Inverse Correlation between Ovarian Development of Atlantic Salmon (Salmo salar) Smolts and Sea Age

1987 ◽  
Vol 44 (7) ◽  
pp. 1320-1325 ◽  
Author(s):  
E. Michael P. Chadwick ◽  
Ross R. Claytor ◽  
Claude E. Léger ◽  
Richard L. Saunders
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Significant Positive Correlation ◽  
Ovarian Development ◽  
Fork Length ◽  
Inverse Correlation ◽  
Positive Correlation ◽  
Atlantic Salmon Salmo Salar ◽  
Smolt Age

In order to understand the factors which determine sea age of Atlantic salmon (Salmo salar), ovarian development of smolts was examined in 14 groups which varied in parental sea age, smolt age, and size. Parental sea age of smolts explained most of the variation in ovarian development. Smolts from one-sea-winter parents had a higher percentage of the more advanced oocyte stages in their ovaries, while smolts from two-sea-winter parents had a low percentage, and those from three-sea-winter parents had none. Annual within-stock variation and covariance with freshwater age were not significant. Hatchery-reared smolts had similar ovarian development to their wild counterparts. There was also a significant, positive correlation between fork length of smolts and ovarian development within groups.

scholarly journals Atlantic salmon (Salmo salar) smolt and early post-smolt migration and survival inferred from multi-year and multi-stock acoustic telemetry studies in the Gulf of St. Lawrence, northwest Atlantic

2018 ◽  
Vol 76 (4) ◽  
pp. 1107-1121 ◽  
Author(s):  
Gérald Chaput ◽  
Jonathan Carr ◽  
Jason Daniels ◽  
Steve Tinker ◽  
Ian Jonsen ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Survival Rates ◽  
Fork Length ◽  
Probability Of Survival ◽  
Size Dependent ◽  
Atlantic Salmon Salmo Salar ◽  
Key Points ◽  
Migration Dynamics

Abstract The migration dynamics and inter-annual variation in early at-sea survival of Atlantic salmon (Salmo salar) smolts over 14 years of study are reported for four river populations located in the Gulf of St. Lawrence (Canada). Acoustically tagged smolts were monitored at three points along their migration from freshwater to the Labrador Sea, a migration extending more than 800 km at sea and a period of 2 months. A hierarchical state-space version of the Cormack–Jolly–Seber model was used to estimate apparent survival rates from incomplete acoustic detections at key points. There was a positive size-dependent probability of survival through the freshwater and estuary areas; the odds of survival of a 16 cm smolt were 1.5–1.7 times higher than for a 13.5 cm smolt, length at tagging. Length adjusted (centred to the mean fork length of smolts during the study of 14.6 cm) survivals through the estuary and nearshore waters were estimated to range between 67 and 90% for the two river populations migrating through Chaleur Bay in contrast to lower survival estimates of 28–82% for the two populations from the neighbouring Miramichi Bay. Across the 14 years of study, survival estimates varied without trend for the populations of Chaleur Bay, but declined for the populations migrating through Miramichi Bay. Survival through the Gulf of St. Lawrence was variable but generally high among years and rivers, ranging from 96% day−1 to 99% day−1. Long term, replicated studies at multiple sites using acoustically tagged smolts can provide empirical data to examine hypotheses of the location and timing of factors contributing to smolt and post-smolt mortality of salmon at sea.

Growth and Genetic Variation of Atlantic Salmon (Salmo salar) from Different Sections of the River Alta, North Norway

1986 ◽  
Vol 43 (10) ◽  
pp. 1828-1835 ◽  
Author(s):  
Tor G. Heggberget ◽  
Roar A. Lund ◽  
Nils Ryman ◽  
Gunnar Ståhl
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Growth Patterns ◽  
Lower Growth ◽  
Local Populations ◽  
Atlantic Salmon Salmo Salar ◽  
Lower Growth Rate ◽  
Growth Differences ◽  
North Norway ◽  
Smolt Age

