Growth and survival of Atlantic salmon (Salmo salar) in Llyn Dwythwch, North Wales

1978 ◽  
Vol 8 (5) ◽  
pp. 423-431 ◽  
Author(s):  
R. B. PEDLEY ◽  
J. W. JONES
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Growth And Survival ◽  
Atlantic Salmon Salmo Salar ◽  
North Wales

The effect of porcine somatotropin on growth, and survival in seawater of Atlantic salmon (Salmo salar) parr

1976 ◽  
Vol 54 (4) ◽  
pp. 531-535 ◽  
Author(s):  
M. P. Komourdjian ◽  
R. L. Saunders ◽  
J. C. Fenwick
Keyword(s):  
Growth Hormone ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Growth Hormone Treatment ◽  
Hormone Treatment ◽  
Control Fish ◽  
Growth And Survival ◽  
Atlantic Salmon Salmo Salar ◽  
Porcine Somatotropin

The effects of porcine growth hormone on growth and salinity tolerance were studied in Atlantic salmon (Salmo salar) parr. Fish were held in freshwater at 11.5 °C during June and July under a photoperiod with light to dark periods opposite to the prevailing natural conditions. Fish treated with 1.0 μg/g body weight of growth hormone preparation on alternate days were significantly longer (P <.05), after 4 weeks, than placebo-injected controls. All hormone-injected fish survived transfer to seawater, 30‰ salinity. But under the same conditions, placebo-injected control fish showed a high mortality rate. Growth-hormone treatment caused a darkening of fin margins and a yellowing of the operculae and fin surfaces. The silvering which normally accompanies smoltification was not observed. The role of growth hormone in eliciting these actions and its possible role in the parr–smolt transformation are discussed.

Age at Sexual Maturity in Icelandic Stocks of Atlantic Salmon (Salmo salar)

1983 ◽  
Vol 40 (9) ◽  
pp. 1456-1468 ◽  
Author(s):  
Dennis L. Scarnecchia
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Sexual Maturity ◽  
Physical Factors ◽  
Thermal Gradients ◽  
Ocean Temperature ◽  
Growth And Survival ◽  
Atlantic Salmon Salmo Salar ◽  
Life History Pattern ◽  
Second Year

For Icelandic stocks of Atlantic salmon (Salmo salar) in 77 rivers, the combination of June ocean temperature, length of river ascended by the salmon, discharge of the river in July–September, and latitude explained much of the variation in percentages of grilse — 72% for females and 62% for males. For both sexes, percentage of grilse was directly related to ocean temperature but inversely related to length of river, discharge of river, and latitude. For stocks in 23 Southwest Coast rivers, length of river explained 72% of the variation in percentage of females that were grilse. Females in stocks south of the thermal gradients separating Atlantic from Arctic or Polar water tended to return as grilse; females north of the gradients tended to return after more than one winter at sea. The decline in percentages of grilse clockwise from southwestern to northeastern rivers corresponded closely with the decline in June ocean temperatures between these areas. I hypothesize that the salmon stocks have adapted their age at sexual maturity to the length and discharge of the rivers, natural mortality rates during their second year at sea, and average expected ocean temperatures, reflecting conditions for growth and survival, that the smolts encounter. Age at maturity appears not to be a direct causal response to any of these physical factors, and appears best understood only with reference to the entire life history pattern of each stock.

The marine phase of the Atlantic salmon (Salmo salar) life cycle, with comparisons to Pacific salmon

1998 ◽  
Vol 55 (S1) ◽  
pp. 104-118 ◽  
Author(s):  
L P Hansen ◽  
T P Quinn
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Life Histories ◽  
North Atlantic Ocean ◽  
Pacific Salmon ◽  
Mortality Factor ◽  
Growth And Survival ◽  
Atlantic Salmon Salmo Salar ◽  
The North ◽  
Wide Range

Atlantic salmon (Salmo salar) are distributed over large areas in the north Atlantic Ocean. They usually move very quickly from freshwater to oceanic areas, whereas there is considerable variation among Pacific salmon in early marine movements. In some areas, Atlantic salmon of exploitable size are sufficiently abundant that commercial high seas fisheries have developed. Such areas are off west Greenland, where North American and European fish are harvested, and in the Norwegian Sea, north of the Faroe Islands, where mainly European fish are exploited. Atlantic salmon feed on a wide range of large crustaceans, pelagic fish, and squid in the marine environment, supporting the hypothesis that Atlantic salmon are opportunistic feeders. In the ocean the salmon grow relatively quickly and the sea age when they become sexually mature depends on both genetics and on growing conditions. Natural marine mortality of salmon is highest during the first few months at sea and the major mortality factor is probably predation. However, marine mortality of Atlantic salmon has increased in recent years, apparently correlated with a decline in sea surface temperatures. Similar relationships between environmental conditions and the growth and survival of Pacific salmon have been reported. Atlantic salmon life histories most closely mimic stream-type chinook salmon or steelhead trout among the Pacific species. Finally, Atlantic and Pacific salmon return to their home rivers with high precision and possible mechanisms controlling the oceanic homing migration are presented and discussed.

