Plasma ionic composition of the Atlantic salmon (Salmo salar), white sucker (Catostomus commersoni), and alewife (Alosa pseudoharengus) in some acidic rivers of Nova Scotia

1985 ◽  
Vol 63 (10) ◽  
pp. 2254-2261 ◽  
Author(s):  
Gilles L. Lacroix
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Ovarian Development ◽  
Ionic Composition ◽  
Alosa Pseudoharengus ◽  
White Sucker ◽  
Hematocrit Level ◽  
Catostomus Commersoni ◽  
Atlantic Salmon Salmo Salar ◽  
Laboratory Models

Atlantic salmon (Salmo salar) smolts migrating from two acidic rivers (pH 4.9 and 5.2) had high hematocrit levels (> 50%) and low plasma [Cl−] (< 100mequiv. L−1). The hematocrit level was 10% higher and plasma [Na+] was 17% lower in smolts of the more acidic of the two rivers. Salmon parr in rivers of mean pH 5.0, 5.4, and 6.0 over a 7-month period had high hematocrit levels (> 40%) and low plasma [Cl−] (< 125 mequiv. L−1). Plasma [Na+] and [Cl] were both slightly less (~ 5%) and plasma [K+] was higher (> 1.5 times) in parr from the river of pH 5.0 than in those from the other two rivers. Atlantic salmon smolts were more sensitive to low pH (plasma [Na+] 14% less, [Cl] 17% less, and hematocrit level 37% higher) than parr, and parr of the 0+ age-class were more sensitive (plasma [Na+] 9% less) than 1+ parr. Prespawning white suckers (Catostomus commersoni) and alewives (Alosa pseudoharengus) migrating in a river at pH 4.9 had high hematocrit levels and low plasma [Cl−], and alewives (hematocrit, 66%; plasma [Cl], 65 mequiv. L−1) were more severely affected than suckers (hematocrit, 42%; plasma [Cl−], 91 mequiv. L−1). Plasma [Ca2+] in females of both species was not greatly elevated relative to males (female/male [Ca2+] = 1.21 in suckers and 1.14 in alewives), suggesting a possible impairment of calcium metabolism associated with ovarian development. The physiological effects observed in fish inhabiting soft waters (external [Ca2+] < 0.10 mequiv. L−1) at pH levels of about 5.0 generally correlated well with the laboratory "models" of acid exposure in soft water.

Inverse Correlation between Ovarian Development of Atlantic Salmon (Salmo salar) Smolts and Sea Age

1987 ◽  
Vol 44 (7) ◽  
pp. 1320-1325 ◽  
Author(s):  
E. Michael P. Chadwick ◽  
Ross R. Claytor ◽  
Claude E. Léger ◽  
Richard L. Saunders
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Significant Positive Correlation ◽  
Ovarian Development ◽  
Fork Length ◽  
Inverse Correlation ◽  
Positive Correlation ◽  
Atlantic Salmon Salmo Salar ◽  
Smolt Age

In order to understand the factors which determine sea age of Atlantic salmon (Salmo salar), ovarian development of smolts was examined in 14 groups which varied in parental sea age, smolt age, and size. Parental sea age of smolts explained most of the variation in ovarian development. Smolts from one-sea-winter parents had a higher percentage of the more advanced oocyte stages in their ovaries, while smolts from two-sea-winter parents had a low percentage, and those from three-sea-winter parents had none. Annual within-stock variation and covariance with freshwater age were not significant. Hatchery-reared smolts had similar ovarian development to their wild counterparts. There was also a significant, positive correlation between fork length of smolts and ovarian development within groups.

