Stock-Recruitment Relationship for Atlantic Salmon (Salmo salar) in Newfoundland Rivers

1982 ◽  
Vol 39 (11) ◽  
pp. 1496-1501 ◽  
Author(s):  
E. M. P. Chadwick
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Winter Temperature ◽  
Supportive Evidence ◽  
Atlantic Salmon Salmo Salar ◽  
Egg Deposition ◽  
Class Strength ◽  
Stock Recruitment ◽  
Indian River

A stock-recruitment relationship was developed for Atlantic salmon (Salmo salar) in Western Arm Brook, a small Newfoundland river. Supportive evidence was also found on Indian and Little Codroy, two other Newfoundland rivers. On Western Arm Brook, year-class strength of smolts was correlated (P < 0.01) with egg deposition. On Little Codroy River, smolt year-class strength was correlated (P < 0.01) with potential egg deposition of adults counted as kelt. On Indian River egg to fry survival was correlated (P < 0.01) with winter temperature and discharge. On the basis of these findings, the current recommended egg deposition of 2.4 eggs∙m−2 of parr-rearing habitat was considered inadequate for Newfoundland rivers.Key words: stock-recruitment, Atlantic salmon

Estimated Escapement of Atlantic Salmon (Salmo salar) for Maximum Smolt Production in Rivers of Different Productivity

1979 ◽  
Vol 36 (2) ◽  
pp. 132-140 ◽  
Author(s):  
Philip E. K. Symons
Keyword(s):  
Atlantic Salmon ◽  
Water Temperature ◽  
Salmo Salar ◽  
Fishery Management ◽  
Survival Rates ◽  
Atlantic Salmon Salmo Salar ◽  
Egg Deposition ◽  
Average Maximum ◽  
Game Fish ◽  
Space Requirements

Smolt production at different egg deposition densities is estimated from data on survival rates and space requirements of juvenile Atlantic salmon (Salmo salar) reported in the literature. Average maximum production of smolts is estimated to be approximately 5/100 m2 for 2+ smolts, 2/100 m2 for 3+ smolts, and 1/100 m2 for 4+ smolts. Minimum egg depositions recommended for production of these numbers of smolts are 220/100 m2, 165–220/100 m2, and 80/100 m2 for each age of smolts, respectively. The escapement of adults required to produce these depositions must be estimated from observed average weights of returning females and a reported fecundity of Atlantic salmon between 1650 and 1760 eggs/kg of female. With the exception of Ungava rivers, average smolt age in any particular river can be estimated from the number of days per year on which water temperature reaches or exceeds 7 °C. Key words: fishery resources, fishery management, production (biological), escapement, survival, game fish, freshwater fish, rivers

Effect of Sea-Age on the Reproductive Potential of Atlantic Salmon (Salmo salar) in Eastern Canada

1989 ◽  
Vol 46 (12) ◽  
pp. 2210-2218 ◽  
Author(s):  
R. G. Randall
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Reproductive Potential ◽  
Female Size ◽  
Eastern Canada ◽  
Age Composition ◽  
Atlantic Salmon Salmo Salar ◽  
Egg Deposition ◽  
Different Populations ◽  
Spawning Run

Reproductive potential of Atlantic salmon (Salmo salar), defined as average eggs per fish in the spawning run, varied three-fold both within stocks over time and among stocks from different geographic areas. Eggs per spawner is a function of fecundity, sea-age, proportion of females, and female size; the latter three traits varied significantly among years for salmon in both the Miramichi and Restigouche Rivers, New Brunswick. Because all of the above traits are related to sea-age at maturity, eggs per spawner was significantly correlated with mean sea-age in both rivers (R2 = 0.88 and 0.61, respectively). Among 10 different populations in eastern Canada, reproductive potential was also correlated with sea-age; for mean sea-ages (MSA) ranging from 1.0 to 1.8 yr, reproductive potential (RP) was defined by the power regression: RP = 1831.26 MSA1.30 (R2 = 0.64 P < 0.05). Thus reproductive potential can be estimated for any population for which the sea-age composition of spawners is known. Assuming a target egg deposition rate of 2.4 × 104 eggs per hectare, required spawners varied inversely with reproductive potential among the 10 populations, from five spawners (MSA = 1.75 yr) to 16 spawners (MSA = 1.15 yr) per hectare.

Winter temperature and food quality affect age at maturity: an experimental test with Atlantic salmon (Salmo salar)

2012 ◽  
Vol 69 (11) ◽  
pp. 1817-1826 ◽  
Author(s):  
Bror Jonsson ◽  
Anders G. Finstad ◽  
Nina Jonsson
Keyword(s):  
Growth Rate ◽  
Atlantic Salmon ◽  
Direct Effect ◽  
Salmo Salar ◽  
Food Quality ◽  
Condition Factor ◽  
Sea Water ◽  
Winter Temperature ◽  
Age At Maturity ◽  
Atlantic Salmon Salmo Salar

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.

