Survival of Puget Sound chinook salmon (Oncorhynchus tshawytscha) in response to climate-induced competition with pink salmon (Oncorhynchus gorbuscha)

2004 ◽  
Vol 61 (9) ◽  
pp. 1756-1770 ◽  
Author(s):  
Gregory T Ruggerone ◽  
Frederick A Goetz
Keyword(s):  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Pink Salmon ◽  
Puget Sound ◽  
Oncorhynchus Gorbuscha ◽  
First Year ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Growth And Survival ◽  
Coastal Streams ◽  
Delayed Maturation

We tested for competition between pink salmon (Oncorhynchus gorbuscha) and chinook salmon (Oncorhynchus tshawytscha) originating from rivers in the Puget Sound area using coded-wire-tagged subyearling hatchery chinook salmon. Following a 2-year life cycle, many juvenile pink salmon enter Puget Sound in even-numbered years, whereas few migrate during odd-numbered years. During 1984–1997, juvenile chinook salmon released during even-numbered years experienced 59% lower survival than those released during odd-numbered years, a trend consistent among 13 chinook salmon stocks. Lower even-numbered-year survival of chinook salmon was associated with reduced first-year growth and survival and delayed maturation. In contrast, chinook salmon released into coastal streams, where few pink salmon occur, did not exhibit an alternating-year pattern of survival, suggesting that the interaction occurred within Puget Sound and the lower Strait of Georgia. Unexpectedly, the survival pattern of Puget Sound chinook salmon was reversed prior to the 1982–1983 El Niño: chinook salmon survival was higher when they migrated with juvenile pink salmon during 1972–1983. We hypothesize that chinook salmon survival changed as a result of a shift from predation- to competition-based mortality in response to recent declines in predator and prey abundances and increases in pink salmon abundance. Alternating-year mortality accounted for most of the 50% decline in marine survival of chinook salmon between 1972–1983 and 1984–1997.

Comparison of the effect of salmon gonadotropin administered by pellet implantation or injection on sexual development of juvenile male pink salmon (Oncorhynchus gorbuscha)

1978 ◽  
Vol 56 (1) ◽  
pp. 86-89 ◽  
Author(s):  
Colin N. MacKinnon ◽  
Edward M. Donaldson
Keyword(s):  
Body Weight ◽  
Chinook Salmon ◽  
Sexual Development ◽  
Oncorhynchus Tshawytscha ◽  
Pink Salmon ◽  
Mitotic Division ◽  
Oncorhynchus Gorbuscha ◽  
Juvenile Male ◽  
Time Intervals ◽  
Pink Salmon Oncorhynchus Gorbuscha

In juvenile male pink salmon complete maturity was induced by September in the year of hatching by both pellet implantation (once per 3 weeks) and injection (thrice weekly) of 1.0μg of chinook salmon (Oncorhynchus tshawytscha) gonadotropin per gram body weight. Time of onset of mitotic division of spermatogonia and rate of spermatogenesis were accelerated in the precociously mature testes. Similar doses of salmon gonadotropin injected at longer time intervals (once per week and once per 2 weeks) resulted in slower maturation.

Induction of precocious sexual development in female pink salmon (Oncorhynchus gorbuscha)

1973 ◽  
Vol 51 (5) ◽  
pp. 493-500 ◽  
Author(s):  
James D. Funk ◽  
Edward M. Donaldson ◽  
Helen M. Dye
Keyword(s):  
Body Weight ◽  
Chinook Salmon ◽  
Sexual Development ◽  
Oncorhynchus Tshawytscha ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Ovarian Maturation ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Large Numbers ◽  
Estradiol 17Β

Acceleration of ovarian maturation was achieved in immature pink salmon (Oncorhynchus gorbuscha) with injections of chinook (spring) salmon (Oncorhynchus tshawytscha) gonadotropin alone, and in combination with estradiol 17β. Oocytes containing yolk globules were evident in fish treated three times per week with 1.0 μg/g body weight salmon gonadotropin in combination with 1.5 μg/g body weight estradiol 17β for 126 days. After 168 days they were also seen in salmon treated with the same dosage of salmon gonadotropin alone. Estradiol 17β alone, at a dosage of 15 μg/g body weight, or in combination with salmon gonadotropin, inhibited vitellogenesis. Formation of oocytes 2 mm in diameter required [Formula: see text] months of treatment with 1.0 μg/g body weight salmon gonadotropin in combination with 1.5 μg/g body weight estradiol 17β, and 9 months of injections with 1.0 μg/g body weight gonadotropin alone. Few large yolky oocytes were developed by any of the treatments. Large numbers of preovulatory corpora atretica were observed in all treated fish.Only a small amount of histochemically demonstrable Δ5-3β hydroxysteroid dehydrogenase activity was present in ovaries from pink or chinook salmon juveniles treated for 3 months with various dosages of salmon gonadotropin.