Growth of young Atlantic salmon (Salmo salar) from three different sections of the River Alta was correlated with estimated growth differences among adult salmon caught in corresponding sections of the river. Young salmon grew most quickly each of the three years investigated in the upper section of the river; further downriver, presmolts had a significantly lower growth rate. Growth calculations based on scale samples from adults indicated corresponding river growth patterns from the three sections. Salmon caught in the upper section of the river had significantly lower smolt age (mean 3.92 yr) and better presmolt growth than salmon caught further downriver (mean smolt age in the middle and lower sections was 4.35 and 4.19 yr, respectively). Correlations between growth differences in young and adult salmon suggest that presmolts that have lived their first years in the upper section of the river apparently return there after having been at sea. Genetic analyses of presmolts indicate that local populations exist. Allele frequency differences at three electrophoretically detectable protein loci give independent support for the existence of genetically differentiated local populations within the River Alta.

Differences in Atlantic Salmon, Salmo salar, from North America and Europe

1972 ◽  
Vol 29 (2) ◽  
pp. 179-185 ◽  
Author(s):  
O. L. Nyman ◽  
J. H. C. Pippy
Keyword(s):  
North America ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
North American ◽  
Serum Proteins ◽  
Fork Length ◽  
Anisakis Simplex ◽  
Atlantic Salmon Salmo Salar

Differences in electropherograms produced by serum proteins and liver esterases were used to identify North American and European Atlantic salmon (Salmo salar) caught at sea. Division of salmon according to continent of origin was supported by mean river age, mean fork length, and abundance of the two parasites Anisakis simplex and Eubothrium crassum. Consistent differences in electrophoretic behaviour of serum proteins and liver esterases in salmon from the two continents support the suggestion that salmon from North America and Europe represent different subspecies.

Behaviour and Microhabitat of Young Atlantic Salmon (Salmo salar) during Winter

1988 ◽  
Vol 45 (12) ◽  
pp. 2156-2160 ◽  
Author(s):  
Richard A. Cunjak
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Activity Pattern ◽  
Fork Length ◽  
Nocturnal Activity ◽  
Atlantic Salmon Salmo Salar ◽  
Sediment Compaction ◽  
Mean Diameter ◽  
Nova Scotian ◽  
Water Depths

Underwater observations at two sites along a small Nova Scotian river were carried out between December and April (water temperature range = 0.5–7.0 °C) to describe the winter microhabitat of young Atlantic salmon (Salmo salar). Salmon (5–15 cm fork length) were consistently found hiding beneath rocks (mean diameter = 16.8–23.0 cm) in riffle-run habitats where mean water depths were 40.9–48.9 cm and mean water velocities were 38.7–45.7 cm∙s−1. Many of the salmon were found overwintering within redd excavations. "Home stones" were distributed closer to midstream than to river banks and where sediment compaction was minimal. Monthly collections of fish (ages 1 and 2) indicated that feeding continued over winter. The data suggest a nocturnal activity pattern and photonegative response by young salmon during winter.

Reduction of Atlantic Salmon (Salmo salar) Catches in Canada Attributed to the Greenland Fishery

1974 ◽  
Vol 31 (9) ◽  
pp. 1467-1480 ◽  
Author(s):  
J. E. Paloheimo ◽  
P. F. Elson
Keyword(s):  
Adverse Effect ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Inverse Correlation ◽  
River System ◽  
Detailed Data ◽  
Significant Inverse Correlation ◽  
Atlantic Salmon Salmo Salar ◽  
Spawning Stock

Recaptures of Atlantic salmon (Salmo salar) tagged as smolts show that substantial numbers of those produced in the Maritimes are caught in Greenland waters. Percentage recoveries in the home-river system show a significant inverse correlation with levels of catches in Greenland. Analyses of detailed data collected since 1950 indicate that the Greenland fishery has caused serious reduction of Miramichi stocks of 2-sea-winter salmon and will affect the future long-term production of Atlantic salmon in Canada.Total landings have risen higher per million smolts produced in the Miramichi system since the Greenland fishery began. The escapement from fisheries and the potential spawning stock per given numbers of smolts has dropped correspondingly. Lowered escapement has been followed by lowered abundance of progeny as reflected by density of young in nursery stream areas. Significantly, recruitment as measured in numbers of underyearlings depends more crucially on numbers of salmon escaping the fishery than on numbers of grilse. As shown by this statistical analysis, the Greenland fishery has had a direct adverse effect on the numbers of salmon surviving to enter their spawning river. Consequently, the abundant smolt runs in 1964, 1965, and 1968 produced by good escapement some 4 yr earlier failed to maintain adequate levels of recruitment and have instead been followed by all-time low commercial catches and recruitment of young in rivers.

