scholarly journals Hyper- and Hypo-Osmoregulatory Performance of Atlantic Salmon (Salmo salar) Smolts Infected With Pomphorhynchus tereticollis (Acanthocephala)

2021 ◽  
Vol 9 ◽  
Author(s):  
Ross W. Finlay ◽  
Russell Poole ◽  
Ger Rogan ◽  
Eileen Dillane ◽  
Deirdre Cotter ◽  
...  
Keyword(s):  
Blood Glucose ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Coastal Waters ◽  
Natural Infection ◽  
Infection Prevalence ◽  
Glucose Content ◽  
Plasma Chloride ◽  
Osmoregulatory Function ◽  
Chloride Concentrations

Migratory species must cope with different parasite communities in different environments, but little is known about the ecophysiological effects of parasites on migratory performance. Some species/strains of acanthocephalan parasites in the genus Pomphorhynchus use anadromous salmonids as preferred definitive hosts, perforating the intestines, destroying mucosa and inducing inflammation–all of which might affect osmoregulatory function during transition between freshwater and marine environments. We used genetic barcoding to identify acanthocephalans in the intestines of wild Irish Atlantic salmon (Salmo salar L.) smolts as being the recently taxonomically resurrected species Pomphorhynchus tereticollis. We then investigated whether natural infection intensities of this parasite were associated with reduced osmoregulatory performance, as measured by plasma chloride concentrations, or potentially elevated stress, as measured by blood glucose, of hosts in freshwater or saltwater environments (24 or 72 h in ∼26PPT salt water, reflecting salinities of coastal waters through which smolts migrate). Although infection prevalence was high amongst sampled smolts, no associations were found within or across treatment groups between parasite abundance and plasma chloride concentrations or blood glucose levels. We found no intestinal perforations that would indicate P. tereticollis had recently vacated the intestines of smolts in either of the saltwater groups. Exploratory sampling in the 2 years preceding the experiment indicated that parasite prevalence and abundance are consistently high and comparable to the experimental individuals. Collectively, these results indicate that naturally occurring abundances of P. tereticollis do not reduce osmoregulatory function or affect blood glucose content in fresh water or within 72 h of entering coastal waters, although delayed pathologies affecting marine survival may occur. Future consideration of ecophysiological interactions between anadromous fish hosts and their parasites across different osmotic environments should provide general insights into coevolution between migratory hosts and their parasites.

scholarly journals Natural infection of Atlantic salmon (Salmo salar L.) with salmonid alphavirus 3 generates numerous viral deletion mutants

2013 ◽  
Vol 94 (9) ◽  
pp. 1945-1954 ◽  
Author(s):  
Elin Petterson ◽  
Marit Stormoen ◽  
Øystein Evensen ◽  
Aase B. Mikalsen ◽  
Øyvind Haugland
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Natural Infection ◽  
Sequence Divergence ◽  
Heart Tissue ◽  
Full Length ◽  
Deletion Mutants ◽  
Genome Sequences ◽  
Pancreas Disease ◽  
Full Length Genome

Salmon pancreas disease virus (SPDV) also referred to as salmonid alphavirus (SAV) is a virus causing pancreas disease in Atlantic salmon (Salmo salar L.) and rainbow trout (Oncorhynchus mykiss). Although the virus causes an economically important disease, relatively few full-length genome sequences of SAV strains are currently available. Here, we report full-length genome sequences of nine SAV3 strains from sites farming Atlantic salmon geographically spread along the Norwegian coastline. The virus genomes were sequenced directly from infected heart tissue, to avoid culture selection bias. Sequence analysis confirmed a high level of sequence identity within SAV3 strains, with a mean nucleotide diversity of 0.11 %. Sequence divergence was highest in 6K and E2, while lowest in the capsid protein and the non-structural proteins (nsP4 and nsP2). This study reports for the first time that numerous defective viruses containing genome deletions are generated during natural infection with SAV. Deletions occurred in all virus strains and were not distributed randomly throughout the genome but instead tended to aggregate in certain areas. We suggest imprecise homologous recombination as an explanation for generation of defective viruses with genome deletions. The presence of such viruses, provides a possible explanation for the difficulties in isolating SAV in cell culture. Primary virus isolation was successfully achieved for only two of eight strains, despite extensive attempts using three different cell lines. Both SAV isolates were easily propagated further and concomitant viral deletion mutants present in clinically infected heart tissue were maintained following serial passage in CHH-1 cells.

Cortisol dynamics during seawater adaptation of Atlantic salmon Salmo salar

1985 ◽  
Vol 248 (6) ◽  
pp. R651-R659 ◽  
Author(s):  
D. J. Nichols ◽  
M. Weisbart
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Plasma Protein ◽  
Protein Concentration ◽  
Extracellular Volume ◽  
Metabolic Clearance ◽  
Seawater Adaptation ◽  
Cortisol Metabolism ◽  
Atlantic Salmon Salmo Salar ◽  
Plasma Chloride

We examined plasma cortisol concentration (PCC), cortisol metabolism, and cortisol protein binding (CPB) in chronically cannulated Atlantic salmon (Salmo salar) during seawater (SW) adaptation. PCC rose significantly 2 h after freshwater (FW) to SW changeover but tended to be lower for 6 days thereafter. Plasma chloride concentrations began to stabilize 24–48 h after entry to SW. Cortisol metabolic clearance rate (MCR) was significantly higher 24 h after SW transfer than in FW; CPB and plasma protein concentration were significantly lower, but cortisol production rate was unchanged. The change in plasma chloride after 24 h in SW was negatively correlated with the change in plasma protein (r = -0.915, n = 9, P less than 0.001). The changes in CPB and plasma protein were correlated with the change in MCR (r = -0.643, n = 14, P less than 0.02; r = -0.850, n = 9, P less than 0.005). We hypothesize that these changes in protein concentration reflect an ion-induced expansion of extracellular volume and lead to increased MCR.

