Potential for dispersal of Gyrodactylus salaris (Platyhelminthes, Monogenea) by sea-running stages of the Atlantic salmon (Salmo salar): field and laboratory studies

1998 ◽  
Vol 55 (2) ◽  
pp. 507-514 ◽  
Author(s):  
Arnulf Soleng ◽  
Tor A Bakke ◽  
Lars P Hansen
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
River Mouth ◽  
Infected Fish ◽  
Surface Salinity ◽  
Wild Salmon ◽  
Atlantic Salmon Salmo Salar ◽  
Water Dispersal ◽  
Salmon Parr ◽  
Salmon Smolt

Population growth of Gyrodactylus salaris increased exponentially on Atlantic salmon (Salmo salar) smolts in laboratory experiments conducted at 12.0°C. Furthermore, G. salaris was transmitted successfully from salmon smolt to parr at 0.0, 7.5, 10.0, and 20.0%° salinity and reproduced in fresh water after direct transfer from 7.5%° (16 days), 20.0%° (4 and 8 h), and 33.0%° (5, 15, and 30 min). No G. salaris were observed on salmon parr exposed to 33.0%° for 60 min. The prevalence of G. salaris on wild salmon smolts caught approximately 25 km from the river mouth in the Drammensfjord (surface salinity 2.0-3.5%°) was 71.2% compared with 88.0% on those from the neighbouring River Lierelva. Adult wild salmon caught as prespawners, spawners, and postspawners (kelts) in the River Drammenselva were infected with G. salaris. The prevalence and abundance increased from autumn to spring, in contrast with earlier studies on salmon parr, demonstrating the possible importance of adult salmon as reservoirs for G. salaris during winter. The results support the hypothesis of brackish water dispersal of G. salaris by infected salmonids migrating in estuaries and fjords. The use of salt as a disinfectant against G. salaris in hatcheries, and the stocking of possibly infected fish into brackish and seawater, should also be reexamined.

Feeding by Hatchery-Reared and Wild Atlantic Salmon (Salmo salar) Parr in Streams

1979 ◽  
Vol 36 (11) ◽  
pp. 1408-1412 ◽  
Author(s):  
A. J. Sosiak ◽  
R. G. Randall ◽  
J. A. McKenzie
Keyword(s):  
Atlantic Salmon ◽  
Key Words ◽  
Salmo Salar ◽  
Food Selection ◽  
Stomach Contents ◽  
Stomach Fullness ◽  
Size Dependent ◽  
Atlantic Salmon Salmo Salar ◽  
Feeding Experience ◽  
Salmon Parr

Hatchery-reared Atlantic salmon (Salmo salar) parr were captured 1–3 mo after release in streams, along with wild parr from the same streams. Identification of their stomach contents showed total number of organisms and number of taxa per stomach were greater and there was a higher index of stomach fullness in wild than in hatchery parr resident ≤ 2 mo in a stream. Wild parr consumed more Brachycentridae, Hydroptilidae, Diptera, and Plecoptera than did hatchery parr, but sometimes less Odontoceridae and Heptageniidae. These differences may have arisen from size-dependent food selection, the effects of feeding experience, or possible microhabitat differences between wild and hatchery parr. Key words: salmon parr, hatchery-reared, wild, feeding

Kidney Disease in Juvenile Atlantic Salmon (Salmo salar) in the Margaree River

1969 ◽  
Vol 26 (9) ◽  
pp. 2535-2537 ◽  
Author(s):  
J. H. C. Pippy
Keyword(s):  
Kidney Disease ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
River System ◽  
Juvenile Salmon ◽  
Wild Salmon ◽  
Atlantic Salmon Salmo Salar ◽  
Bacterial Kidney Disease ◽  
Juvenile Atlantic Salmon

Bacterial kidney disease was presumptively identified in each of 25 hatchery-reared juvenile salmon (Salmo salar) but in only 2 of 235 wild juveniles in the Margaree River system. Apparently spread of disease from the hatchery to wild salmon in the river is very gradual.

Degradation of DDT in Atlantic Salmon (Salmo salar)

1968 ◽  
Vol 25 (11) ◽  
pp. 2321-2326 ◽  
Author(s):  
G. L. Greer ◽  
U. Paim
Keyword(s):  
Atlantic Salmon ◽  
Thin Layer ◽  
Thin Layer Chromatography ◽  
Salmo Salar ◽  
Aqueous Suspensions ◽  
Atlantic Salmon Salmo Salar ◽  
Salmon Parr ◽  
Layer Chromatography ◽  
Atlantic Salmon Parr

As indicated by thin-layer chromatography, hatchery-reared Atlantic salmon parr degraded DDT, absorbed from aqueous suspensions, to DDE and TDE within 9 hr. DDT adsorbed on external surfaces of the salmon was not degraded.

