Precocious Male Atlantic Salmon Parr (Salmo salar) in Insular Newfoundland

1983 ◽  
Vol 40 (5) ◽  
pp. 647-652 ◽  
Author(s):  
E. L. Dalley ◽  
C. W. Andrews ◽  
J. M. Green
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Distribution Patterns ◽  
Sexual Precocity ◽  
Adult Females ◽  
Precocious Males ◽  
Related Distribution ◽  
Salmon Parr ◽  
Immature Fish ◽  
Atlantic Salmon Parr

The incidence of sexual precocity in male Atlantic salmon parr (Salmo salar) was examined in selected rivers in insular Newfoundland from 1974 to 1977. The incidence was variable but generally high, particularly in eastern rivers. Examination of age-specific lengths revealed that the faster growing males became precocious but percent precocity for these varied among river systems. Precocity did not influence growth of parr in comparison to immatures up to the smolt stage. No difference was found in the condition (using gutted weights) of mature and immature parr. However, condition deteriorated in precocious fish compared to immature fish with smoltification. Parr sex ratios frequently differed significantly from 1:1. Possible reasons are discussed in terms of sex related distribution patterns and mortality of precocious parr. From smolt runs examined, it appears that too few precocious parr migrate as smolt to contribute to the grilse population. As a result of the high mortality, rivers with a high percentage of sexually precocious males tend to have a corresponding high percentage of adult females.

Using 137Cs to measure and compare bioenergetic budgets of juvenile Atlantic salmon (Salmo salar) and brook trout (Salvelinus fontinalis) in the field

1999 ◽  
Vol 56 (5) ◽  
pp. 875-887 ◽  
Author(s):  
S Tucker ◽  
J B Rasmussen
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Growth Rates ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Precocious Males ◽  
Annual Consumption ◽  
Consumption Rates ◽  
Salmon Parr ◽  
Atlantic Salmon Parr

Through the 137Cs mass balance method, annual consumption rates were estimated for juvenile Atlantic salmon (Salmo salar) parr and precocious males as well as for brook trout (Salvelinus fontinalis) at four sites in the Ste-Marguerite River system, Québec. With explicit age analysis, consumption rates and growth rates were derived on an individual fish and age-class basis. These represent the first consumption estimates for Atlantic salmon in the wild. Precocious males had consumption rates 1.5 times greater than nonmaturing parr, while Atlantic salmon parr consumption rates were 2.7 times greater than brook trout. There was a strong positive relationship between individual annual consumption and growth rates for Atlantic salmon and brook trout at all sites. Subsequently the concept of field maintenance ration was introduced as the intercept of consumption over growth. Maintenance rations for Atlantic salmon parr ranged from 0.010 to 0.016 g·g-1·day-1 between sites. Brook trout had maintenance rations approximately half those of Atlantic salmon at 0.0059 g·g-1·day-1. Precocious male growth efficiencies were half those of nonmaturing parr despite higher feeding and growth rates. Brook trout growth efficiencies were significantly greater than those of Atlantic salmon parr. The lower growth efficiencies observed for Atlantic salmon are likely due to increased metabolic costs associated with higher activity. On average, Atlantic salmon parr spent 2.4-fold more energy in activity than brook trout. Atlantic salmon precocious males spent 1.7 times more energy in activity than parr.

Degradation of DDT in Atlantic Salmon (Salmo salar)

1968 ◽  
Vol 25 (11) ◽  
pp. 2321-2326 ◽  
Author(s):  
G. L. Greer ◽  
U. Paim
Keyword(s):  
Atlantic Salmon ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Salmo Salar ◽  
Aqueous Suspensions ◽  
Atlantic Salmon Salmo Salar ◽  
Salmon Parr ◽  
Layer Chromatography ◽  
Atlantic Salmon Parr

As indicated by thin-layer chromatography, hatchery-reared Atlantic salmon parr degraded DDT, absorbed from aqueous suspensions, to DDE and TDE within 9 hr. DDT adsorbed on external surfaces of the salmon was not degraded.

