The effect of cloud cover on the development of habitat quality indices for juvenile Atlantic salmon (Salmo salar)

2003 ◽  
Vol 60 (11) ◽  
pp. 1386-1397 ◽  
Author(s):  
Philippe Girard ◽  
Daniel Boisclair ◽  
Michel Leclerc
Keyword(s):  
Grain Size ◽  
Atlantic Salmon ◽  
Water Temperature ◽  
Salmo Salar ◽  
Cloud Cover ◽  
Predictive Power ◽  
Fish Distribution ◽  
Quality Indices ◽  
High Cloud ◽  
Physical Conditions

We tested the validity of the predictions made by a habitat probabilistic index (HPI) developed using a description of the physical conditions (depth, flow velocity, grain size) used and avoided by parrs during days of different cloudiness. Thirteen surveys were designed to estimate the number and the distribution of parrs actively foraging within a 300-m reach of a river. During these surveys, the number of parrs actively foraging ranged from 12 to 118, cloud cover ranged from 5% to 100%, and water temperature ranged from 16.5 °C to 21.7 °C. The number of parrs actively foraging was negatively related to cloud cover (r2 = 0.44 to 0.88) but was independent of water temperature. HPI models developed under low (<33%) and intermediate (34–67%) cloud cover explained 82% to 98% of the local variations of fish density. The HPI model developed under high cloud cover (67–100%) was unable to predict fish distribution observed during cloudy days. Our results suggest that HPI models developed when cloudiness is >67% may have a limited predictive power.

Development and validation of numerical habitat models for juveniles of Atlantic salmon (Salmo salar)

2000 ◽  
Vol 57 (10) ◽  
pp. 2065-2075 ◽  
Author(s):  
J C Guay ◽  
D Boisclair ◽  
D Rioux ◽  
M Leclerc ◽  
M Lapointe ◽  
...  
Keyword(s):  
Logistic Regression ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Water Depth ◽  
Current Speed ◽  
Fish Distribution ◽  
Biological Model ◽  
Habitat Models ◽  
Physical Conditions ◽  
Atlantic Salmon Salmo Salar

We evaluated the ability of numerical habitat models (NHM) to predict the distribution of juveniles of Atlantic salmon (Salmo salar) in a river. NHMs comprise a hydrodynamic model (to predict water depth and current speed for any given flow) and a biological model (to predict habitat quality for fish using water depth, current speed, and substrate composition). We implemented NHMs with a biological model based on (i) preference curves defined by the ratio of the use to the availability of physical conditions and (ii) a multivariate logistic regression that distinguished between the physical conditions used and avoided by fish. Preference curves provided a habitat suitability index (HSI) ranging from 0 to 1, and the logistic regression produced a habitat probabilistic index (HPI) representing the probability of observing a parr under given physical conditions. Pearson's correlation coefficients between HSI and local densities of parr ranged from 0.39 to 0.63 depending on flow. Corresponding values for HPI ranged from 0.81 to 0.98. We concluded that HPI may be a more powerful biological model than HSI for predicting local variations in fish density, forecasting fish distribution patterns, and performing summer habitat modelling for Atlantic salmon juveniles.

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

Temperature-dependent reproduction and survival of Gyrodactylus salaris Malmberg, 1957 (Platyhelminthes: Monogenea) on Atlantic salmon (Salmo salar L.)

Parasitology ◽  
1991 ◽  
Vol 102 (1) ◽  
pp. 105-112 ◽  
Author(s):  
P. A. Jansen ◽  
T. A. Bakke
Keyword(s):  
Atlantic Salmon ◽  
Water Temperature ◽  
Salmo Salar ◽  
Temperature Dependent ◽  
Survival And Reproduction ◽  
Two Temperatures ◽  
The Mean ◽  
Relationship Of ◽  
The Relationship ◽  
Capacity For Increase

SUMMARYThe relationship of survival and reproduction of Gyrodactylus salaris Malmberg on the Atlantic salmon (Salmo salar) to water temperature (2·5–19·0 °C), was studied on the basis of temporal sequence of births and age at death of individual parasites on isolated salmon, and of infrapopulation growth on isolated and grouped salmon. Mean life-span of the parasite was negatively correlated with water temperature: 33·7 days at 2·5 °C and 4·5 days at 19·0 °C. The average number of offspring per parasite peaked between 6·5 and 13·0 °C, and was approximately 2·4 at these two temperatures. Both the period between the successive births of the offspring (max 4) and the estimated generation time were negatively correlated with temperature. The innate capacity for increase (rm) was positively correlated with temperature: from 0·02 (/parasite/day) at 2·5 °C to 0·22 (/parasite/day) at 19·0 °C. Growth of the infrapopulations was positively correlated with water temperature and was higher on isolated fish than on grouped fish, though less than the potential parasite population growth estimated from rm. In the infrapopulations the mean intensity of parasites continued to increase throughout all the experiments on both isolated fish and on grouped fish.

