A Note on Variability of Marine Survival of Sockeye Salmon (Oncorhynchus nerka) and Effects of Flooding on Spawning Success

1987 ◽  
Vol 44 (10) ◽  
pp. 1791-1795 ◽  
Author(s):  
Richard E. Thorne ◽  
James J. Ames
Keyword(s):  
Sockeye Salmon ◽  
River Flow ◽  
Oncorhynchus Nerka ◽  
Major Effect ◽  
Flow Conditions ◽  
Annual Variability ◽  
Lake Washington ◽  
Salmon Stock ◽  
Marine Survival ◽  
Spawning Success

Most of the annual variability in sockeye salmon (Oncorhynchus nerka) survival has been assumed to be associated with freshwater stages, while marine survival has been assumed to be very consistent from year to year. Data from Lake Washington sockeye salmon stock, including hydroacoustic surveys of presmolt populations, indicate that marine survival may vary on the order of 4–20%. However, the data also show that river flow conditions during spawning and gravel incubation have a major effect on production for this stock.

Model of Salmon Age Structure and Its Use in Preseason Forecasting and Studies of Marine Survival

1982 ◽  
Vol 39 (11) ◽  
pp. 1444-1452 ◽  
Author(s):  
Randall M. Peterman
Keyword(s):  
Survival Rate ◽  
Density Dependence ◽  
Age Structure ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Spawning Areas ◽  
Forecasting Method ◽  
Salmon Stock ◽  
Marine Survival ◽  
Stock Abundance

A method is derived to determine whether ocean abundance of a salmon stock affects either the survival rate between particular ages or the proportion of the ocean population which migrates back to freshwater spawning areas. The approach, similar to Fredin's smolt indices method, uses data on brood-year contributions to adult returns in successive years. Survival rate and proportion maturing are found to be independent of stock abundance after age 3, except in Naknek River sockeye (Oncorhynchus nerka) data. In cases such as Babine Lake sockeye salmon, where nonlinearity has been identified previously in the relation between smolt abundance and total adult returns, this lack of density dependence in the older ages means that the mortality processes which cause that nonlinearity act early in smolt life. The relations between abundance of adult returns of age n in year t and returns of age n + 1 from the same brood class in year t + 1 are useful as preseason forecasting techniques. The method derived here, which uses logarithms of abundances, improves upon the existing forecasting method. Deviations from the relation between abundances of brood-year returns can in some cases be explained by smolt weight, which is shown to affect mean age at return.Key words: salmon age structure, marine survival, age-at-return, smolt weight, preseason forecasting

An Acoustic Estimate of the Escapement of Sockeye Salmon (Oncorhynchus nerka) into Lake Washington in 1971

1974 ◽  
Vol 31 (2) ◽  
pp. 222-225 ◽  
Author(s):  
Richard E. Thorne ◽  
James J. Dawson
Keyword(s):  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Spawning Migration ◽  
Spawning Ground ◽  
Large Fish ◽  
Before And After ◽  
Lake Washington

The feasibility of estimating the escapement of sockeye salmon (Oncorhynchus nerka) into Lake Washington by hydroacoustics was explored during 1971. Surveys were made of large fish targets within the lake just before and after the spawning migration of sockeye salmon up the Cedar River. A decrease was observed after the spawning migration comparable to the estimated escapement as determined by weir counts and spawning ground surveys.

Nonlinear Relation Between Smolts and Adults in Babine Lake Sockeye Salmon (Oncorhynchus nerka) and Implications for Other Salmon Populations

1982 ◽  
Vol 39 (6) ◽  
pp. 904-913 ◽  
Author(s):  
Randall M. Peterman
Keyword(s):  
Measurement Error ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Life Stage ◽  
Pink Salmon ◽  
Accurate Estimate ◽  
Large Variability ◽  
Marine Life ◽  
Mortality Effect ◽  
Marine Survival

