Atlantic salmon (Salmo salar) smolt production: the relative importance of survival and body growth

2009 ◽  
Vol 66 (3) ◽  
pp. 471-483 ◽  
Author(s):  
Gregg E. Horton ◽  
Benjamin H. Letcher ◽  
Michael M. Bailey ◽  
Michael T. Kinnison
Keyword(s):  
Atlantic Salmon ◽  
New England ◽  
Salmo Salar ◽  
High Variability ◽  
Body Growth ◽  
Individual Growth ◽  
Relative Importance ◽  
Entire Study ◽  
Atlantic Salmon Salmo Salar ◽  
Cohort Differences

The complex life history of Atlantic salmon ( Salmo salar ) coupled with interacting abiotic and biotic factors leads to extreme demographic variability across the species’ range. Our goal was to evaluate the relative importance of survival and body growth in determining smolt production across space and time. We used passive integrated transponder tags and capture–mark–recapture analyses to estimate survival, emigration, and growth for six cohorts of presmolt Atlantic salmon in two streams (three cohorts per stream) in New England, USA. We observed remarkable among-cohort consistency in mean monthly survival during a 17-month period from age-0+ autumn to age-2+ spring yet high variability in monthly survival over shorter time intervals (seasons). Despite this latter variability, survival did not translate into among-cohort differences in proportions of age-2+ versus age-3+ smolts. Alternatively, the high variability across seasons and cohorts in mean individual growth rate did lead to differences in within-cohort proportions of age-2+ versus age-3+ smolts (regardless of stream). We conclude that in our two small study streams, variability in growth and size impacted smolt age and, ultimately, smolt production. Density-dependent effects on growth at the scale of the entire study site represent a possible mechanism underlying our observations.

Atlantic Salmon (Salmo salar) Stocks and Management Implications in the Canadian Atlantic Provinces and New England, USA

1981 ◽  
Vol 38 (12) ◽  
pp. 1612-1625 ◽  
Author(s):  
Richard L. Saunders
Keyword(s):  
Atlantic Salmon ◽  
New England ◽  
Salmo Salar ◽  
Environmental Influence ◽  
Function Analysis ◽  
Significant Degree ◽  
Growth Patterns ◽  
Point Of View ◽  
Atlantic Salmon Salmo Salar ◽  
Mixed Stock

This paper discusses the diversity of Atlantic salmon (Salmo salar) expressed as anatomical, physiological, and behavioral differences among stocks in the Atlantic Provinces of Canada and New England, USA. Evidence is reviewed for environmental and genetic influence on a number of stock-specific traits. Unique qualities of particular stocks are described. The loss of salmon from much of its former range is documented and discussed in relation to stock characteristics important in rehabilitation efforts. The mixed stock fisheries in Greenland and Newfoundland are considered from the point of view of interception. It is concluded that identification and management of specific stocks in the Greenland fishery are impracticable at present but that identification of North American components, using discriminant function analysis of scale growth patterns and smolt tagging, should be continued. In Newfoundland knowledge gained from tagging studies allows a significant degree of management of stocks from mainland Canada together with those from Newfoundland and Labrador. Since it is impracticable now to manage the fisheries off Greenland and Newfoundland and off the major Canadian Maritimes salmon-producing rivers—the Miramichi, Restigouche, and Saint John—in strict recognition of stocks, it is suggested that it may be possible to characterize an assemblage of like stocks from given areas and to identify and manage for these in large mixed-stock fisheries. Possible impacts of hatchery plantings are discussed in relation to prospects of success and effects on native stocks. It is concluded that we have the biological basis for evaluating likelihood of success and degree of danger to native stocks from extensive plantings of hatchery-reared juvenile salmon and that such evaluation should be conducted when embarking on projects involving use of hatchery-reared fish as part of a major salmon enhancement program in Atlantic Canada.Key words: genetics, environmental influence, rehabilitation, enhancement, interception, hatcheries, aquaculture

scholarly journals Migration of Postsmolt Atlantic Salmon, Salmo salar, Off Northeastern Newfoundland, As Inferred by Tag Recoveries in a Seabird Colony