Spawning of escaped farmed Atlantic salmon, Salmo salar L., in western and northern Scottish rivers: egg deposition by females

1993 ◽  
Vol 24 (5) ◽  
pp. 663-670 ◽  
Author(s):  
J. H. WEBB ◽  
A. F. YOUNGSON ◽  
C. E. THOMPSON ◽  
D. W. HAY ◽  
M. J. DONAGHY ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Atlantic Salmon Salmo Salar ◽  
Egg Deposition ◽  
Farmed Atlantic Salmon

Form and uncertainty in stock–recruitment relations: observations and implications for Atlantic salmon (Salmo salar) management

2010 ◽  
Vol 67 (6) ◽  
pp. 1040-1055 ◽  
Author(s):  
William S.C. Gurney ◽  
Philip J. Bacon ◽  
Eddie McKenzie ◽  
Philip McGinnity ◽  
Julian Mclean ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Environmental Variability ◽  
Extinction Risk ◽  
Management Policy ◽  
Quality Data ◽  
Model Parameters ◽  
Atlantic Salmon Salmo Salar ◽  
Regulatory Processes ◽  
Stock Recruitment

This paper reports an investigation of stock–recruitment relations for Atlantic salmon ( Salmo salar ). We regard these relations as stochastic functions characterized by an expected stock–recruitment relation and deviations from this expectation driven by observational error and uncharacterised environmental variability. We estimate model parameters by standard Bayesian methods. Analysis of the input–output characteristics of segments of the salmon life cycle in the Girnock Burn (Northeast Scotland) reveals two independent regulatory processes, one between ova and fry and the other between fry and smolts. Comparison of stock–recruitment relations for Atlantic salmon in Scotland, Ireland, and Canada, reinforced by an extended series of simulation studies, shows that even when comparatively long time series of high quality data are available, it is frequently difficult to exclude the possibility of low stock depensation — an effect whose implication of enhanced extinction risk implies that precautionary management policy would pay special attention to the posssibility of its occurence. A particular feature of our simulation results is their demonstration that inappropriate combination of distinct subpopulations both increases process noise and distorts the expected stock–recruitment relation, thereby greatly reducing the accuracy of any system identification process.

River-specific target spawning requirements for Atlantic salmon (Salmo salar) based on a generalized smolt production model

1998 ◽  
Vol 55 (1) ◽  
pp. 246-261 ◽  
Author(s):  
G Chaput ◽  
J Allard ◽  
F Caron ◽  
J B Dempson ◽  
C C Mullins ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Maximum Yield ◽  
Production Model ◽  
Risk Averse ◽  
Eastern Canada ◽  
Atlantic Salmon Salmo Salar ◽  
Egg Deposition ◽  
Target Values

Atlantic salmon (Salmo salar) management in eastern Canada is based on ensuring that there is sufficient spawning escapement to meet an egg deposition target that maximizes the production of smolts. Using available egg deposition to smolt production data, we show that the present strategy of basing spawning targets on the presence-absence of lacustrine habitat for the rearing of juvenile salmon is a valid approach. We further show that a general smolt production model that accounts for this difference in available habitat when combined with the biological characteristics of the recruiting adults provides river-specific spawning targets. Targets corresponding to maximum yield tend to be less than half the target values currently used. A target representing the egg deposition for 90% of maximum yield serves as an example of a risk-averse strategy. The lower target values relative to those currently used are in large part determined by low sea survivals. The targets that we derived for four example rivers would correspond to the currently used target egg depositions if the long-term sea survivals were 2-3 times those observed in the last 6 years.

Influence of Seasonal River Discharge on Survival of Juvenile Atlantic Salmon Salmo Salar

1988 ◽  
Vol 45 (2) ◽  
pp. 344-348 ◽  
Author(s):  
R. J. Gibson ◽  
R. A. Myers
Keyword(s):  
Atlantic Salmon ◽  
New Brunswick ◽  
Salmo Salar ◽  
River Discharge ◽  
Positive Relationships ◽  
Atlantic Salmon Salmo Salar ◽  
Juvenile Atlantic Salmon ◽  
Stock Recruitment

The effects of winter and summer river discharge on the survival of eggs and underyearlings of Atlantic salmon (Salmo salar) were examined in six rivers of Newfoundland and New Burnswick where stock–recruitment relationships were available. There were positive relationships between either winter discharge or temperature and survival of underyearling salmon for five rivers. For all rivers combined, survival and winter discharge were related (P < 0.05). The hypothesis that summer discharge was unrelated to survival could not be rejected. However, there was evidence that summer discharge enhances survival in the Miramichi and Northwest Miramichi rivers of New Brunswick.

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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