scholarly journals Allometry of diet selectivity in juvenile Atlantic salmon (Salmo salar)

1997 ◽  
Vol 54 (8) ◽  
pp. 1894-1902 ◽  
Author(s):  
E R Keeley ◽  
JWA Grant
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Fork Length ◽  
Stomach Contents ◽  
Optimal Size ◽  
Atlantic Salmon Salmo Salar ◽  
Paired Samples ◽  
Selective Foraging ◽  
Juvenile Atlantic Salmon ◽  
Prey Length

Juvenile salmonids in streams typically feed on larger invertebrates than the average size available in the drift. Our objective was to describe the allometry of this size-selective foraging in juvenile Atlantic salmon, Salmo salar of Catamaran Brook, New Brunswick. We compared paired samples of the stomach contents of 46 salmon (age 0 + to 2 + ; fork length 2.9-14.5 cm) with drift samples collected from their feeding territories. Juvenile salmon fed opportunistically on all major types of invertebrates in the drift, except for water mites (Hydracarina). However, newly emerged salmon fed on smaller prey than the average available in the drift, primarily chironomid larvae, whereas salmon larger than 4.6 cm fed on larger prey than average, primarily dipteran adults and pupae. Larger salmon ate larger prey. Minimum prey length in stomachs was well predicted by gill raker spacing, but mean prey width was only one third of the optimal size and maximum prey width was much less than mouth width. The allometry of prey size appeared to be related primarily to an increase in size-selective foraging with increasing body size, rather than to morphological constraints. Juvenile Atlantic salmon in our study ate smaller prey than similar-sized salmonids in other studies.

Individual variability in activity patterns of juvenile Atlantic salmon (Salmo salar) in Catamaran Brook, New Brunswick

2007 ◽  
Vol 64 (3) ◽  
pp. 486-494 ◽  
Author(s):  
Cindy Breau ◽  
Laura K Weir ◽  
James WA Grant
Keyword(s):  
Atlantic Salmon ◽  
Water Temperature ◽  
Salmo Salar ◽  
Activity Patterns ◽  
Multiple Logistic Regression Analysis ◽  
Fork Length ◽  
Time Of Day ◽  
Individual Variability ◽  
Atlantic Salmon Salmo Salar ◽  
Yoy Fish

The activity of juvenile salmonids in streams varies between seasons, age classes, and times of day, but few studies have quantified the magnitude of individual variation in the behaviour of wild individuals. We monitored the activity patterns of 35 young-of-the-year (YOY) (fork length: 25.6–34.6 mm) and eight 1+ (fork length: 68.2–78.7 mm) Atlantic salmon (Salmo salar) over an 8-week summer field season. Age 1+ salmon were more active at night than during the day, whereas YOY fish were almost exclusively active during the day. However, daytime activity did not peak at 16–20 °C, the optimal water temperature range for growth determined in laboratory studies. Rather, the activity of 1+ fish peaked at 21 °C, whereas the activity of YOY fish continued to increase until 23 °C and then leveled off between 23 and 27 °C. There was also considerable individual variability within an age class in how fish responded to environmental variables that was often obscured by the average patterns. In a multiple logistic regression analysis for the activity of the 35 YOY, 18 responded significantly to time of day, 17 to water temperature, and 16 to day of the year. The causes of this individual variability and the consequences for growth and mortality deserve further study.

