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

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.

1984 ◽  
Vol 41 (5) ◽  
pp. 783-797 ◽  
Author(s):  
Geoffrey T. Evans ◽  
Jake C. Rice ◽  
E. Michael P. Chadwick

A simple model of growth and smolting of Atlantic salmon (Salmo salar) parr in Western Arm Brook (northern Newfoundland) can account for the distributions of ages and lengths of random samples of sea-run smolts collected over 10 yr. The parameters of the model determine growth rate, survival rate, and the length that a parr must attain to smolt at age 3 or 4. The parameters are specific to a year-class, not a calendar year, and vary between year-classes. To account for the observed patterns, it is necessary to assume that the criterion length for smolting is different for age 3 and age 4 parr. The variation between year-classes is as great for the criterion length for an age 3 smolt as for the expected length of an age 3 parr, and similarly for age 4. The best estimate of survival rate generally does not vary between year-classes.


1994 ◽  
Vol 72 (9) ◽  
pp. 1603-1610 ◽  
Author(s):  
Alfredo G. Nicieza ◽  
Felipe G. Reyes-Gavilán ◽  
Florentino Braña

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.


PLoS ONE ◽  
2015 ◽  
Vol 10 (3) ◽  
pp. e0119730 ◽  
Author(s):  
Alejandro P. Gutierrez ◽  
José M. Yáñez ◽  
Steve Fukui ◽  
Bruce Swift ◽  
William S. Davidson

1971 ◽  
Vol 28 (4) ◽  
pp. 537-542 ◽  
Author(s):  
Kendall Warner

Recapture of 165 annual and biennial spawners of landlocked Atlantic salmon (Salmo salar) from 1239 fish tagged on the spawning grounds from 1953 to 1955 at the Fish River Lakes, Maine, showed that jaw-tagged females grew significantly slower than untagged female of identical ages and cycles. For most maturing male salmon, growth increments were not significantly reduced by jaw tagging. A tendency for decreased growth increments with increase in age was apparent for both tagged and untagged fish.Recognizable annuli were formed on the scales of 77–100% of 97 male salmon and of 74–97% of 187 female salmon between tagging and recapture. A significantly smaller percentage of females (74%) than males (100%) at large 1 year and recaptured on the spawning grounds had formed a recognizable annulus, but there was no significant difference between females (86%) and males (91%) recaptured by anglers. The significantly lower annulus recognition for annual female spawners was attributed to their demonstrated slower growth rate and possibly resorption of minimal marginal scale growth.Spawning checks were recognizable on the scales of 69–100% of 97 males and 49–78% of 187 females recaptured. Male salmon recaptured on the spawning grounds formed a significantly higher percentage of recognizable spawning checks than females (both annual and biennial spawners), but there were no significant differences between sexes for angler-recaptured fish. Lower reliability in spawning check recognition for females was attributed to less severe marginal resorption resulting in no spawning check being formed or obliteration of previous spawning checks by resorption of the small amount of marginal scale increment made by some annually spawning females, or both.


2012 ◽  
Vol 69 (11) ◽  
pp. 1817-1826 ◽  
Author(s):  
Bror Jonsson ◽  
Anders G. Finstad ◽  
Nina Jonsson

Field studies have revealed that many ectotherms mature younger and smaller in warmer environments although they grow faster. This has puzzled ecologists because the direct effect of factors that accelerate growth is expected to be larger, not smaller size. We tested this experimentally for Atlantic salmon (Salmo salar) at two winter temperatures and diets. Logistic regression revealed that the probability of maturation during the second year in sea water, relative to the probability of older maturation, increased with temperature and growth rate during the first winter. Also, large size and high condition factor 1 year prior to maturation stimulated maturation. In females, a high lipid diet increased the probability of maturation as one-sea-winter fish, and there were significant interactions between winter temperature and food quality and between body size and condition factor the first autumn in sea water. Thus, if the direct effect of temperature on growth rate is the main effect of warming, salmon are likely to attain maturity younger and smaller. Also, richer food decreased age at maturation in females. This finding has consequences for interpretations of climate change impacts on age at maturity in Atlantic salmon and may also hold for many other ectotherm species.


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