A hierarchical model for salmon run reconstruction and application to the Bristol Bay sockeye salmon (Oncorhynchus nerka) fishery

2006 ◽  
Vol 63 (7) ◽  
pp. 1564-1577 ◽  
Author(s):  
Lucy Flynn ◽  
André E Punt ◽  
Ray Hilborn
Keyword(s):  
Hierarchical Structure ◽  
Sockeye Salmon ◽  
Pacific Salmon ◽  
Oncorhynchus Nerka ◽  
Model Development ◽  
Bristol Bay ◽  
Process Error ◽  
The Hierarchical Structure ◽  
River Test ◽  
Run Timing

The goal of spreading the annual catch of a Pacific salmon (Oncorhynchus spp.) run proportionally across all segments of the migration is rendered difficult or impossible because of the interannual variability in both run size and run timing. This problem is particularly acute in the case of the fishery for sockeye salmon (Oncorhynchus nerka) in Bristol Bay, Alaska, for which traditional run reconstruction models are not applicable because of the extreme temporal compression of the run. We develop a run reconstruction model appropriate for sockeye salmon in Bristol Bay by accounting for the hierarchical structure of the problem and by including process error. Our results indicate that the hierarchical structure is, in fact, not necessary, whereas the process error parameters are needed to fit the data. We suggest further model development without the hierarchical structure, including incorporating in-river test fishing data. The results of our method can be used to address questions regarding environmental or intrinsic drivers of run timing and the possibility of artificial selection on run timing.

The effects of salmon abundance and run timing on the performance of management by emergency order

2015 ◽  
Vol 72 (10) ◽  
pp. 1518-1526 ◽  
Author(s):  
Milo D. Adkison ◽  
Curry J. Cunningham
Keyword(s):  
Genetic Diversity ◽  
Management Strategy ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Bristol Bay ◽  
Detailed Model ◽  
Management Strategy Evaluation ◽  
Strategy Evaluation ◽  
Historical Management ◽  
Run Timing

We examine the effect of uncertainty in salmon run abundance and run timing on the ability of managers to achieve escapement goals using in-season regulation of fishery openings using a detailed model of the arrival of salmon and operation of the fishery, the information available to managers, and managers’ behavior. We supplement this management strategy evaluation by examining historical management performance of sockeye salmon (Oncorhynchus nerka) fisheries from Bristol Bay, Alaska. We find that uncertainty about run timing exacerbates the effects of uncertainty about salmon abundance. Early-arriving small runs and late-arriving large runs are especially problematic, as they produce in-season data that mimic that of a typically sized run with average run timing. Managers faced with an early-arriving small run will tend to overharvest the fish, particularly the earliest-arriving component. Managers faced with a late-arriving large run will tend to underharvest the fish, and harvest the latest-arriving components at a higher rate. This differential harvest of early or late components of the run is important because it might reduce the genetic diversity of the stock, thus reducing its future productivity.

Nutrient export from freshwater ecosystems by anadromous sockeye salmon (Oncorhynchus nerka)

2004 ◽  
Vol 61 (9) ◽  
pp. 1582-1589 ◽  
Author(s):  
Jonathan W Moore ◽  
Daniel E Schindler
Keyword(s):  
Sockeye Salmon ◽  
Pacific Salmon ◽  
Oncorhynchus Nerka ◽  
Large Body ◽  
Freshwater Ecosystems ◽  
Nutrient Export ◽  
Nitrogen And Phosphorus ◽  
Bristol Bay ◽  
Fresh Waters

Anadromous and semelparous salmon transport nutrients from the ocean to fresh waters when they return to spawn and die, a process inspiring a large body of research on the role of salmon-derived nutrients in coastal ecosystems. However, salmon also transport nutrients out of fresh waters when they migrate to the ocean as smolts. Using a total of 76 years of age-specific smolt-migration and adult-escapement data, we calculated the amounts of nitrogen and phosphorus that sockeye salmon (Oncorhynchus nerka) imported and exported from four major systems in Bristol Bay, Alaska. Smolts removed an average of 16% of the phosphorus and 12% of the nitrogen that their parents transported into fresh waters. The percentage of parental nutrients that smolts exported varied through time and among sites, ranging from 1% to 65% of the phosphorus and from less than 1% to 47% of the nitrogen. In systems where smolts were larger, they exported a higher percentage of nutrients. Depending on the strength of density-dependence, smolts could theoretically export more nutrients than their parents import to freshwater ecosystems at low spawning densities. Ignoring nutrient export by outgoing smolts will consistently lead to overestimation of nutrient import by Pacific salmon to freshwater ecosystems.

