Offspring investment in wild Atlantic salmon (Salmo salar): relationships with smolt age and spawning condition

2012 ◽  
Vol 22 (2) ◽  
pp. 317-321 ◽  
Author(s):  
Tim Burton ◽  
Simon McKelvey ◽  
Dave C. Stewart ◽  
John D. Armstrong ◽  
Neil B. Metcalfe
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Atlantic Salmon Salmo Salar ◽  
Offspring Investment ◽  
Smolt Age

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.

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.

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.

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.

Influence of Parental Smolt Age and Sea Age on Growth and Smolting of Hatchery-Reared Atlantic Salmon (Salmo salar)

1980 ◽  
Vol 37 (9) ◽  
pp. 1379-1386 ◽  
Author(s):  
J. K. Bailey ◽  
R. L. Saunders ◽  
M. I. Buzeta
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Female Parent ◽  
Strongly Correlated ◽  
Lower Mode ◽  
Frequency Distributions ◽  
Threshold Size ◽  
Atlantic Salmon Salmo Salar ◽  
First Maturity ◽  
Smolt Age

Hatchery-reared Atlantic salmon, Salmo salar, consistently developed bimodal length–frequency distributions by the first November following hatch. In a study of 32 hatchery populations involving two year-classes, mean length in the lower mode showed little variation among populations and was not correlated with either the smolt age or sea age at first maturity of their parents. Mean length and the proportion of individuals in the upper mode were both variable among populations and correlated with parental age variables. Large mean length in the upper mode was strongly associated with early smolting male parents and late maturing female parents. The proportion of individuals in the upper mode was more strongly correlated with the age variables of the female parent. Late smolting and early maturing female parents tended to produce relatively greater proportions of fish in the upper mode. The optimum growth rate which produced the greatest proportion of individuals in the upper mode occurred when 8–15% of the total population matured precociously as parr. A threshold size hypothesis for precocious maturation is discussed.Key words: Atlantic salmon, genetics, growth, bimodality, precocious sexual maturation, smoltification

Stock Characteristics and Catches of Atlantic Salmon (Salmo salar) in Quebec, and Newfoundland and Labrador in Relation to Environmental Variables

1981 ◽  
Vol 38 (12) ◽  
pp. 1601-1611 ◽  
Author(s):  
G. Power
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Environmental Variables ◽  
River Discharge ◽  
Life Cycles ◽  
Upstream Migration ◽  
Atlantic Salmon Salmo Salar ◽  
Salmon Stock ◽  
Selection For ◽  
Smolt Age

More than 500 stocks of anadromous Atlantic salmon (Salmo salar) in a natural vigorous state are estimated to exist in Newfoundland and the Quebec–Labrador peninsula. They represent the end result of 6000–13 000 years of natural selection for local conditions and have been subject to relatively little manipulation. Stock characteristics correlating with environmental variables include an inverse relation between smolt age and mean temperature, and smolt age and growing season, and a positive relation between the length of sea life and river discharge. Variations in precipitation and temperature across the area result in different patterns of river discharge. Winter discharge is critically low in the north and salmon are restricted to larger rivers; low summer discharge on the east coast of Newfoundland and in southern Quebec may limit parr territory and hamper adult upstream migration. Because upstream migrations are delayed in years of low rainfall, causing salmon to remain longer in the area of commercial fisheries, salmon catches are generally higher in years of low rain than in wet years. The negative correlation occurs again in the catches of salmon 1, 2, and 7 years after years of low rainfall, but the reasons for this are obscure. Sea and river temperatures confine migration to a very short interval in Ungava and affect life cycles and maturation patterns. Most males spend over 12 mo in freshwater before spawning. Constraints are relaxed further south until high summer temperatures cause selection for early and late running stocks. There is a need for more systematic compilation of salmon stock data particularly over long enough periods to evaluate the effects of climatic variables and management strategies.Key words: Atlantic salmon, stock characteristics, precipitation and catches, temperature, migration

Microstructure and texture of fresh and smoked Atlantic salmon, Salmo salar L., fillets from fish reared and slaughtered under different conditions

2001 ◽  
Vol 32 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Sjofn Sigurgisladottir ◽  
Margret S. Sigurdardottir ◽  
Helga Ingvarsdottir ◽  
Ole J. Torrissen ◽  
Hannes Hafsteinsson
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Atlantic Salmon Salmo Salar
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