Transferrin Polymorphism in Atlantic Salmon (Salmo salar)

1970 ◽  
Vol 27 (9) ◽  
pp. 1617-1625 ◽  
Author(s):  
Dag Møller
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Genetic Basis ◽  
Gene Frequencies ◽  
Wild Salmon ◽  
Atlantic Salmon Salmo Salar ◽  
Different Populations ◽  
Transferrin Polymorphism ◽  
Starch Agar

Three main patterns of transferrins, made up of two molecular types, were found by starch–agar electrophoresis in plasma of hatchery and wild Atlantic salmon (Salmo salar).Distributions of the observed patterns from progenies of three hatchery matings agreed with expected Mendelian distributions in offspring of known parentage, implying that the bands have their origin in two codominant alleles. In nearly all samples of the wild salmon the genetic basis of transferrin variation was demonstrated by nonsignificant differences between observed and expected distributions when the Hardy–Weinberg formula was applied.Frequencies of the TfA allele differed in samples from different rivers and within the same river; the Atlantic salmon forms genetically different populations. Interchange of stocks probably influenced the values of the different gene frequencies found.

Downstream Movements and Estuarine Residence by Atlantic Salmon Parr (Salmo salar)

1989 ◽  
Vol 46 (9) ◽  
pp. 1466-1471 ◽  
Author(s):  
R. A. Cunjak ◽  
E. M. P. Chadwick ◽  
M. Shears
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Significant Proportion ◽  
River Mouth ◽  
Northwest Coast ◽  
Total Production ◽  
Younger Age ◽  
Mean Size ◽  
Salmon Parr ◽  
Atlantic Salmon Parr

Downstream migrations and estuarine residence by Atlantic salmon (Salmo salar) parr and smolts were studied in a small river on the northwest coast of Newfoundland in 1983 and in 1987. There were large downstream migrations in the spring and small downstream migrations in the fall. The major differences between the two types of migrant were that parr migrated about 1 wk before smolts and at a younger age compared with smolts and while parr remained in the estuary throughout the summer, smoits did not. Modal age and mean size were less for parr sampled in the estuary compared with those sampled at the counting-fence which suggested that the smallest parr were not captured by the fence. The estuarine population of parr represented a significant proportion of the river's total production of salmon. Parr were found throughout the estuary in salinities up to 24 parts per thousand but were most abundant near the river mouth. There was evidence that larger parr became smolts and eventually migrated to sea, but smaller parr probably returned to the river for overwintering. It is clear that estuaries should be included as habitat used for rearing Atlantic salmon.

Patterns in apparent survival of Atlantic salmon (Salmo salar) parr in relation to variable ice conditions throughout winter

2010 ◽  
Vol 67 (11) ◽  
pp. 1744-1754 ◽  
Author(s):  
Tommi Linnansaari ◽  
Richard A. Cunjak
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Anthropogenic Impacts ◽  
River Regulation ◽  
Ice Formation ◽  
Winter Period ◽  
Winter Mortality ◽  
Apparent Survival ◽  
Atlantic Salmon Salmo Salar ◽  
Salmon Parr

Apparent within-site survival of Atlantic salmon ( Salmo salar ) parr, individually tagged with passive integrated transponders, was not constant throughout the winter period in a 3-year study (2003–2006) in Catamaran Brook, New Brunswick, Canada. Highest decline in apparent survival (19.4%–33.3% of the study population) occurred prior to any ice formation and coincided with early winter acclimatization period (dynamic temperature and discharge regime). Stream discharge and parr maturity were identified to be relevant factors explaining emigration prior to ice formation. Apparent survival was improved during the period affected by subsurface ice and considerably better when surface ice was prevailing, with a decline in population size between 0% and 15.4%. Overall, observed within-site winter mortality was low (4.4%), and the majority of the loss of tagged salmon parr occurred because of emigration. On average, the within-site population of tagged salmon parr declined by 31.7% over the whole winter (November–April). Our data suggest that anthropogenic impacts, like climate change or river regulation, are likely to affect the apparent survival rate and distribution of juvenile Atlantic salmon because of their effects on natural ice regime in streams.