Variation in freshwater growth and development among five New England Atlantic salmon (Salmo salar) populations reared in a common environment

2004 ◽  
Vol 61 (12) ◽  
pp. 2314-2328 ◽  
Author(s):  
Mariska Obedzinski ◽  
Benjamin H Letcher
Keyword(s):  
Atlantic Salmon ◽  
New England ◽  
Salmo Salar ◽  
Growth And Development ◽  
Size Variation ◽  
Phenotypic Trait ◽  
Frequency Distributions ◽  
Atlantic Salmon Salmo Salar ◽  
Intensively Managed ◽  
Smolt Age

We examined phenotypic variation in growth and development from the eyed-egg stage to the age-1+ smolt stage among five New England populations of Atlantic salmon (Salmo salar: East Machias, Narraguagus, Sheepscot, Penobscot, Connecticut) reared in a common laboratory environment. Study populations originated from rivers varying in size, latitude, and level of hatchery supplementation and included one reintroduced population (Connecticut was a recipient of Penobscot origin stock). Phenotypic trait differences were found among populations, and the degree of stock variation depended on ontogeny. Eggs were smaller and hatched sooner in the Penobscot (a northern, intensively managed population), but no stock differences were detected in size or growth efficiency from the onset of exogenous feeding to age 0+ summer. Differences again emerged in age 0+ autumn, with the degree of bimodality in length– frequency distributions differing among stocks; the Connecticut had the highest proportion of upper-mode fish and, ultimately, age-1+ smolts. Although genetic effects could not be entirely separated from maternal effects for egg size variation, it is likely that differences in hatch timing and smolt age had a genetic basis. Early emphasis on age-1+ hatchery-reared smolts in the Connecticut may have led to divergence in smolt age between the Penobscot and Connecticut populations in less than eight generations.

Atlantic Salmon (Salmo salar) of the Leaf River, Ungava Bay

1976 ◽  
Vol 33 (11) ◽  
pp. 2616-2621 ◽  
Author(s):  
R. L.G. Lee ◽  
G. Power
Keyword(s):  
Atlantic Salmon ◽  
Fresh Water ◽  
Salmo Salar ◽  
Sex Ratios ◽  
Fork Length ◽  
Upstream Migration ◽  
Atlantic Salmon Salmo Salar ◽  
Length Range ◽  
Heavy Mortality

The Leaf River supports the most northerly known population of anadromous Atlantic salmon (Salmo salar) in Canada. River growth averaged 40–50 mm/yr, smolts averaged 258 mm fork length (range 190–300 mm) and 5.3 yr (range 4+ to 7+). Many males matured in fresh water and either incurred heavy mortality or became residual. Sex ratios among smolts were 5:1 in favor of females and among adults 3:1 in favor of females. Female 2-sea-winter salmon accounted for 75% of the fresh-run fish. Upstream migration peaked in August: kelts were still resident in the river 11 and 12 mo later.

Life history variation and growth rate thresholds for maturity in Atlantic salmon, Salmo salar

1998 ◽  
Vol 55 (S1) ◽  
pp. 22-47 ◽  
Author(s):  
Jeffrey A Hutchings ◽  
Megan EB Jones
Keyword(s):  
Growth Rate ◽  
Life History ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Optimal Growth ◽  
Age At Maturity ◽  
Early Maturity ◽  
Atlantic Salmon Salmo Salar ◽  
Optimal Growth Rate ◽  
Smolt Age

Based upon published and unpublished data compiled for 275 populations, we describe large-scale spatial and temporal patterns in Atlantic salmon, Salmo salar, life history and model these data to evaluate how changes to life history influence optimal growth rate thresholds for sea age at maturity. Population means (ranges in parentheses) describe the following for salmon throughout its range: smolt length = 14.8 cm (10.5-21.5 cm); smolt age = 2.91 years (1.04-5.85 years); egg-to-smolt survival = 1.5% (0.2-3.2%); grilse length = 56.8 cm (48.5-70.0 cm); sea age at maturity = 1.60 years (1.00-2.64 years); smolt-to-grilse survival = 7.4% (1.3-17.5%). Growth rate thresholds specify the length increase between the smolt and grilse stages above which reproduction after one winter at sea is favoured over later maturity. Our simulations indicated that increased growth generally favours earlier, but never delayed, maturity. Optimal growth rate thresholds for sea age at maturity are highly sensitive to survival but only moderately sensitive to fecundity, smolt size, and smolt age. Depending on an individual's growth rate at sea, early maturity is favoured by decreased smolt age or by increased smolt length, fecundity, or survival (freshwater or marine). We suggest that future Atlantic salmon life history research focus upon reaction norms and growth rate thresholds for age at maturity, demographic and genetic consequences of male parr maturation, and the origin and maintenance of coexisting anadromous and nonanadromous life history polymorphisms.

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