Data on sampling variability in smolt abundance for Babine Lake sockeye salmon (Oncorhynchus nerka) are combined with a previous analysis to calculate a more accurate estimate of the degree of nonlinearity in the relation between smolts and adults. Results indicate significant within-stock nonlinear mortality, large variability in mortality which tends to obscure any smolt-to-adult relation, or both. Analysis of age structure data identifies the first 15 mo of marine life as the period when most of this nonlinear or relation-masking mortality occurs. I also calculate the amount of smolt measurement error below which other salmon stocks are classed as having nonlinear marine survival. A distinct separation between even and odd brood year marine survival of Babine Lake sockeye suggests interactions with pink salmon. Juvenile pink salmon (O. gorbuscha) abundances correlate positively with residuals in Babine Lake sockeye survival for the same seaward migration year. This suggests a depensatory mortality effect which occurs later in the marine life stage than the possible within-population compensatory effect. Depensation is plausible because the size of pink fry equals that of sockeye smolts by August in coastal waters, permitting mutual swamping of predators. The paper concludes with implications for further enhancement.Key words: density dependence, marine survival, measurement error, enhancement, depensation, nonlinear, variability

Application of Bayesian decision analysis to management of a sockeye salmon (Oncorhynchus nerka) fishery

1998 ◽  
Vol 55 (1) ◽  
pp. 86-98 ◽  
Author(s):  
Christina A Robb ◽  
Randall M Peterman
Keyword(s):  
Decision Analysis ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Data Uncertainty ◽  
Optimal Decision ◽  
Management Decision ◽  
Bayesian Decision ◽  
Stock Recruitment ◽  
Salmon Stock ◽  
Parameter Values

We developed a decision-making framework for management of a sockeye salmon (Oncorhynchus nerka) fishery on the Nass River, British Columbia, that explicitly accounts for uncertainties in (i) the stock-recruitment relationship, (ii) annual recruitment, (iii) run timing, and (iv) catchability. The method used Monte Carlo simulation within a decision analysis framework and used Bayesian statistics to calculate probabilities for parameter values in the Shepherd stock-recruitment model. The decision dealt with when to open a fishery, upstream of all normal fishing areas, that is intended to harvest fish that are considered surplus to spawning requirements. The optimal decision rule for opening this fishery depended on (i) the relative importance of different management objectives and (ii) the range of shapes of the stock-recruitment relationship that were admitted as possible within the decision analysis. The management decision that was optimal if we assumed a dome-shaped stock-recruitment relationship was not optimal when we admitted the possibility of other shapes of the relationship. Therefore, given the variability in salmon stock-recruitment data, uncertainty in the shape of the stock-recruitment relationship should be routinely considered in analyses of management decisions.

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

1988 ◽  
Vol 45 (4) ◽  
pp. 586-591 ◽  
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.

Spawning success of males using alternative mating tactics in sockeye salmon, Oncorhynchus nerka

1997 ◽  
Vol 54 (8) ◽  
pp. 1785-1795 ◽  
Author(s):  
C J Foote ◽  
G S Brown ◽  
C C Wood
Keyword(s):  
Sockeye Salmon ◽  
Pacific Salmon ◽  
Oncorhynchus Nerka ◽  
Relative Size ◽  
Mating Strategies ◽  
Older Individuals ◽  
Alpha Male ◽  
Gonad Size ◽  
Sperm Volume ◽  
Spawning Success

Protein electrophoresis was used to determine the relative spawning success of jack sockeye salmon, Oncorhynchus nerka, males when they joined spawnings of larger, older individuals in experimental enclosures in the natal stream, Pierre Creek, Babine Lake, British Columbia. We attempted to relate the results to distance of the jack from female before spawning and relative size of the jack to the alpha male. Further, we measured the relationships between relative gonad size and available sperm volume to body size to determine if sperm competition could also play a role in determining the relative spawning success of males. Jack spawning success was variable (3-93%) and not significantly different from that of large males, even though they were further from the female before spawning, had smaller gonads, and had less available sperm. Jack males were adept at sneaking, usually commencing spawning within a split second of the alpha male and always on the opposite, free, side of the spawning female. The results are related to various theories on the evolution of alternative mating strategies and tactics in Pacific salmon.