Interactions of Atlantic salmon (Salmo salar) and trout (Salvelinus fontinalis and Oncorhynchus mykiss) in Vermont tributaries of the Connecticut River

2003 ◽  
Vol 60 (3) ◽  
pp. 279-285 ◽  
Author(s):  
Matthew J Raffenberg ◽  
Donna L Parrish
Keyword(s):  
Atlantic Salmon ◽  
Oncorhynchus Mykiss ◽  
Salmo Salar ◽  
Brook Trout ◽  
Life Histories ◽  
Salvelinus Fontinalis ◽  
Multiple Scales ◽  
Connecticut River ◽  
Growth And Survival ◽  
Atlantic Salmon Salmo Salar

Competitive interactions among stream salmonids in resource-limited environments have been linked to reduced success for many species. Few studies have focused on interactions at scales larger than individual fish or stream reach. We chose to focus our study on these larger scales to provide information for managing species that have complex life histories transcending multiple scales. Our objective was to explore age-0 Atlantic salmon (Salmo salar) growth and survival in relation to trout abundance (introduced rainbow (Oncorhynchus mykiss) and native brook (Salvelinus fontinalis) trout) and prey resources at 24 stream reaches across two Vermont watersheds that flow into the Connecticut River. Simple linear and multilinear regressions were conducted on response and predictor variables related to fish and invertebrate prey. Age-0 Atlantic salmon survival was greatest at the site with highest trout abundance; however, no linear relationships to trout abundance were detected possibly because Atlantic salmon growth and survival were highly variable across sites. In contrast, a positive significant multivariate relationship was identified among age-0 Atlantic salmon survival, the abundance of age-1+ brook trout (i.e., 100–130 mm), and benthic prey abundance. These results suggest that stocking streams based on trout abundance may not increase Atlantic salmon growth and survival during the first summer of life.

Spatial and temporal effects of interspecific competition between Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) in winter

2001 ◽  
Vol 58 (6) ◽  
pp. 1133-1140 ◽  
Author(s):  
A J Harwood ◽  
N B Metcalfe ◽  
J D Armstrong ◽  
S W Griffiths
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Habitat Preferences ◽  
Flowing Water ◽  
Stream Channels ◽  
Growth And Survival ◽  
Atlantic Salmon Salmo Salar ◽  
Brown Trout Salmo Trutta

Previous work has shown that juvenile stream-dwelling salmonids become predominantly nocturnal during winter by emerging from daytime refuges to feed, with several species having been shown to prefer slow-flowing water while active at night. We used seminatural stream channels, landscaped to provide a choice of water depths, and hence velocities, to test whether Atlantic salmon, Salmo salar, and brown trout, Salmo trutta, show similar habitat preferences during winter. We also tested whether there was any spatial or temporal displacement of Atlantic salmon when in sympatry with brown trout. Nighttime observations revealed that Atlantic salmon did have a preference for slow-flowing water. However, when in direct competition with trout, salmon either remained predominantly nocturnal but occupied shallower water, or became significantly less nocturnal, spending more time active during the day than when in allopatry. These results, which were especially marked in relatively larger fish, indicate that competition between the two species for food and resources is not restricted to the summer months and may affect both the short- and long-term growth and survival of overwintering wild Atlantic salmon.

Distribution of Atlantic salmon (Salmo salar) postsmolts of different origins in the Bay of Fundy and Gulf of Maine and evaluation of factors affecting migration, growth, and survival

2005 ◽  
Vol 62 (6) ◽  
pp. 1363-1376 ◽  
Author(s):  
Gilles L Lacroix ◽  
Derek Knox
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Gulf Of Maine ◽  
Fish Larvae ◽  
Surface Current ◽  
Clupea Harengus ◽  
Bay Of Fundy ◽  
Growth And Survival ◽  
Atlantic Salmon Salmo Salar ◽  
Salmon Lice

Atlantic salmon (Salmo salar) postsmolts surveyed by surface trawling in the Bay of Fundy and Gulf of Maine during 2001–2003 were aggregated in several areas in the Bay of Fundy and dispersed over a broader area in the Gulf of Maine. Postsmolt distribution reflected the major surface-current vectors and was independent of origin (wild vs. hatchery, inner vs. outer Bay of Fundy). Migration proceeded without disruption, and marked wild postsmolts from both the inner and outer Bay of Fundy were recaptured in the outer Bay of Fundy and the Gulf of Maine, where their distribution overlapped the commercial fishery for Atlantic herring (Clupea harengus). Marked postsmolts of wild origin were recaptured more frequently than those of hatchery origin but the overall density was low, and no schools of postsmolts were encountered that could offer protection from predators. Temperature and salinity in postsmolt habitat were favourable for growth and survival. Postsmolts were in excellent condition and had no bacterial or viral pathogens or salmon lice (Lepeophtheirus salmonis). They were feeding on pelagic prey (amphipods, euphausiids, and fish larvae) and the period of accelerated marine growth had started, indicating that environmental conditions and food supply were not limiting growth and survival.

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