Forecasting Yields of Two-Sea-Winter Atlantic Salmon (Salmo salar) from Icelandic Rivers

1984 ◽  
Vol 41 (8) ◽  
pp. 1234-1240 ◽  
Author(s):  
Dennis L. Scarnecchia
Keyword(s):  
Atlantic Salmon ◽  
Density Dependence ◽  
Salmo Salar ◽  
Critical Period ◽  
Statistical Tests ◽  
First Year ◽  
Regression Equations ◽  
Predictive Regression ◽  
Atlantic Salmon Salmo Salar ◽  
Linear Relationships

To forecast yields of two-sea-winter Atlantic salmon (Salmo salar) from 15 Icelandic rivers, I developed predictive regression equations based on yields of grilse of the same smolt class harvested in the previous year. The relationships were positive and significant (P < 0.05) for all rivers. The logarithm of grilse catch explained 25–85% of the variation in logarithm of two-sea-winter salmon catch the following year. Inasmuch as statistical tests for linearity between the variables were difficult to interpret and showed conflicting conclusions, I consider them inadequate for assessing whether density dependence occurs between grilse and two-sea-winter salmon. Linear or near linear relationships, which imply no density dependence, appear to occur between log grilse and log two-sea-winter salmon yields. The critical period determining run size from a given escapement thus occurs either during the freshwater rearing phase or during the first year the salmon are at sea.

Influence of Sea Temperature upon the Numbers of Grilse and Multi-Sea-Winter Atlantic Salmon (Salmo salar) Caught in the Vicinity of the River Dee (Aberdeenshire)

1985 ◽  
Vol 42 (9) ◽  
pp. 1513-1521 ◽  
Author(s):  
J. H. A. Martin ◽  
K. A. Mitchell
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
The Arctic ◽  
Average Weight ◽  
Regression Equations ◽  
Catch Per Unit Effort ◽  
Data Set ◽  
Sea Temperature ◽  
Atlantic Salmon Salmo Salar ◽  
High Seas

The possible influence of sea temperature upon the age of return of Atlantic salmon (Salmo salar) was examined using the catch and weight data of grilse and multi-sea-winter (MSW) salmon of the Aberdeen Harbour Board caught either within or adjacent to the River Dee (Aberdeenshire). This data set, apart from a 10-yr period of commercial confidentiality, is very suitable because uniformity of effort allowed catch per unit effort to be calculated. Only in the last few years was external pressure (high seas fishing) applied to the system. Various temperature series were examined but the known loci of high seas fishing and the temperature ranges involved suggested that the most relevant series is from the subarctic. Increase in temperature is shown to be associated with larger numbers of fish returning as MSW salmon and fewer as grilse. The average weight of grilse increases with grilse catch numbers. Regression equations for grilse and MSW salmon catch numbers are produced for the period 1877–1972. There is a marked 4-yr periodicity in the grilse catch data. A hypothesis is proposed that the temperature of the subarctic influences the migratory pattern, that fish travel further north into the Arctic/subarctic only during those years when the minimum temperature remains above 2 °C.

Cross-tributary analysis of parr to smolt recruitment of Atlantic salmon (Salmo salar)

2000 ◽  
Vol 57 (8) ◽  
pp. 1607-1616 ◽  
Author(s):  
Kevin G Whalen ◽  
Donna L Parrish ◽  
Martha E Mather ◽  
James R McMenemy
Keyword(s):  
Atlantic Salmon ◽  
Density Dependence ◽  
Linear Function ◽  
Salmo Salar ◽  
Population Level ◽  
The West ◽  
Atlantic Salmon Salmo Salar ◽  
Mature Parr ◽  
Recruitment Variability ◽  
Level Effect

We used estimates of Atlantic salmon (Salmo salar) parr and smolt density, estimated in three tributaries of the West River, Vermont, U.S.A., to determine (i) if smolt recruitment is density dependent or independent of parr density, (ii) if the proportion of parr migrating as smolts and cohort survival differ among tributaries, and (iii) the effect of parr maturity on smolt production and recruitment variability. We found that parr to smolt recruitment was best described with a linear function providing no evidence for density dependence in the recruitment dynamics of parr and smolts at the tributary scale. The proportion of age-1 parr recruiting to age-2 smolts did not systematically differ among tributaries or years (overall mean ± 95% CL: 18 ± 11%, range = 9-37%), and mean age-1 to age-2 survival ranged less than twofold among tributaries (27-46%) and was independent of cohort density. Survival of age-1 mature (39%) and immature (33%) parr was similar, but probability of smolting for mature parr (0.21) was threefold less than for immature parr (0.76). Quantifying smolt recruitment pathways involving parr maturation helped elucidate the population-level effect of parr maturation on smolt production and recruitment variability.