Assessment of the transferability of biological habitat models for Atlantic salmon parr (Salmo salar)

2003 ◽  
Vol 60 (11) ◽  
pp. 1398-1408 ◽  
Author(s):  
J C Guay ◽  
D Boisclair ◽  
M Leclerc ◽  
M Lapointe
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Mathematical Structure ◽  
Habitat Patches ◽  
Suitability Index ◽  
Preference Curve ◽  
Substrate Size ◽  
Salmon Parr ◽  
Predicted Values ◽  
Atlantic Salmon Parr

We assessed the transferability of the habitat suitability index (HSI) and the habitat probabilistic index (HPI) between two rivers. Transferability was measured by the ability of HSI and HPI models developed in the Sainte-Marguerite River to predict the distribution of Atlantic salmon parr (Salmo salar) in the Escoumins River. HSI and HPI were based on the pattern of utilization by fish of water depth, current velocity, and substrate size. HSI was developed using the preference curve approach, and HPI was developed using a multiple logistic regression. Predicted values of HSI and HPI in Escoumins River ranged from 0 (poor habitat) to 1 (excellent habitat). Fish density in habitat patches assigned different HSI or HPI values ranged from 0 to 1 fish·100 m–2. Only HPI adequately predicted local variations in parr density (r2 = 0.84) in habitat patches of Escoumins River. Our results suggest that HSI is less transferable between rivers than HPI. Differences in substrate size between the two rivers is suspected to impede the transferability of the HSI model. We also argue that the mathematical structure of HPI provides a larger degree of flexibility that facilitates its transferability and its potential generalization.

Downstream Movements and Estuarine Residence by Atlantic Salmon Parr (Salmo salar)

1989 ◽  
Vol 46 (9) ◽  
pp. 1466-1471 ◽  
Author(s):  
R. A. Cunjak ◽  
E. M. P. Chadwick ◽  
M. Shears
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Significant Proportion ◽  
River Mouth ◽  
Northwest Coast ◽  
Total Production ◽  
Younger Age ◽  
Mean Size ◽  
Salmon Parr ◽  
Atlantic Salmon Parr

Downstream migrations and estuarine residence by Atlantic salmon (Salmo salar) parr and smolts were studied in a small river on the northwest coast of Newfoundland in 1983 and in 1987. There were large downstream migrations in the spring and small downstream migrations in the fall. The major differences between the two types of migrant were that parr migrated about 1 wk before smolts and at a younger age compared with smolts and while parr remained in the estuary throughout the summer, smoits did not. Modal age and mean size were less for parr sampled in the estuary compared with those sampled at the counting-fence which suggested that the smallest parr were not captured by the fence. The estuarine population of parr represented a significant proportion of the river's total production of salmon. Parr were found throughout the estuary in salinities up to 24 parts per thousand but were most abundant near the river mouth. There was evidence that larger parr became smolts and eventually migrated to sea, but smaller parr probably returned to the river for overwintering. It is clear that estuaries should be included as habitat used for rearing Atlantic salmon.

Increased Growth Rate in Atlantic Salmon Parr (Salmo salar) by Using a Two-Coloured Diet

1987 ◽  
Vol 44 (5) ◽  
pp. 1079-1082 ◽  
Author(s):  
Per Johan Jakobsen ◽  
Geir Helge Johnsen ◽  
Jens Christian Holm
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Diet Group ◽  
Mixed Diet ◽  
Feeding Rates ◽  
Highest Weight ◽  
Food Particles ◽  
Salmon Parr ◽  
Swarm Size ◽  
Atlantic Salmon Parr

Fishes hunting by sight are known to pay a cost of confusion when faced with high densities of uniform food particles. Factors such as swarm size, density, and visual uniformity increase confusion. Therefore, it may be profitable in pisciculture to introduce food particles in low densities or to reduce the uniformity and density of each type of feed pellet. This was tested by feeding Atlantic salmon parr (Salmo salar) brown pellets, yellow pellets, or a mixed diet. Mean growth rates were significantly higher for those fish fed a mixed diet. Of the smaller fish in all groups, those in the mixed diet group showed the highest weight/length ratio. We suggest that small individuals have to pay more attention to conspecifics than do large ones, and thus tolerate less confusion when feeding. Larger individuals, tolerating higher confusion costs, achieve higher feeding rates in high densities of uniform feed pellets.

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