Density-dependent territory size and individual growth rate in juvenile Atlantic salmon (Salmo salar)

2014 ◽  
Vol 24 (1) ◽  
pp. 15-22 ◽  
Author(s):  
Amanda A. Lindeman ◽  
James W. A. Grant ◽  
Cyndy M. Desjardins
Keyword(s):  
Growth Rate ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Individual Growth ◽  
Territory Size ◽  
Density Dependent ◽  
Atlantic Salmon Salmo Salar ◽  
Juvenile Atlantic Salmon ◽  
Individual Growth Rate

Density-dependent habitat selection by juvenile Atlantic salmon (Salmo salar) in experimental riverine habitats

1999 ◽  
Vol 56 (7) ◽  
pp. 1298-1306 ◽  
Author(s):  
Tammo P Bult ◽  
Stephen C Riley ◽  
Richard L Haedrich ◽  
R John Gibson ◽  
Jan Heggenes
Keyword(s):  
Habitat Selection ◽  
Population Density ◽  
Atlantic Salmon ◽  
Habitat Use ◽  
Salmo Salar ◽  
Implicit Assumption ◽  
Experimental Conditions ◽  
Density Dependent ◽  
Atlantic Salmon Salmo Salar ◽  
Juvenile Atlantic Salmon

We investigated habitat use of Atlantic salmon (Salmo salar) parr in experimental riverine enclosures made up of pool, riffle, and run habitats over a range of densities (0.1-1.25 fish·m-2) to test the implicit assumption in habitat modelling that habitat selection does not change with population density. Results indicated that habitat use changed with population density, with relatively more parr in pools and fewer in runs at higher population densities. Temperature influenced parr distribution, with relatively more parr in runs and fewer in riffles and pools at higher temperatures. Parr distribution was primarily affected by hydromorphological differences among pool, riffle, and run habitats. Effects of population density and temperature on use of pool, riffle, and run habitats were often as large as effects of hydromorphological differences among pool, riffle, and run habitats on fish distributions over the range of temperatures and densities observed. Results varied considerably, despite controlled experimental conditions. We concluded that habitat selection by juvenile Atlantic salmon parr may be density dependent and potentially quite variable.

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.

Are wild populations ideally distributed? Variations in density-dependent habitat use by age class in juvenile Atlantic salmon (Salmo salar)

2008 ◽  
Vol 65 (8) ◽  
pp. 1667-1680 ◽  
Author(s):  
A. Jamie F. Gibson ◽  
Heather D. Bowlby ◽  
Peter G. Amiro
Keyword(s):  
Atlantic Salmon ◽  
Habitat Use ◽  
Salmo Salar ◽  
Habitat Quality ◽  
Normal Function ◽  
Age Classes ◽  
Density Dependent ◽  
Atlantic Salmon Salmo Salar ◽  
Juvenile Atlantic Salmon ◽  
Habitat Gradient

We examined relationships between abundance and habitat use in three age classes of juvenile Atlantic salmon ( Salmo salar ) in the Stewiacke River, Nova Scotia, Canada. Using stream gradient as a proxy for habitat quality, we used a double half normal function, modified to include density dependence, to model the relationship between habitat quality and fish density. We found that density was asymmetrically distributed around a similar optimum gradient for all three age classes regardless of abundance. Habitat use was highly density-dependent for age-0 and age-1 juveniles, but not for age-2+ salmon. As abundance of age-0 and age-1 salmon increased, their relative density decreased in low-gradient habitat and increased in higher-gradient habitat, although their absolute density increased in all stream gradient categories. Variation in habitat use was consistent with ideal free theory for age-1 juveniles in high-gradient habitat, but not in low-gradient habitat. Age-2+ individuals appeared not to modify their distribution among habitats, even though increasing competition changes the relative benefit of low-gradient habitat in terms of resource acquisition. In contrast, age-1 individuals responded to increased competition by modifying their distribution along the habitat gradient, even though this may have slightly reduced an individual’s potential for growth.

scholarly journals Dispersal and density-dependent growth of Atlantic salmon (Salmo salar) juveniles: clumped versus dispersed stocking

