Effects of population-specific variation in age and length on fishery selection and exploitation rates of sockeye salmon (Oncorhynchus nerka)

2009 ◽  
Vol 66 (6) ◽  
pp. 896-908 ◽  
Author(s):  
Neala W. Kendall ◽  
Thomas P. Quinn
Keyword(s):  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Age Groups ◽  
River System ◽  
Directional Selection ◽  
Size At Maturity ◽  
Natural Processes ◽  
Fishery Exploitation ◽  
Specific Variation ◽  
Complex Variation

Conspecific salmonid populations often differ in age and body size at maturity, and these differences can cause fishery exploitation rates and patterns of directional selection on size to vary among populations. Based on age and length data on five representative spawning populations of sockeye salmon ( Oncorhynchus nerka ) in the Wood River system, Bristol Bay, Alaska, USA, we estimated exploitation rates and population-specific patterns of selection from a gillnet fishery between 1963 and 2007. Exploitation rates have differed among age groups and have varied greatly over time, likely due to changes in fishery selectivity. Populations with older, larger fish were more heavily exploited than populations with small, young fish. Differential fishery selection was detected among the populations, linked to persistent differences in size and age of fish among the populations. Specifically, we found evidence of stronger size selectivity on populations with smaller-bodied fish and less directional selection on populations dominated by larger-bodied fish. These results reveal the complex variation in the intensity and selectivity of fishing that can result from exploitation of populations that differ in age and size at maturity and shape. Evolutionary responses to this selection may be taking place, but natural processes provide countervailing selection.

DIRECTIONAL SELECTION BY FISHERIES AND THE TIMING OF SOCKEYE SALMON (ONCORHYNCHUS NERKA) MIGRATIONS

2007 ◽  
Vol 17 (3) ◽  
pp. 731-739 ◽  
Author(s):  
Thomas P. Quinn ◽  
Sayre Hodgson ◽  
Lucy Flynn ◽  
Ray Hilborn ◽  
Donald E. Rogers
Keyword(s):  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Directional Selection

scholarly journals TRAUMATIZATION BY LAMPREYS OF SOCKEYE SALMON ONCORHYNCHUS NERKA (WALBAUM, 1792) IN THE MEYNYPIL’GYN LAKE-RIVER SYSTEM (KORYAK COAST OF CHUKOTKA)

2019 ◽  
Vol 198 ◽  
pp. 3-18
Author(s):  
E. V. Golub’ ◽  
A. P. Golub’
Keyword(s):  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Russian Far East ◽  
Pink Salmon ◽  
Far East ◽  
River System ◽  
Oncorhynchus Gorbuscha ◽  
Small Fish ◽  
Mean Size ◽  
Arctic Lamprey

Data on traumatization of sockeye salmon Oncorhynchus nerka spawners in the Meynypil’gyn lake-river system by lampreys are presented on results of observations in 1998– 2018. Features and localization of injuries are described comparing the injuries of males and females and biological parameters of fish with and without the injuries. In the Meynypil’gyn lake-river system, relative to other areas of Russian Far East, the portion of fish with injuries from lampreys is medium for sockeye salmon, and low for pink salmon Oncorhynchus gorbuscha and charr Salvеlinus malma. Judging by size of the wounds, the injuries were caused mostly by arctic lamprey Entosphenus tridentatus. Generally, about 68 % of sockeye spawners were attacked by lampreys during their pre-spawning migrations just before entering the fresh waters, but the percentage (P) depends on length (L) of fish: P = 1.2026 . L + 1.2192 (R2 = 0.879). So, the portion of injured fish increased from 2.7 % for the sockeye producers with length < 500 mm to 31.2 % for those with length 671–680 mm. Mean size and weight of the male and female sockeye spawners with traces of lampreys were statistically significantly higher than these parameters for the fish without injuries. The males injured by lampreys were larger than the males without injures in 18 mm and 295 g, the females — in 5 mm and 80 g, on average. Sockeye females had weaker and less numerous damages, so their portion among the fish with 1 injury was 45.4 %, among the fish with 2 injuries — 42.9 %, among the fish with 3 or more injures — 37.0 %. Besides, mean size of the injured sockeye increased with a number of injures and for the groups with 1, 2, and 3 or more injures it was for females: 604, 608, and 613 mm, for males: 655, 667, and 674 mm, respectively. Such dependencies of alive fish traumatization on their size are caused by higher mortality of small fish after lampreys attacks. There is concluded that arctic lamprey affects significantly on sexual and size composition of sockeye spawners in the Meynypil’gyn lake-river system providing selection of fish with larger size and weight, in particular males.