Selective predation by brown bears (Ursus arctos) foraging on spawning sockeye salmon (Oncorhynchus nerka)

2000 ◽  
Vol 78 (6) ◽  
pp. 974-981 ◽  
Author(s):  
Gregory T Ruggerone ◽  
Renn Hanson ◽  
Donald E Rogers
Keyword(s):  
Sockeye Salmon ◽  
Ursus Arctos ◽  
Oncorhynchus Nerka ◽  
The Body ◽  
Upstream Migration ◽  
Selective Predation ◽  
Bristol Bay ◽  
Brown Bears ◽  
Risk Of Predation ◽  
Salmon Population

Selective predation by and predation rates of brown bears (Ursus arctos) foraging on spawning sockeye salmon (Oncorhynchus nerka) in a small shallow creek in the Wood River lake system near Bristol Bay, Alaska, were quantified during 1986 and 1990–1992. Bears killed a high proportion of spawning salmon when few salmon entered the creek (92% of 505 fish) and a much smaller proportion when the spawning population reached a historical high (16% of 15 631 fish). Selective predation on salmon that differed in length, sex, and spawning condition was measured by tagging salmon at the mouth of the creek immediately prior to upstream migration and then recovering dead tagged fish during daily surveys of the entire creek. The relative frequencies of large, medium-sized, and small salmon killed by bears indicated that the risk of predation was more than 150% greater for large than for small salmon. A higher proportion of the male salmon population was killed and a greater proportion of male bodies were consumed than female salmon. Selectivity for male salmon increased as the spawning season progressed, possibly because male salmon weakened earlier and lived longer in a weakened state than female salmon. Male salmon were attacked mostly along the dorsal hump area, whereas female salmon tended to be attacked along the abdomen, where eggs could be exposed. Bears selectively killed female salmon prior to spawning during 1 of the 3 years, but only 6.1–7.8% of the female spawning populations were killed prior to spawning. These data support the hypothesis that selective predation by bears may influence the body morphology of spawning salmon.

Effects of Androgens, Estrogens, and Cortisol on the Skin, Stomach, Liver, Pancreas, and Kidney in Gonadectomized Adult Sockeye Salmon (Oncorhynchus nerka)

1971 ◽  
Vol 28 (4) ◽  
pp. 485-490 ◽  
Author(s):  
J. R. McBride ◽  
A. P. van Overbeeke
Keyword(s):  
Islets Of Langerhans ◽  
Sockeye Salmon ◽  
Pacific Salmon ◽  
Oncorhynchus Nerka ◽  
Skin Atrophy ◽  
Histological Changes ◽  
Male And Female ◽  
Liver And Kidney ◽  
Marked Atrophy

A study was made of the histological changes occurring in the skin, stomach, liver, pancreas and kidney of adult gonadectomized male and female sockeye salmon in response to hormone treatments. The males received 11-ketotestosterone, 17α-methyltestosterone or cortisol for 4 or 7 weeks, and the females received estradiol, estradiol cypionate, or cortisol for 8 weeks.In the males, androgen injection evoked a highly significant increase in the thickness of the epidermis, a marked atrophy of the stomach, and a degeneration in the liver and kidney. In the pancreas, the exocrine portion showed characteristics of cytolysis in the acini, whereas the islets of Langerhans were hypertrophied. These changes were generally more pronounced after 7 weeks than after 4 but, in the skin, no further increase in the thickening of the epidermis was noted after the 4th week of treatment. No differences between responses of these tissues to 11-ketotestosterone and 17α-methyltestosterosne were detected.Estrogen administration in the females evoked similar, albeit weaker, responses in the skin, stomach, pancreas, and kidney than those recorded in the androgen-treated males. The liver of the females exhibited the characteristics of a hyperactive organ, which probably reflects estrogen-induced vitellogenesis.The effects of cortisol were similar in both sexes: little, if any, change was noted in the skin; atrophy or degeneration was observed in the stomach, liver, kidney, and in the exocrine portion of the pancreas, and the islets of Langerhans were hypertrophied. The cortisol-induced alterations were not, however, as pronounced as those noted in either the androgen- or estrogen-treated fish.These changes are discussed in relation to the changes observed in normal sexually maturing and reproducing Pacific salmon.

scholarly journals Implications of a warming eastern Bering Sea for Bristol Bay sockeye salmon