Differences in breeding Lake Superior pink salmon (Oncorhynchus gorbuscha (Walbaum)) associated with variation in thyroid hyperplasia

1988 ◽  
Vol 66 (12) ◽  
pp. 2688-2694 ◽  
Author(s):  
Douglas B. Noltie
Keyword(s):  
Lake Superior ◽  
Pink Salmon ◽  
Lesion Size ◽  
Oncorhynchus Gorbuscha ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Wide Range ◽  
Post Spawning ◽  
Delayed Maturation ◽  
Thyroid Hyperplasia ◽  
Lesion Severity

Pink salmon (Oncorhynchus gorbuscha (Walbaum)) from eastern Lake Superior exhibit various degrees of thyroid hyperplasia. A link between goitrogenesis and growth is suggested by the increased prevalence of large lesions among large fish of both sexes. Despite males being larger than females, however, lesion prevalence did not differ between the sexes. More large lesions occurred among late migrants, especially males, indicating a seasonal increase in hyperplasticity. Delayed stream entry occurred in overtly lesioned fish of both sexes, evidence of a possible inhibition of maturation. Males and females differed in condition (weight-at-length) with lesion severity. Females with overt lesions showed reduced secondary sexual character development, more so than males. The pre- and post-spawning testis characteristics of males generally did not differ with lesion size, although the testes of spawned-out males with large lesions did have higher water contents. In females, the reduced water content of eggs in severely lesioned individuals was evidence of delayed maturation. Enlarged livers occurred in badly lesioned females, but not in males. In neither sex did severely lesioned fish exhibit shorter breeding life-spans. In overview, this study demonstrates that a wide range of effects is associated with differences in the severity of thyroid hyperplasia exhibited by Lake Superior pink salmon, these also being mediated by apparent differences in physiology between the sexes.

Meristic and morphometric variation in pink salmon (Oncorhynchus gorbuscha) in southern British Columbia and Puget Sound

1985 ◽  
Vol 63 (2) ◽  
pp. 366-372 ◽  
Author(s):  
Terry D. Beacham
Keyword(s):  
British Columbia ◽  
Pink Salmon ◽  
Puget Sound ◽  
Genetic Differences ◽  
Oncorhynchus Gorbuscha ◽  
Morphometric Variation ◽  
Morphometric Characters ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Local Water ◽  
Gill Raker

Variation in the number of gill rakers and four morphometric characters was examined for 4 stocks from the even-year brood line and 20 stocks from the odd-year brood line of pink salmon (Oncorhynchus gorbuscha) in southern British Columbia and Puget Sound. Significant differences in gill-raker frequencies were observed among stocks within each brood line, but differences were greater between the brood lines than within each brood line. Sizes of the morphometric characters standardized to a body length of 419 mm were also variable among stocks within a brood line, but stocks spawning in rivers in the same region in alternate years were more similar morphometrically than to those spawning in different regions. It is suggested that patterns of meristic and morphometric variability are reflective of genetic differences, with meristic variability illustrating the genetic differences between the brood lines, and morphometric variability reflecting adaptation to local water velocity conditions in the streams the stocks return to during spawning.

Heterozygosity and morphological variability of pink salmon (Oncorhynchus gorbuscha) from southern British Columbia and Puget Sound

1985 ◽  
Vol 27 (5) ◽  
pp. 571-579 ◽  
Author(s):  
Terry D. Beacham ◽  
Ruth E. Withler
Keyword(s):  
British Columbia ◽  
Pink Salmon ◽  
Puget Sound ◽  
Oncorhynchus Gorbuscha ◽  
Phenotypic Variance ◽  
Meristic Characters ◽  
Morphometric Variation ◽  
Morphometric Characters ◽  
Mahalanobis Distances ◽  
Pink Salmon Oncorhynchus Gorbuscha

We compared variability in gill raker number and four morphometric characters with heterozygosity at enzymatic loci within and among populations of pink salmon (Oncorhynchus gorbuscha) in southern British Columbia and Puget Sound. Among individuals, there was no relationship between levels of heterozygosity at eight electrophoretic loci and degree of meristic or morphometric variation. Decreased phenotypic variance was not associated with increased heterozygosity. Among populations of pink salmon, increased levels of average heterozygosity were not associated with decreased phenotypic variation. Our results do not support the hypothesis that more heterozygous individuals are less phenotypically variable than more homozygous ones as a result of genetic homeostasis and a canalisation of morphology during development. Genetic distances between pairs of pink populations were significantly correlated with pairwise Mahalanobis distances derived from meristic characters (gill rakers) and less strongly correlated with distances derived from morphometric characters. Pink salmon are morphometrically adapted to the natal stream environment, whereas biochemical and meristic characters in these populations may be less affected differentially by local selective forces.Key words: salmon, electromorphs, homeostasis, genetic variability, heterozygosity.

Fertilization of Pink Salmon (Oncorhynchus gorbuscha) Ova by Spermatozoa from Gonadotropin-Injected Juveniles

1972 ◽  
Vol 29 (1) ◽  
pp. 13-18 ◽  
Author(s):  
Edward M. Donaldson ◽  
James D. Funk ◽  
F. C. Withler ◽  
R. B. Morley
Keyword(s):  
British Columbia ◽  
Sexual Maturation ◽  
Chinook Salmon ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Testicular Development ◽  
Fraser River ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Early Maturation ◽  
Two Stages

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.

Development of nutritional and environmental strategies for maximizing the growth and survival of juvenile pink salmon (Oncorhynchus gorbuscha)

Aquaculture ◽  
1985 ◽  
Vol 47 (2-3) ◽  
pp. 113-130 ◽  
Author(s):  
David A. Higgs ◽  
Jack R. Markert ◽  
M.Dianne Plotnikoff ◽  
Jack R. McBride ◽  
Bakhshish S. Dosanjh
Keyword(s):  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Growth And Survival ◽  
Environmental Strategies

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

2012 ◽  
Vol 69 (9) ◽  
pp. 1499-1512 ◽  
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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