Population Estimates of Sockeye Salmon (Oncorhynchus nerka) in a Fertilized Oligotrophic Lake

1978 ◽  
Vol 35 (6) ◽  
pp. 851-860 ◽  
Author(s):  
D. G. Robinson ◽  
W. E. Barraclough
Keyword(s):  
Survival Data ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Age Groups ◽  
Close Correlation ◽  
Oligotrophic Lake ◽  
Population Estimates ◽  
Good Resolution ◽  
Growth And Survival ◽  
Carry Over

Pelagic juvenile sockeye salmon (Oncorhynchus nerka) populations were studied in Great Central Lake, British Columbia, during 1969–76 to determine the effect of nutrient enrichment upon their growth and survival. Data for population estimates were collected concurrently by a high-frequency echosounder, and a midwater trawl whose efficiency was inversely related to ambient light above about 1.9 × 10−5 lx. Echogram counts supplemented by trawl catches yielded estimates with low variance, good resolution between age-groups, and indicated close correlation between numbers of spawners and resultant progeny within respective treatments. Survival to the fall for the treated 1969–72 brood years averaged 11.65% (range 11.11–12.81%) of potential egg deposition compared to 3.5% for the pretreatment 1968 brood year fish; 2.73 and 6.29% for the posttreatment 1974 and 1975 brood year fish. A carry-over of fertilization effects on the immediate posttreatment 1973 brood year may have induced a cyclic pattern on the survival of the two succeeding year-classes. The relatively consistent annual production of age 0+ sockeye may be due to the inherent stability of inlake spawning and incubation coupled with the low predation rates. The conservative estimate of a 2.5 increase in survival relative to the natural level indicates a positive response to enhanced feeding conditions caused by the fertilization of this oligotrophic lake. Key words: sockeye, survival, Great Central Lake, fertilization, enhancement, acoustic estimates, townet efficiency

A reappraisal of the ocean migration patterns of Fraser River sockeye salmon (Oncorhynchus nerka) by individual-based modelling

1997 ◽  
Vol 54 (4) ◽  
pp. 847-858 ◽  
Author(s):  
E E Walter ◽  
J P Scandol ◽  
M C Healey
Keyword(s):  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
River System ◽  
Spatially Explicit ◽  
Fraser River ◽  
Directional Bias ◽  
Migration Patterns ◽  
Ocean Surface Currents ◽  
Adult Body Weight ◽  
Migratory Patterns

Although sockeye salmon (Oncorhynchus nerka) spend 1-4 years in the ocean and accumulate 99% of adult body weight during this period, their migratory patterns in the Northeast Pacific are not yet well understood. A model of ocean migration based on conjecture from limited catch and tagging data has influenced work in sockeye ecology for the past 20 years. To evaluate this model, we constructed a spatially explicit individual-based model that used ocean surface currents and simple behavioural rules to simulate migration patterns for sockeye from the Fraser River system. We explored several modelled behaviours, including random swimming and swimming with a directional bias during some months. The simulations begin at the time when juveniles leave inside coastal waters and end when return migration begins (a few months before river reentry). We determined that simple undirected swimming for most of the ocean phase (except the first 4 months when smolts are near the coast) provided results that challenged the prevailing model but did not require complex assumptions. The migration patterns generated by these rules compare well both qualitatively and quantitatively with the existing empirical data on British Columbia sockeye distribution and migrations in the ocean.