1988 ◽  
Vol 45 (3) ◽  
pp. 568-571 ◽  
Author(s):  
W. A. Montevecchi ◽  
D. K. Cairns ◽  
V. L. Birt
Keyword(s):  
Nova Scotia ◽  
Atlantic Salmon ◽  
New England ◽  
Salmo Salar ◽  
Atlantic Coast ◽  
Food Samples ◽  
Seabird Species ◽  
Atlantic Salmon Salmo Salar ◽  
Penobscot River ◽  
Migratory Pattern

Northern gannets, Sula bassanus, and possibly other seabird species nesting on Funk Island off northeastern Newfoundland preyed on postsmolt Atlantic salmon, Salmo salar. Salmon comprised less than 1% of 2928 regurgitated food samples collected from gannets at the colony. Ten smolt tags were recovered in and near the gannetry during August or September in 1984 through 1986. The tags were from smolts released 3–4 mo earlier in the Penobscot River (Maine) (n = 7) and one each from the Saint John River (New Brunswick) and the Lower Clyde and LaHave rivers (Nova Scotia). These recoveries provide evidence that postsmolt Atlantic salmon from rivers in New England, the Bay of Fundy, and the Atlantic coast of Nova Scotia migrate off eastern Newfoundland This migratory pattern contrasts with that of postsmolts from the Gulf of St. Lawrence, which tend to move northwards along Newfoundland's west coast and through the Strait of Belle Isle.

scholarly journals The mating brain: early maturing sneaker males maintain investment into the brain also under fast body growth in Atlantic salmon (Salmo salar)

2014 ◽  
Vol 28 (6) ◽  
pp. 1043-1055 ◽  
Author(s):  
Alexander Kotrschal ◽  
Susanne Trombley ◽  
Björn Rogell ◽  
Ioana Brannström ◽  
Eric Foconi ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Body Growth ◽  
Atlantic Salmon Salmo Salar ◽  
Early Maturing ◽  
The Brain

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.

Differentiation in juvenile growth and bimodality patterns between northern and southern populations of Atlantic salmon (Salmo salar L.)

1994 ◽  
Vol 72 (9) ◽  
pp. 1603-1610 ◽  
Author(s):  
Alfredo G. Nicieza ◽  
Felipe G. Reyes-Gavilán ◽  
Florentino Braña
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Growth Rates ◽  
Individual Growth ◽  
Late Winter ◽  
Southern Population ◽  
Northern Spain ◽  
Atlantic Salmon Salmo Salar ◽  
Juvenile Atlantic Salmon ◽  
Modal Group

Juvenile Atlantic salmon, Salmo salar, from two contrasting populations that had been reared under identical conditions differed in freshwater growth rates and the development of bimodality in length–frequency distributions. Segregation by size started at least a month earlier in the northern (River Shin, northern Scotland) than in the southern population (River Narcea, northern Spain). Northern fish initially grew faster and entered the upper modal group at a larger size (about 100 mm) than did southern fish (about 90 mm). However, the percentage of fish in the upper modal group was greater for the southern population and they grew fastest over winter and during the spring leading up to smolting, and were larger at the smolt stage. By late winter, the individual growth rates of upper modal fish were inversely correlated with their body length in December. These results suggest the existence of genetic differences between populations in the expression of growth bimodality in juvenile Atlantic salmon. This may indicate that size and growth rate thresholds determining the developmental pathway associated with age at smolt metamorphosis may vary between populations as a function of both smolt size and expected growth opportunity during winter and spring.

Effects of spawning distribution on juvenile Atlantic salmon (Salmo salar) density and growth

2011 ◽  
Vol 68 (1) ◽  
pp. 43-50 ◽  
Author(s):  
Maxim A.K. Teichert ◽  
Anders Foldvik ◽  
Torbjørn Forseth ◽  
Ola Ugedal ◽  
Sigurd Einum ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Local Density ◽  
Habitat Characteristics ◽  
Individual Growth ◽  
Dominant Factor ◽  
Atlantic Salmon Salmo Salar ◽  
Local Densities ◽  
Spawning Sites