2011 ◽  
Vol 68 (6) ◽  
pp. 1138-1146 ◽  
Author(s):  
Edward V. Farley ◽  
Alexander Starovoytov ◽  
Svetlana Naydenko ◽  
Ron Heintz ◽  
Marc Trudel ◽  
...  
Keyword(s):  
Bering Sea ◽  
Sockeye Salmon ◽  
Large Scale ◽  
Pacific Salmon ◽  
Bristol Bay ◽  
Eastern Bering Sea ◽  
New Information ◽  
Energy Stores ◽  
Overwinter Mortality ◽  
Dependent Processes

Abstract Farley, E. V., Starovoytov, A., Naydenko, S., Heintz, R., Trudel, M., Guthrie, C., Eisner, L., Guyon, J. R. 2011. Implications of a warming eastern Bering Sea for Bristol Bay sockeye salmon. – ICES Journal of Marine Science, 68: 1138–1146. Overwinter survival of Pacific salmon (Oncorhynchus sp.) is believed to be a function of size and energetic status they gain during their first summer at sea. We test this notion for Bristol Bay sockeye salmon (O. nerka), utilizing data from large-scale fisheries and oceanographic surveys conducted during mid-August to September 2002–2008 and from February to March 2009. The new data presented in this paper demonstrate size-selective mortality for Bristol Bay sockeye salmon between autumn and their first winter at sea. Differences in the seasonal energetic signatures for lipid and protein suggest that these fish are not starving, but instead the larger fish caught during winter apparently are utilizing energy stores to minimize predation. Energetic status of juvenile sockeye salmon was also strongly related to marine survival indices and years with lower energetic status apparently are a function of density-dependent processes associated with high abundance of juvenile sockeye salmon. Based on new information regarding eastern Bering Sea ecosystem productivity under a climate-warming scenario, we hypothesize that sustained increases in spring and summer sea temperatures may negatively affect energetic status of juvenile sockeye salmon, potentially resulting in increased overwinter mortality.

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.

Homing in Wild Sockeye Salmon (Oncorhynchus nerka) Populations as Inferred from Differences in Parasite Prevalance and Allozyme Allele Frequencies

1987 ◽  
Vol 44 (11) ◽  
pp. 1963-1971 ◽  
Author(s):  
T. P. Quinn ◽  
C. C. Wood ◽  
L. Margolis ◽  
B. E. Riddell ◽  
K. D. Hyatt
Keyword(s):  
British Columbia ◽  
Sockeye Salmon ◽  
Pacific Salmon ◽  
Oncorhynchus Nerka ◽  
Genetic Differences ◽  
Allele Frequencies ◽  
Wild Populations ◽  
Central Coast ◽  
Barkley Sound ◽  
Quantitative Estimates

Although it is widely accepted that adult Pacific salmon (Oncorhynchus spp.) spawn in their natal stream, there are few quantitative estimates of homing precision in wild populations. The prevalence of two myxosporean parasites, Myxobolus neurobius and Henneguya salminicola, indicated very precise homing in certain sockeye salmon (O. nerka) populations in British Columbia (Long and Owikeno lakes on the central coast and Sproat, Great Central, and Henderson lakes on Barkley Sound, Vancouver Island). These populations were also sampled for electrophoretic differences at 23 loci. Genetic differences were found among all five populations, and estimates of straying from these data corroborated the parasitological evidence that straying is rare (< 1%).

Patterns of Interannual Variation in Age at Maturity of Sockeye Salmon (Oncorhynchus nerka) in Alaska and British Columbia

1985 ◽  
Vol 42 (10) ◽  
pp. 1595-1607 ◽  
Author(s):  
Randall M. Peterman
Keyword(s):  
British Columbia ◽  
Life Histories ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Comparative Approach ◽  
Age At Maturity ◽  
Bristol Bay ◽  
Freshwater Environment ◽  
Marine Life ◽  
Alternative Hypotheses

Interannual variations in mean age of maturity tend to be positively correlated among 10 stocks of sockeye salmon (Oncorhynchus nerka) which spawn in rivers emptying into Bristol Bay, Alaska. Taking a comparative approach, I utilized data from British Columbia and Alaska sockeye stocks with different life histories to test alternative hypotheses about sources of these variations in mean age at maturity. The hypotheses included freshwater environment, marine environment, and parental influences. Freshwater hypotheses were rejected and while some parental effects do exist, they are small compared with the effect of events in early marine life. Early marine growth rate data do not exist for these stocks but evidence from five other sockeye stocks shows that fast growth during this period tends to lead to earlier age at maturity.

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