Manipulation of Reproductive Function in Atlantic Salmon (Salmo salar) Kelts with Controlled Photoperiod and Temperature

1992 ◽  
Vol 49 (10) ◽  
pp. 2055-2061 ◽  
Author(s):  
C. E. Johnston ◽  
M. J. Hambrook ◽  
R. W. Gray ◽  
K. G. Davidson
Keyword(s):  
Atlantic Salmon ◽  
Water Temperature ◽  
Salmo Salar ◽  
Reproductive Function ◽  
Spring Water ◽  
Egg Development ◽  
Lower Survival ◽  
Atlantic Salmon Salmo Salar ◽  
Photoperiod Regime

Atlantic salmon (Salmo salar) kelts exposed to a regime of two 6-mo seasonally accelerated light increases and decreases (2CP) in 1989 spawned in the spring of 1990 when water temperatures were above 7 °C during the winter months. Kelts exposed to water temperatures below 4 °C during the same period failed to spawn in the spring. Exposure of the nonspawning 2CP kelts to warmer water temperatures in the summer of 1990 stimulated egg development and ovulation by 17 October 1990. Kelts exposed to a simulated natural 12-mo photoperiod regime also spawned at this time. Eggs and sperm from kelts spawned in the spring were viable. Spring-spawned eggs fertilized with fresh sperm had lower survival levels to the eyed-egg stage or to hatch than did eggs from wild fall-spawned stocks. Kelts entrained to spawn in the spring with 2CP photocycles were manipulated to spawn again in the spring of the next year following exposure to a time-shifted photoperiod and elevated winter/spring water temperature.

scholarly journals Climate Change Impact on Salmon (Salmo salar) and Sea Trout (Salmo trutta) in the Salaca River, Latvia

2020 ◽  
pp. 17-26
Author(s):  
Janis Birzaks
Keyword(s):  
Atlantic Salmon ◽  
Water Temperature ◽  
Salmo Salar ◽  
Salmo Trutta ◽  
Age Groups ◽  
Average Water Temperature ◽  
Sea Trout ◽  
The One ◽  
The Baltic

Hydrometeorological conditions are important determinants of the distribution, abundance and growth of Atlantic salmon (Salmo salar) and sea trout (Salmo trutta) parr and smolt in rivers. Long-term monitoring of the temperate zone Salaca River was conducted to investigate long-term changes in water temperature and streamflow and their effects on juvenile Atlantic salmon and sea trout. The average water temperature in the Salaca River was found to increase over time, particularly in autumn, winter and spring. River discharge increased in winter and summer, which was caused by increased precipitation. Goals of our study were: 1) to examine trends in water temperature and discharge in the river, 2) to explore relations between hydrometeorological trends, on the one hand, and abundance, size at age of salmon and sea trout parr and smolt, as well as changes in smolt migration patterns, on the other. This was the first occasion that a study of this type had been carried out in the Baltic Sea basin. In summer, growth of salmon parr in all age groups in the Salaca River was reduced. However, the size of smolt was found to increase. Migration of sea trout smolt in the Salaca River took place earlier, and the end of both salmon and sea trout migration was also observed earlier. The age structure of salmon smolt changed, with the one-year- old age group dominating. Judging from the total numbers of salmon and sea trout smolt in the River Salaca, production of smolt in the river during the monitoring period increased.

Phytosterols are not involved in the development of fatty liver in plant oil fed Atlantic salmon (Salmo salar) at high or low water temperature

Aquaculture ◽  
2017 ◽  
Vol 480 ◽  
pp. 123-134 ◽  
Author(s):  
Nini H. Sissener ◽  
Nina S. Liland ◽  
Elisabeth Holen ◽  
Ingunn Stubhaug ◽  
Bente E. Torstensen ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Fatty Liver ◽  
Water Temperature ◽  
Salmo Salar ◽  
Plant Oil ◽  
Atlantic Salmon Salmo Salar
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