Sockeye salmon (Oncorhynchus nerka) nursery lake fertilization: Review and summary of results

2004 ◽  
Vol 12 (3) ◽  
pp. 133-162 ◽  
Author(s):  
K D Hyatt ◽  
D J McQueen ◽  
K S Shortreed ◽  
D P Rankin
Keyword(s):  
Food Web ◽  
Green Algae ◽  
Sockeye Salmon ◽  
Inorganic Nitrogen ◽  
Oncorhynchus Nerka ◽  
Adult Survival ◽  
Bottom Up ◽  
Blue Green Algae ◽  
Marine Survival ◽  
Lake Fertilization

We reviewed 24 sockeye salmon (Oncorhynchus nerka) nursery lake experiments that involved whole-lake fertilization with appropriate treatment and control years. We found that: 21 of 21 studies showed that fertilization was associated with increased chlorophyll a concentrations, 16 of 16 showed increased zooplankton biomasses, 16 of 16 demonstrated increased average smolt weights, and 11 of 13 showed increased smolt biomasses. Studies involving assessments of egg-to-smolt survival were rare, but all (4 of 4) showed increased survival rates. Studies involving increased smolt-to-adult survival (i.e., marine survival) were even rarer, but all (3 of 3) showed that lake fertilization and increased smolt size were associated with increased marine survival. Several fertilization studies reported problems, and some offered solutions. For instance, when whole-lake fertilization stimulated the growth of blue-green algae, fertilizer with higher nitrogen to phosphorus ratios was used to control the problem. Conversely, when high nitrogen to phosphorus ratios were associated with blooms of ungrazable diatoms, notably Rhizosolenia eriensis, reduced nitrate concentrations were recommended. To date, solutions designed to constrain the growth of both blue-green algae and Rhizosolenia blooms remain elusive. Some studies showed that when both mysids (large invertebrate planktivores) and juvenile sockeye inhabit the same lake, sockeye suffer from a competitive disadvantage and mysids consume 80–90% of the available zooplanktonic food production. Similarly, a small number of studies demonstrated that competition from sticklebacks (Gasterosteus aculeatus) adversely affected sockeye growth rates, and although the problem remains unresolved, ongoing work in lakes containing kokanee (O. nerka), suggests that stocked cutthroat trout (Salmo clarki) may be capable of controlling stickleback densities through predation. Despite all of these difficulties, in almost all cases, when lakes were fertilized with various mixtures of inorganic nitrogen and phosphorus, pelagic food web bottom-up control was strong enough and predictable enough to ensure that sockeye smolt biomass increased. We conclude that sockeye nursery lake fertilization is a technique that can contribute usefully to both the enhancement and conservation of sockeye salmon populations. Key words: sockeye salmon, lake fertilization, bottom-up, aquatic food web.

Evidence for the existence of a native population of sockeye salmon (Oncorhynchus nerka) and subsequent introgression with introduced populations in a Pacific Northwest watershed

2007 ◽  
Vol 64 (9) ◽  
pp. 1209-1221 ◽  
Author(s):  
Ingrid B Spies ◽  
Eric C Anderson ◽  
Kerry Naish ◽  
Paul Bentzen
Keyword(s):  
Pacific Northwest ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Past Century ◽  
The Past ◽  
Introduced Populations ◽  
Microsatellite Dna Markers ◽  
Lake Washington ◽  
Baker Lake ◽  
Bear Creek

The Lake Washington watershed (Washington, USA) has been the recipient of numerous transplantations of nonnative Oncorhynchus nerka (both sockeye salmon and their landlocked form, kokanee) over the past century and currently contains self-sustaining populations of both ecotypes. Microsatellite DNA markers were used to identify native and introduced groups while characterizing population structure. This study confirmed that Baker Lake sockeye transplantations during the 20th century contributed to three current sockeye populations: Cedar River, Issaquah Creek, and Pleasure Point Beach in the Lake Washington watershed. Distinctive allele distributions at two loci, One101 and One114, provide evidence that a fourth Lake Washington sockeye population, Bear Creek, is divergent from other Lake Washington sockeye and may be of substantially native origin despite heavy stocking activity in the watershed over the past century. Data from these loci also suggest the presence of native genes in populations that had been regarded as entirely of introduced origin.

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