Influence of Varying pH and some Inorganic Cations on the Perivitelline Potential of Eggs of Atlantic Salmon (Salmo salar)

1984 ◽  
Vol 41 (7) ◽  
pp. 1066-1069 ◽  
Author(s):  
R. H. Peterson
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Incubation Medium ◽  
Ambient Medium ◽  
Ionic Composition ◽  
Potential Difference ◽  
Nernst Equation ◽  
Inorganic Cations ◽  
Atlantic Salmon Salmo Salar ◽  
Perivitelline Fluid

A potential difference is maintained between the perivitelline fluid of the Atlantic salmon (Salmo salar) egg and the incubation medium. The magnitude of this potential difference depends on the ionic composition of the incubation medium; it exhibits a maximal negativity in deionized water, then depolarizes, and finally reverses in sign as the ionic content of the incubation medium is raised. The potential difference obeys the Nernst relationship over a limited concentration range of H+, Ca2+, and Mg2+ (10−5 to 10−3M). The maximal change in potential difference with change in Na+ and K+ concentrations is less than that predicted by the Nernst equation. The potential difference permits calculation of the degree of concentration of cations in the perivitelline fluid over that of the ambient medium. Depolarizing the perivitelline potential by lowering the ambient pH will result in losses of other cations from the perivitelline fluid.

Behavior and Growth of Juvenile Atlantic Salmon (Salmo salar) and Three Competitors at Two Stream Velocities

1976 ◽  
Vol 33 (12) ◽  
pp. 2766-2773 ◽  
Author(s):  
P. E. K. Symons
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Open Water ◽  
Catostomus Commersoni ◽  
Atlantic Salmon Salmo Salar ◽  
Juvenile Atlantic Salmon ◽  
Rhinichthys Atratulus ◽  
Blacknose Dace ◽  
Sexually Mature ◽  
Laboratory Stream

In a laboratory stream juvenile Atlantic salmon (Salmo salar), common shiners (Notropis comutus), blacknose dace (Rhinichthys atratulus), and white suckers (Catostomus commersoni) apparently preferred habitats that simulated their natural ones. Only salmon and one sexually mature male shiner defended territories. Dace were gregarious and nomadic, shiners tended to school in open water, and suckers were asocial bottom browsers.No competitive advantage or disadvantage was apparent between species in capturing drift food and growing at fast and slow stream velocities. However, salmon, because of their aggressive territorial behavior, successfully competed for and reduced presence of other species in their preferred boulder habitat.

Effects of Low Environmental pH on the Survival, Growth, and ionic Composition of Postemergent Atlantic Salmon (Salmo salar)

1985 ◽  
Vol 42 (4) ◽  
pp. 768-775 ◽  
Author(s):  
Gilles L. Lacroix ◽  
D. James Gordon ◽  
Dana J. Johnston
Keyword(s):  
Nova Scotia ◽  
Atlantic Salmon ◽  
River Water ◽  
Salmo Salar ◽  
Ionic Composition ◽  
Low Ph ◽  
Atlantic Salmon Salmo Salar ◽  
Flow Through ◽  
Composition Changes

Postemergent Atlantic salmon (Salmo salar) were reared during the early feeding phase in the soft, acidic water of the Westfield River (mean pH 5.0) in Nova Scotia. The fry were held in a flow-through system of tanks in situ and were fed a hatchery diet. Bioassays were also conducted in river water treated with limestone (mean pH 6.1) to provide a control. Cumulative mortality of fry after 30 d in the tanks was 70% at pH 5.0 and only 4% at pH 6.1. Fry in untreated river water were inactive, ingested little food, and lost weight (approximately 25%) during the first 15 d of exposure. Large increases in body [Ca2+] and [Na+] were observed in fry at both pH levels during that time, but the increase in [Ca2+] lagged and that in [Na+] was less in fry at low pH. Deaths occurred 15–30 d after swim-up and dead fry were all severely emaciated, indicating that deaths were probably from starvation. Although there were differences in ionic composition changes in fry held at pH 5.0 compared with control, no major depletion of body ionic reserves occurred relative to initial concentrations. Surviving fry at pH 5.0 developed a tolerance after 25 d and had growth rates, condition factors, and ionic concentrations similar to those of fry in treated water. The mortality of fry during the transition to exogenous feeding, in response to low pH stress in soft water, is probably responsible for reduced recruitment and the decline or loss of salmon stocks in this and other acidic rivers of Nova Scotia.

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.

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