Performance of farmed, hybrid, and wild Atlantic salmon (Salmo salar) families in a natural river environment

2012 ◽  
Vol 69 (12) ◽  
pp. 1994-2006 ◽  
Author(s):  
Øystein Skaala ◽  
Kevin A. Glover ◽  
Bjørn T. Barlaup ◽  
Terje Svåsand ◽  
Francois Besnier ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Growth Rates ◽  
Egg Size ◽  
Relative Survival ◽  
Hybrid Progeny ◽  
Wild Salmon ◽  
Farmed Salmon ◽  
Atlantic Salmon Salmo Salar ◽  
Sib Families

Survival, growth, and diet were compared for farmed, hybrid, and wild Atlantic salmon (Salmo salar) families from the eyed egg to the smolt stage in River Guddalselva, Hardangerfjord, Norway. All individuals that survived until the smolt stage were captured in a Wolf trap and identified to one of the 69 experimental families using microsatellite markers. Survival of farmed salmon progeny was significantly lower than that of hybrids and wild progeny. However, survival varied considerably, from 0.17% to 6.4%, among farmed families. Egg size had an important influence on survival. Half-sib hybrid families with a farmed mother had higher survival when fathered by wild salmon than by farmed salmon. The overall relative survival of farmed families compared with that of their hybrid half-sib families fell from 0.86 in the second cohort to 0.62 in the last cohort with increasing fish density. Smolts of farmed parents showed significantly higher growth rates than wild and hybrid smolts. The overlap in diet among types of crosses demonstrates competition, and farm and hybrid progeny therefore will reduce the river’s capacity for production of wild salmon.

scholarly journals Size of wild and hatchery-reared Atlantic salmon populations in the northern Baltic Sea estimated by a stratified mark-recapture method

2006 ◽  
Vol 63 (8) ◽  
pp. 1477-1487 ◽  
Author(s):  
Antti Siira ◽  
Petri Suuronen ◽  
Petri Kreivi ◽  
Jaakko Erkinaro
Keyword(s):  
Atlantic Salmon ◽  
Baltic Sea ◽  
Salmo Salar ◽  
Total Size ◽  
Mark Recapture ◽  
Wild Salmon ◽  
Gulf Of Bothnia ◽  
River Mouths ◽  
Salmon Smolt ◽  
Feeding Migration

Abstract We estimated the total size of the Atlantic salmon (Salmo salar) population complex (wild and cultured) in the Gulf of Bothnia, northern Baltic Sea, using a stratified mark-recapture method. In 2001 and 2002, 1970 salmon were captured by the commercial trapnet fishery and tagged with external arrow tags. A total of 349 tagged fish was later recaptured among 65 180 salmon screened for tags. Recoveries were gathered by the commercial trapnets and by screening fish entering counting facilities in rivers and broodstock fisheries at the river mouths. In addition, tags were recovered from recreational river catches. Our estimates suggest that the total size of the migrating population in both years was about 230 000 fish. Proportions of wild and cultured salmon differed between the two years. In 2001, the proportion of wild salmon was 37%; the corresponding figure for 2002 was 62%. Based on estimates of wild salmon smolt production and the number of released smolts, the estimated proportion of cultured smolts that survived the feeding migration and returned to the Gulf of Bothnia (2–4%) was approximately 2.5–4.5 times lower than that of wild smolts (9–10%).

Assessing the impacts of acidification on Atlantic salmon (Salmo salar): a simple model of stream chemistry

1998 ◽  
Vol 55 (9) ◽  
pp. 2117-2126 ◽  
Author(s):  
D R Marmorek ◽  
G L Lacroix ◽  
J Korman ◽  
I Parnell ◽  
W D Watt
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Acid Neutralizing Capacity ◽  
Chemical Model ◽  
Charge Balance ◽  
Charge Densities ◽  
Atlantic Salmon Salmo Salar ◽  
F Factor ◽  
Neutralizing Capacity ◽  
Salmon Smolt

We developed a model that simulates the effects of changes in sulphate (SO42-) deposition on the chemistry of naturally organic-rich streams, linked this chemical model to a model of Atlantic salmon (Salmo salar) production (Korman et al. 1994. Can. J. Fish. Aquat. Sci. 51: 662-680), and assessed its performance on three acidified streams in southwest Nova Scotia. The chemical model closely tracked current chemistry by estimating the charge density required for charge balance on each sampling date. Calculated charge densities were generally low (1-3 µequiv./mg dissolved organic carbon (DOC)), inversely related to DOC, and positively related to pH. Predictions of minimum pH and salmon smolt output were relatively insensitive to the assumed F-factor (watershed neutralization of deposited acidity) in the parameter range most likely for the three streams. The model permits rapid impact assessment of acid deposition scenarios with a modest amount of input data (acid-neutralizing capacity, pH, SO42-, and DOC, ideally sampled weekly) while retaining natural cycles and processes.

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