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.

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.

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.

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.

Isolation and Identification of an Atypical Aeromonas salmonicida Strain Causing Epizootic Losses Among Atlantic Salmon (Salmo salar) Reared in a Nova Scotian Hatchery

1980 ◽  
Vol 37 (12) ◽  
pp. 2236-2241 ◽  
Author(s):  
W. D. Paterson ◽  
D. Douey ◽  
D. Desautels
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Aeromonas Salmonicida ◽  
Biochemical Reactions ◽  
Isolation And Identification ◽  
Cumulative Mortality ◽  
Atlantic Salmon Salmo Salar ◽  
A Value ◽  
Nova Scotian

The bacterium causing 50% cumulative mortality among postyearling parr (pyp) Atlantic salmon (Salmo salar) reared at a Nova Scotian hatchery was identified to be an atypical, achromogenic Aeromonas salmonicida strain. This organism, although differing in several biochemical reactions from typical A. salmonicida, was sensitive to A. salmonicida bacteriophages. Antigenically, the Kejimkujik A. salmonicida was indistinguishable from typical A. salmonicida strains when the serological relatedness was examined using cross-adsorbed rabbit antisera. Analysis of DNA from the atypical A. salmonicida yielded a % GC value of 57.85, a value within the range expected for A. salmonicida.Key words: atypical, Aeromonas salmonicida, Atlantic salmon

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.

Nocturnal activity of juvenile Atlantic salmon (Salmo salar) in late summer: evidence of diel activity partitioning

1997 ◽  
Vol 54 (6) ◽  
pp. 1408-1413 ◽  
Author(s):  
Gabe Gries ◽  
Kevin G Whalen ◽  
Francis Juanes ◽  
Donna L Parrish
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Late Summer ◽  
Diel Activity ◽  
Juvenile Salmon ◽  
Time Budgets ◽  
Nocturnal Activity ◽  
Atlantic Salmon Salmo Salar ◽  
Juvenile Atlantic Salmon ◽  
Young Of The Year

Paired day-night underwater counts of juvenile Atlantic salmon (Salmo salar) were completed on tributaries of the West River, Vermont, U.S.A., between 28 August and 10 September 1995. At water temperatures ranging from 13 to 23°C, the relative count of juvenile salmon was greater at night. Nocturnal counts differed for young-of-the-year and post-young-of-the-year (PYOY) salmon, with PYOY exhibiting almost exclusive nocturnal activity. Nocturnal activity in late summer may enable salmon to maintain population densities when space and suitable feeding areas may be limited. Nocturnal activity of juvenile salmon should be considered in studies of habitat use, competition, time budgets, and associated bioenergetic processes.

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.

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.

Effects of ice on behaviour of juvenile Atlantic salmon (Salmo salar)

2013 ◽  
Vol 70 (10) ◽  
pp. 1488-1497 ◽  
Author(s):  
Tommi Linnansaari ◽  
Richard A. Cunjak
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Nocturnal Activity ◽  
Atlantic Salmon Salmo Salar ◽  
Daytime Activity ◽  
Ice Conditions ◽  
Salmon Parr ◽  
Surface Ice ◽  
Ice Period ◽  
Atlantic Salmon Parr

The behaviour of Atlantic salmon (Salmo salar) parr was compared among three periods of winter (pre-ice period, PI; period of subsurface ice, SSI; period of surface ice, SI). Salmon parr remained nocturnal regardless of the ice conditions. The level of nocturnal activity was similar during PI and SI periods but was significantly reduced during the SSI period. Immobility was also highest during the SSI period, but was only partly attributable to salmon parr being trapped under ice. No differences in daytime activity among ice periods were observed. Two nocturnal movement tactics were observed: (i) “emerge–settle–return” and (ii) “emerge–move–return”. The tactics were used similarly during PI and SSI periods, but the “move” tactic was predominant during the SI period. Atlantic salmon parr showed a strong tendency to return to their “home stone” after a period of activity. Homing was reduced during the SSI period, but the distance moved to a new home stone was typically <10 m. In general, salmon parr were able to cope well with subsurface and surface ice.

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