Late-season mortality during migration of radio-tagged adult sockeye salmon (Oncorhynchus nerka) in the Columbia River

2005 ◽  
Vol 62 (1) ◽  
pp. 30-47 ◽  
Author(s):  
George P Naughton ◽  
Christopher C Caudill ◽  
Matthew L Keefer ◽  
Theodore C Bjornn ◽  
Lowell C Stuehrenberg ◽  
...  
Keyword(s):  
Sockeye Salmon ◽  
Negative Impact ◽  
Oncorhynchus Nerka ◽  
Columbia River ◽  
River System ◽  
Cumulative Effects ◽  
Negative Effects ◽  
Temperature Regimes ◽  
Migration Corridor ◽  
Passage Times

We radio-tagged 577 adult sockeye salmon (Oncorhynchus nerka) returning to the Columbia River in 1997 to determine how migration behaviors were related to migration success in an altered river system. The probability of successful migration declined dramatically for late-entry individuals, concomitant with declines in discharge and the onset of stressful temperatures. Long dam passage times were not related to unsuccessful migration at most dams. However, when migration histories were analyzed across multiple dams or reservoirs, relatively slow migration was significantly associated with unsuccessful migration, suggesting potential cumulative effects. Median passage times at dams were rapid (7.9–33.4 h), although 0.2%–8% of salmon took more than 5 days to pass. Reservoir passage was also rapid, averaging 36.8–61.3 km·day–1, and appeared to compensate for slowed migration at dams. Rates observed in the unimpounded Hanford Reach suggest that total predam migration rates may have been similar to current rates. Overall, our results suggest that cumulative effects may be more important than negative effects of passage at single dams and that hydrosystem alteration of temperature regimes in the migration corridor may have an important indirect negative impact on adults.

Mate Selection in a Population of Sockeye Salmon (Oncorhynchus nerka) of Mixed Age-groups

1967 ◽  
Vol 24 (9) ◽  
pp. 1955-1977 ◽  
Author(s):  
Arthur J. Hanson ◽  
Howard D. Smith
Keyword(s):  
Mate Selection ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Age Groups ◽  
Different Types ◽  
Skeena River ◽  
The Relationship ◽  
Mixed Age

Anadromous Skeena River sockeye mature and spawn mainly at ages 42 and 52. Lesser numbers of 32, 53, and 63 and 64 fish, and non-anadromous kokanee, may spawn in the same stream. Mate selection by the different types was studied by observing salmon of known length and using the relationship found between length and age in dead, spawned fish.Fish of all lengths tended to mate with similar sized fish. Small males were less successful in holding mates than were large males because they could not successfully defend redds against larger intruders. Small males spent more time alone than large ones and frequently lay in groups behind mating pairs. The term "satellite male" is used in describing the behaviour. Small females mated with large males but spent more time alone than did large females.The genetic implications of mating within age-groups are considered.

scholarly journals Age composition of Chukchi sockeye salmon Oncorhynchus nerka

2014 ◽  
Vol 179 (4) ◽  
pp. 10-31
Author(s):  
Elena V. Golub’
Keyword(s):  
Sockeye Salmon ◽  
Natural Habitat ◽  
Age Groups ◽  
River System ◽  
Brood Stock ◽  
Age Composition ◽  
Kokanee Salmon ◽  
Spawning Areas ◽  
Reproductive Part

Long-term data on age composition for Chukchi populations of sockeye salmon are presented. Spawners of 23 ages are recognized in the period 1970-2013 for 10 populations: 2+, 3+, 0.1+, 0.2+, 0.3+, 0.4+, 0.5+, 1.1+, 1.2+, 1.3+, 1.4+, 1.5+, 2.1+, 2.2+, 2.3+, 2.4+, 2.5+, 3.1+, 3.2+, 3.3+, 3.4+, 4.2+, and 4.3+. The brood stock basis is formed by five- and six-year fish of 1-2-year freshwater feeding and 3-year marine feeding. The greatest diversity in the age composition is observed at the northern limit of the Asian sockeye salmon natural habitat - i.e. in the Seutakan and Achchen lake-river systems. The spawners dropped into the sea at the age of 0+ and 1+ years are more common in the populations with prevailing limnophilous forms of sockeye (rivers Khatyrka, Tumanskaya and Anadyr, Seutakan lake-river system), and the spawners dropped at the age 2+ and 3+ years - in the populations with domination of its rheophilous form (Meinypilgyn lake-river system, Orianda and Amaam lagoons). As compared with the sockeye salmon from central spawning areas of the habitat, the Chukchi sockeye has more complicated age composition of reproductive part of stocks, greater duration of marine feeding, females predominance among fast-maturing fish returning after 2 years of marine life, higher portion of males in senior age groups, and minor level of kokanee salmon and jacks. Brief description of spawning and/or feeding ponds for Chukchi sockeye salmon is presented.

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