2017 ◽  
Vol 74 (9) ◽  
pp. 1337-1347 ◽  
Author(s):  
Eric Blake Brunsdon ◽  
Dylan John Fraser ◽  
William Rundle Ardren ◽  
James William Angus Grant
Keyword(s):  
Growth Rate ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Negative Power ◽  
Growth And Survival ◽  
Density Dependent ◽  
Atlantic Salmon Salmo Salar ◽  
Nesting Sites ◽  
Juvenile Habitat ◽  
Dependent Growth

Dispersal from nesting sites and habitat selection are essential for the fitness of young individuals and shape the distribution, growth, and persistence of populations. These processes are important to consider when releasing young, hatchery-origin fishes into the wild to restore extirpated or depleted populations. By manipulating the density of released young-of-the-year (YOY) Atlantic salmon (Salmo salar), we evaluated the effects of clumped- (releasing all the fish at one location) and dispersed-stocking (releasing the fish evenly over a complete reach) treatments on juvenile habitat use, dispersal, growth, and survival. Across 14 river reaches, clump-stocked YOY density decreased and growth rate increased with distance downstream, whereas dispersed-stocked YOY densities and growth were relatively constant. Overall, density, spatial variance in density, growth, and survival did not differ between these two stocking treatments, likely due to the greater-than-expected mobility of fish in clumped-stocking reaches; YOY dispersed up to 1600 m, with 41% moving over 200 m downstream. As predicted from previous work, growth rate of individual fish was density-dependent, following a negative power curve. Our results provide insights into how the growth and survival of released individuals are altered via stocking treatments, ultimately shaping their distribution and growth rate.

Patterns of Growth and Smolting of Atlantic Salmon (Salmo salar) Parr in a Southwestern Newfoundland River

1985 ◽  
Vol 42 (3) ◽  
pp. 539-543 ◽  
Author(s):  
Geoffrey T. Evans ◽  
Jake C. Rice ◽  
E. Michael P. Chadwick
Keyword(s):  
Growth Rate ◽  
Simple Model ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Growth Rates ◽  
Individual Growth ◽  
Atlantic Salmon Salmo Salar ◽  
Random Samples ◽  
Non Gaussian

A simple model of growth and smolting of Atlantic salmon (Salmo salar) parr, which can account for distributions of ages and lengths of random samples of sea-run smolts in Western Arm Brook, in northern Newfoundland, cannot account for distributions in Little Codroy River, in southwestern Newfoundland. Possible reasons for discrepancies include mortality dependent on growth rates, non-Gaussian growth rate distributions, and variability in individual growth rates. Smolt data do not allow us to reject any of these possibilities. Precocious maturation of male parr does not account for the discrepancies.

Allometric and environmental correlates of territory size in juvenile Atlantic salmon (Salmo salar)

1995 ◽  
Vol 52 (1) ◽  
pp. 186-196 ◽  
Author(s):  
Ernest R. Keeley ◽  
James W. A. Grant
Keyword(s):  
Body Size ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Territory Size ◽  
Environmental Correlates ◽  
Atlantic Salmon Salmo Salar ◽  
Juvenile Atlantic Salmon ◽  
Wide Range ◽  
Body Sizes ◽  
Young Of The Year

We observed juvenile Atlantic salmon (Salmo salar) over a wide range of stream conditions and body sizes to determine the relative importance of environmental factors and body size as predictors of territory size. Defended and foraging areas were virtually identical in size. Eighty-eight percent of the variation in territory size was explained by differences in body size and age; territory size increased with body size, but young-of-the-year salmon had relatively larger territories for their body size than older fish. Territory size was inversely related to food abundance, the only significant environmental correlate of territory size, but food only explained an additional 2% of the variation in territory size. Intruder pressure, visual isolation, and current velocity were not significantly related to territory size. The allometric scaling of territory size was consistent with the hypothesis that Atlantic salmon maintain a maximum daily ration of drift flowing over their territory. Atlantic salmon in Catamaran Brook have larger territories than is reported in the literature for other stream-dwelling salmonids of a similar size.

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