We test whether the spatial distribution of spawning sites in a natural population is related to the density and individual growth rate of juvenile stream-dwelling salmonids. For this purpose, fine-scale data on the spatial distribution of Atlantic salmon ( Salmo salar ) nest sites, juvenile densities and body size, and habitat characteristics were combined. The area of nests summed over reaches of 25 m in length was positively correlated with local young-of-the-year (YOY) densities and was the strongest predictor of local densities. In turn, increased YOY densities were related to slower growth, and YOY density was the strongest predictor of YOY size. Measured habitat variables had little effect on YOY density over the spatial scale examined, which suggests that redistribution of YOY salmon according to habitat preferences was limited. The distribution of spawning sites was therefore the best predictor of local densities and subsequently YOY growth. Thus, during the YOY stage when dispersal is limited, patchy spawning distributions combined with local density-dependence may be the dominant factor responsible for spatial variation in growth.

Long-term consequences of variation in timing and manner of fry introduction on juvenile Atlantic salmon (Salmo salar) growth, survival, and life-history expression

2004 ◽  
Vol 61 (12) ◽  
pp. 2288-2301 ◽  
Author(s):  
Benjamin H Letcher ◽  
Todd Dubreuil ◽  
Matthew J O'Donnell ◽  
Mariska Obedzinski ◽  
Kitty Griswold ◽  
...  
Keyword(s):  
Life History ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Stabilizing Selection ◽  
Fish Introduction ◽  
Poor Growth ◽  
Entire Study ◽  
Atlantic Salmon Salmo Salar ◽  
Prior Residence

We tested the influence of introduction time and the manner of introduction on growth, survival, and life-history expression of Atlantic salmon (Salmo salar). Introduction treatments included three fry stocking times and stream rearing of embryos. Despite poor growth conditions during the early stocking period, early-stocked fish were larger throughout the entire study period, likely the result of prior residence advantage. This interpretation was reinforced by the laboratory study, where early-stocked fish outgrew late-stocked fish when reared together, but not when they were reared separately. In contrast to growth, abundance of stocked fish was greatest for fish stocked during the middle period, and this stocking group produced the greatest number of smolts. Despite smaller size, survival of stream-incubated fish was generally greater than survival of stocked fish. Introduction timing had a pronounced effect on smolt age but a weak effect on extent of parr maturation. Overall, these observations indicate that small differences (~2 weeks) in introduction time can have long-term effects on size, survival, and life-history expression. Results suggest stabilizing selection on introduction times, mediated by the interaction between prior residence (advantage to fish introduced earlier) and habitat suitability (advantage to fish introduced later).

Impacts of episodic acidification on in-stream survival and physiological impairment of Atlantic salmon (Salmo salar) smolts

2009 ◽  
Vol 66 (3) ◽  
pp. 394-403 ◽  
Author(s):  
Stephen D. McCormick ◽  
Amanda Keyes ◽  
Keith H. Nislow ◽  
Michelle Y. Monette
Keyword(s):  
Atlantic Salmon ◽  
New England ◽  
Salmo Salar ◽  
Ion Homeostasis ◽  
High Water ◽  
Connecticut River ◽  
Episodic Acidification ◽  
Atlantic Salmon Salmo Salar ◽  
Wide Range ◽  
Plasma Chloride

We conducted field studies to determine the levels of acid and aluminum (Al) that affect survival, smolt development, ion homeostasis, and stress in Atlantic salmon ( Salmo salar ) smolts in restoration streams of the Connecticut River in southern Vermont, USA. Fish were held in cages in five streams encompassing a wide range of acid and Al levels for two 6-day intervals during the peak of smolt development in late April and early May. Physiological parameters were unchanged from initial sampling at the hatchery and the high water quality reference site (pH > 7.0, inorganic Al < 12 μg·L–1). Mortality, substantial loss of plasma chloride, and gill Na+/K+-ATPase activity, and elevated gill Al occurred at sites with the lowest pH (5.4–5.6) and highest inorganic Al (50–80 μg·L–1). Moderate loss of plasma chloride, increased plasma cortisol and glucose, and moderately elevated gill Al occurred at less severely impacted sites. Gill Al was a better predictor of integrated physiological impacts than water chemistry alone. The results indicate that Al and low pH under field conditions in some New England streams can cause mortality and impair smolt development in juvenile Atlantic salmon and provide direct evidence that episodic acidification is impacting conservation and recovery of Atlantic salmon in the northeastern USA.

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