Estimation of eggs lost from superimposed pink salmon (Oncorhynchus gorbuscha) redds

1998 ◽  
Vol 55 (3) ◽  
pp. 618-625 ◽  
Author(s):  
M Fukushima ◽  
T J Quinn ◽  
W W Smoker
Keyword(s):  
Maximum Likelihood ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Male And Female ◽  
Stream Discharge ◽  
Density Dependent Mortality ◽  
Repeated Use ◽  
Redd Superimposition ◽  
Dependent Mortality

This study investigated whether repeated use of limited spawning grounds (i.e., redd superimposition) by pink salmon (Oncorhynchus gorbuscha) can cause density-dependent mortality. Loss of eggs from part of Auke Creek, Alaska, was estimated from a series of mark-recapture experiments and maximum likelihood models. The number of eggs lost per day during the 5-week spawning season and for 2 weeks afterward was roughly proportional to spawner abundance and weakly related to stream discharge. Freshets after cessation of spawning induced negligible egg loss. The maximum daily egg loss estimated by one model was 398 000 eggs (80% CI = 267 000 - 1 581 000) or equivalently a loss of about 300 female spawners when the daily spawner abundance (both male and female) in the study area was at most 1000.

scholarly journals Cycles, stochasticity and density dependence in pink salmon population dynamics

2010 ◽  
Vol 278 (1714) ◽  
pp. 2060-2068 ◽  
Author(s):  
Martin Krkošek ◽  
Ray Hilborn ◽  
Randall M. Peterman ◽  
Thomas P. Quinn
Keyword(s):  
Density Dependence ◽  
Disease Transmission ◽  
Pink Salmon ◽  
The Other ◽  
Oncorhynchus Gorbuscha ◽  
Stochastic Perturbations ◽  
Density Dependent ◽  
Density Dependent Mortality ◽  
Animal Populations ◽  
Dependent Mortality

Complex dynamics of animal populations often involve deterministic and stochastic components. A fascinating example is the variation in magnitude of 2-year cycles in abundances of pink salmon ( Oncorhynchus gorbuscha ) stocks along the North Pacific rim. Pink salmon have a 2-year anadromous and semelparous life cycle, resulting in odd- and even-year lineages that occupy the same habitats but are reproductively isolated in time. One lineage is often much more abundant than the other in a given river, and there are phase switches in dominance between odd- and even-year lines. In some regions, the weak line is absent and in others both lines are abundant. Our analysis of 33 stocks indicates that these patterns probably result from stochastic perturbations of damped oscillations owing to density-dependent mortality caused by interactions between lineages. Possible mechanisms are cannibalism, disease transmission, food depletion and habitat degradation by which one lineage affects the other, although no mechanism has been well-studied. Our results provide comprehensive empirical estimates of lagged density-dependent mortality in salmon populations and suggest that a combination of stochasticity and density dependence drives cyclical dynamics of pink salmon stocks.

Critical Swimming Speed of Fraser and Thompson River Pink Salmon (Oncorhynchus gorbuscha)

1987 ◽  
Vol 44 (2) ◽  
pp. 348-356 ◽  
Author(s):  
I. V. Williams ◽  
J. R. Brett
Keyword(s):  
British Columbia ◽  
Swimming Speed ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Fraser River ◽  
Critical Swimming Speed ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Male And Female ◽  
Males And Females ◽  
River Fish

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.

Supplementary Checks on the Scales of Pink Salmon (Oncorhynchus gorbuscha) and Chum Salmon (O. keta)

1965 ◽  
Vol 22 (6) ◽  
pp. 1477-1489 ◽  
Author(s):  
H. T. Bilton ◽  
W. E. Ricker
Keyword(s):  
British Columbia ◽  
Chum Salmon ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Commercial Fisheries ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Clear Cut ◽  
Second Year Of Life ◽  
Second Year ◽  
Similar Incidence

Among 159 central British Columbia pink salmon that had been marked by removal of two fins as fry and had been recovered in commercial fisheries after one winter in the sea, the scales of about one-third showed a supplementary or "false" check near the centre of the scale, in addition to the single clear-cut annulus. This evidence from fish of known age confirms the prevailing opinion that such extra checks do not represent annuli, hence that the fish bearing them are in their second year of life rather than their third. Unmarked pink salmon from the same area, and some from southern British Columbia, had a generally similar incidence of supplementary checks. In both marked and unmarked fish the supplementary checks varied in distinctness from faint to quite clear. In a sample of scales of 14 double-fin marked chum salmon which were known to be in their 4th year, all fish had the expected 3 annuli, and 12 fish had a supplementary check inside the first annulus.

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