intraperitoneal injections of partially purified chinook salmon (O. tshawytscha) gonadotropin. The treated pinks produced milt 1 year earlier than normal. Milt from these fish was compared with milt from wild Lower Babine River pinks with respect to its ability to fertilize the ova of Lower Babine River females. There were no marked differences in proportions of ova fertilized, in survival to hatching, or in numbers of deformed larvae. Densities of sperm in the milt from treated males ranged from 0.15 × 109 to 7.35 × 109 per ml; sperm densities in the milt from wild males ranged from 19.3 × 109 to 38.6 × 109 per ml. Two stages in testicular development were identified among the treated males and found to be directly related to the success of fertilization. The significance of induced early maturation in attempts to establish pink runs in the "off" year rivers is discussed.


2017 ◽  
Vol 74 (8) ◽  
pp. 1233-1242 ◽  
Author(s):  
Ricardo O. Amoroso ◽  
Michael D. Tillotson ◽  
Ray Hilborn

Hatchery production of juvenile fish for release into the wild has been practiced for well over a century in an effort to increase the number of salmon available to harvest. In this study, we evaluate the net impact of the largest such program in North America, the hatchery program for pink salmon (Oncorhynchus gorbuscha) in Prince William Sound (PWS), Alaska. At the same time the hatchery program was increasing in output, there was a major change in productivity in the North Pacific so that throughout Alaska pink salmon increased dramatically in abundance between the 1970s and the 2000s. Using other regions of Alaska as reference sites, we estimate that the PWS hatchery program has increased the total catch by an average of 17 million fish, of which 8 million have been allocated to pay hatchery operating expenses. We estimate that the maximum sustainable yield (MSY) of wild spawning fish in PWS has increased slightly (28%), while in regions of Alaska without pink salmon hatchery programs the MSY has tripled. Our results support the use of a precautionary approach to future large-scale stock enhancement efforts.


2008 ◽  
Vol 65 (10) ◽  
pp. 2178-2190 ◽  
Author(s):  
Yunbo Xie ◽  
Catherine G.J. Michielsens ◽  
Andrew P. Gray ◽  
Fiona J. Martens ◽  
Jacqueline L. Boffey

Detailed avoidance reactions of adult migrating salmon to a mobile survey vessel were successfully observed with side-looking dual-frequency identification sonar (DIDSON) in the lower Fraser River (British Columbia, Canada). Both adult sockeye ( Oncorhynchus nerka ) and pink salmon ( Oncorhynchus gorbuscha ) returning to the river were found to avoid the approaching vessel by initiating lateral movements away from the vessel, making the fish unlikely to be insonified by the downward-looking transducers towed by the vessel. The vessel was found to have an estimated mean interference range of 4 m from its propeller. Analyses of the data concluded that once the vessel and fish were separated by more than 7 m, the vessel no longer affected the normal migration behaviour of the fish.


2015 ◽  
Vol 72 (6) ◽  
pp. 818-833 ◽  
Author(s):  
Gregory T. Ruggerone ◽  
Brendan M. Connors

Sockeye salmon (Oncorhynchus nerka) populations from Southeast Alaska through British Columbia to Washington State have experienced similar declines in productivity over the past two decades, leading to economic and ecosystem concerns. Because the declines have spanned a wide geographic area, the primary mechanisms driving them likely operate at a large, multiregional scale at sea. However, identification of such mechanisms has remained elusive. Using hierarchical models of stock–recruitment dynamics, we tested the hypothesis that competition between pink (Oncorhynchus gorbuscha) and sockeye salmon for prey has led to reduced growth and productivity and delayed maturation of up to 36 sockeye populations spanning the region during the past 55 years. Our findings indicate the abundance of North Pacific pink salmon in the second year of sockeye life at sea is a key factor contributing to the decline of sockeye salmon productivity, including sockeye in the Fraser River where an increase from 200 to 400 million pink salmon is predicted to reduce sockeye recruitment by 39%. Additionally, length-at-age of Fraser River sockeye salmon declined with greater sockeye and pink salmon abundance, and age at maturity increased with greater pink salmon abundance. Our analyses provide evidence that interspecific competition for prey can affect growth, age, and survival of sockeye salmon at sea.


2012 ◽  
Vol 69 (9) ◽  
pp. 1499-1512 ◽  
Author(s):  
Skip McKinnell ◽  
Maxine Reichardt

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.


1985 ◽  
Vol 42 (9) ◽  
pp. 1474-1483 ◽  
Author(s):  
Terry D. Beacham ◽  
Ruth E. Withler ◽  
Allan P. Gould

We used electrophoresis to examine genetic variability at 12 loci for 4 even-year broodline stocks and at 14 loci for 21 odd-year broodline stocks of pink salmon (Oncorhynchus gorbuscha) in southern British Columbia and Puget Sound. Allelic frequencies were most heterogeneous between the two pink salmon broodlines, but within the odd-year broodline, Fraser River, Canadian non-Fraser, and Puget Sound pink salmon had significantly different allelic frequencies at some loci. Canadian non-Fraser River stocks had the greatest heterogeneity of allelic frequencies within a region, whereas the Fraser River stocks had the least amount of heterogeneity. There was no significant two-locus linkage disequilibrium for the pink salmon stocks surveyed. Cluster analyses by allelic frequencies indicated that Fraser River, Canadian non-Fraser, and Puget Sound stocks were reasonably distinctive. We used differences in genotypic frequencies at 11 loci (3 were duplicated loci) to estimate stock composition of these three groups of pink salmon in mixtures in which the true compositions were known, and we were able to compare the accuracy and precision of our estimates with respect to mixture size and stock composition. We estimated that 100% of pink salmon sampled in a test fishery in Thompson Sound were of Canadian non-Fraser origin.


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