Analysis of Growth of Atlantic Salmon (Salmo salar) in a Small Newfoundland River

1978 ◽  
Vol 35 (1) ◽  
pp. 60-68 ◽  
Author(s):  
E. M. P. Chadwick ◽  
T. R. Porter ◽  
P. Downton
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Survival Rates ◽  
River System ◽  
First Year ◽  
Commercial Fishery ◽  
Atlantic Salmon Salmo Salar ◽  
Dependent Relationship ◽  
Survival Density ◽  
Sea Survival

Growth and sea survival rates decreased with increasing smolt age, with survival being 12, 6, and 3% for 3+, 4+, and 5+ smolt, respectively. All spawning fish were grilse, which suggests that older smolt became large salmon and were thus more vulnerable to the commercial fishery. A density-dependent relationship was observed for 3+ smolt in their 1st yr of growth, but not for older smolt; younger smolt probably spend their juvenile life in a more productive but space-limiting part of the river. Variation between river-system environments may be responsible for the opposing results of studies on Atlantic salmon (Salmo salar) life history. Key words: Salmo salar, growth, sea survival, density dependence, first-year growth, age at smoltification

Does climate during embryonic development influence parr growth and age of seaward migration in Atlantic salmon (Salmo salar)?

2005 ◽  
Vol 62 (11) ◽  
pp. 2502-2508 ◽  
Author(s):  
Nina Jonsson ◽  
Bror Jonsson ◽  
Lars Petter Hansen
Keyword(s):  
Atlantic Salmon ◽  
Water Temperature ◽  
Early Development ◽  
Salmo Salar ◽  
Climatic Conditions ◽  
First Year ◽  
Long Term Effects ◽  
Atlantic Salmon Salmo Salar ◽  
One Year ◽  
First Year Of Life

Climatic conditions experienced by Atlantic salmon (Salmo salar) in their early development appear to affect parr size at the end of the first growth season and age at emigration from the nursery river. North Atlantic Oscillation indices (NAOIs) correlated positively with water temperature (degree-days) and discharge in the River Imsa during winter (January–April) 1976–2002, indicating a significant oceanic influence on the winter conditions in the river. Specific growth rate of Atlantic salmon parr during the first year of life and the proportion of one-year-old smolts correlated positively with water temperature, flow, and NAOI during February–April during the winter of egg incubation, but only NAOI was significant when cross-correlating the two series using a time difference of 1 year. Water temperature correlated significantly with the proportion of salmon cohorts smolting and migrating to sea at age-1. Such long-term effects of climate during early development may be more important than generally recognized.

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

Persistence of Orally Administered Salmonella enterica Serovars Agona and Montevideo in Atlantic Salmon (Salmo salar L.)

2005 ◽  
Vol 68 (7) ◽  
pp. 1336-1339 ◽  
Author(s):  
L. L. NESSE ◽  
T. LØVOLD ◽  
B. BERGSJØ ◽  
K. NORDBY ◽  
C. WALLACE ◽  
...  
Keyword(s):  
Gastrointestinal Tract ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Salmonella Enterica ◽  
Most Probable Number ◽  
Fish Feed ◽  
Internal Organs ◽  
Probable Number ◽  
Atlantic Salmon Salmo Salar ◽  
Gastric Intubation

The objective of our experiments was to study the persistence and dissemination of orally administered Salmonella in smoltified Atlantic salmon. In experiment 1, salmon kept at 15°C were fed for 1 week with feed contaminated with 96 most-probable-number units of Salmonella Agona per 100 g of feed and then starved for 2 weeks. Samples were taken from the gastrointestinal tract and examined for Salmonella 1, 2, 8, 9, 15, and 16 days after the feeding ended. In experiment 2, Salmonella Agona and Montevideo were separately mixed with feed and administered by gastric intubation. Each fish received 1.0 × 108, 1.0 × 106, or 1.0 × 104 CFU. The different groups were kept in parallel at 5 and 15°C and observed for 4 weeks. Every week, three fish in each group were sacrificed, and samples were taken from the skin, the pooled internal organs, the muscle, and the gastrointestinal tract and examined for the presence of Salmonella. The results from the two experiments showed that the persistence of Salmonella in the fish was highly dependent on the dose administered. Salmonella was not recovered from any of the fish that were fed for 1 week with the lowest concentration of Salmonella. In the fish given the highest dose of Salmonella, bacteria persisted for at least 4 weeks in the gastrointestinal tract as well as, to some extent, the internal organs. The present study shows that under practical conditions in Norway, the risk of Salmonella in fish feed being passed on to the consumer of the fish is negligible.

Sign in / Sign up

Export Citation Format

Share Document