Responses of Juvenile Atlantic Salmon (Salmo salar) to Episodic Increases in Acidity of Nova Scotia Rivers

1987 ◽  
Vol 44 (8) ◽  
pp. 1475-1484 ◽  
Author(s):  
Gilles L. Lacroix ◽  
Donald R. Townsend
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Plasma Sodium ◽  
Ph Change ◽  
Atlantic Salmon Salmo Salar ◽  
Cough Response ◽  
Dissolved Aluminum ◽  
Electrolyte Loss ◽  
Decreasing Ph ◽  
Chloride Concentrations

Toxicity of different pH levels to Atlantic salmon (Salmo salar) parr held in floating pens for 54 d was assessed in four acidic streams of Atlantic Canada during the autumnal episode of increasing acidity. All parr died in the two streams where pH levels decreased below pH 4.7. Mortality was related to the rate of pH change and to parr size. Plasma sodium and chloride concentrations decreased by about 50–70 mmol∙L−1in parr of these two streams, and the rate of electrolyte loss was related to the rate and severity of pH change. In the other two streams, pH levels were never lower than pH 4.8 and no fish died. Plasma sodium and chloride concentrations in these parr decreased by 20–30 mmol∙L−1, but only after 30 d of exposure. Increased hematocrit, increased respiratory–cough response, and decreased feeding response, especially for parr in the most acidic streams, were also the result of stress apparently related to decreasing pH levels. Concentrations of labile aluminum were usually less than 10% of total dissolved aluminum and always less than 50 μg∙L−1in the four streams. Accumulation of aluminum in the gills of parr was not a significant factor in the lethal effects observed, which were more likely due to low pH.

The migratory behaviour of wild Atlantic salmon (Salmo salar) smolts in the estuary of the River Conwy, North Wales

1995 ◽  
Vol 52 (9) ◽  
pp. 1923-1935 ◽  
Author(s):  
A. Moore ◽  
E. C. E. Potter ◽  
N. J. Milner ◽  
S. Bamber
Keyword(s):  
Atlantic Salmon ◽  
Water Column ◽  
Fresh Water ◽  
Seasonal Change ◽  
Salmo Salar ◽  
Coastal Waters ◽  
Salt Water ◽  
Migratory Behaviour ◽  
Atlantic Salmon Salmo Salar ◽  
North Wales

Thirty-two wild Atlantic salmon (Salmo salar) smolts, tagged with miniature acoustic transmitters, were tracked in the River Conwy, North Wales, to describe the freshwater and estuarine patterns of migration. Migration in fresh water was predominantly nocturnal, although there was a seasonal change in this pattern with later run fish moving during both the day and night. Smolts tagged earlier in the study spent significantly longer in the river (mean 456 ± 43 h) before migrating into coastal waters than fish tagged later in the study (mean 201 ± 30 h). The movement of smolts through the estuary was indicative of a nocturnal selective ebb tide transport pattern of migration. All of the smolts migrated seawards on an ebb tide close to the surface and within the fastest moving section of the water column. The nocturnal pattern of migration would appear to be the result of an endogenous rhythm of swimming activity that results in the smolts moving up into the water column after dusk and migrating seawards. Smolt migration in the lower portion of the estuary was indicative of active directed swimming and there was no apparent period of acclimation required when moving from fresh to salt water.

Impacts of episodic acidification on in-stream survival and physiological impairment of Atlantic salmon (Salmo salar) smolts

2009 ◽  
Vol 66 (3) ◽  
pp. 394-403 ◽  
Author(s):  
Stephen D. McCormick ◽  
Amanda Keyes ◽  
Keith H. Nislow ◽  
Michelle Y. Monette
Keyword(s):  
Atlantic Salmon ◽  
New England ◽  
Salmo Salar ◽  
Ion Homeostasis ◽  
High Water ◽  
Connecticut River ◽  
Episodic Acidification ◽  
Atlantic Salmon Salmo Salar ◽  
Wide Range ◽  
Plasma Chloride

We conducted field studies to determine the levels of acid and aluminum (Al) that affect survival, smolt development, ion homeostasis, and stress in Atlantic salmon ( Salmo salar ) smolts in restoration streams of the Connecticut River in southern Vermont, USA. Fish were held in cages in five streams encompassing a wide range of acid and Al levels for two 6-day intervals during the peak of smolt development in late April and early May. Physiological parameters were unchanged from initial sampling at the hatchery and the high water quality reference site (pH > 7.0, inorganic Al < 12 μg·L–1). Mortality, substantial loss of plasma chloride, and gill Na+/K+-ATPase activity, and elevated gill Al occurred at sites with the lowest pH (5.4–5.6) and highest inorganic Al (50–80 μg·L–1). Moderate loss of plasma chloride, increased plasma cortisol and glucose, and moderately elevated gill Al occurred at less severely impacted sites. Gill Al was a better predictor of integrated physiological impacts than water chemistry alone. The results indicate that Al and low pH under field conditions in some New England streams can cause mortality and impair smolt development in juvenile Atlantic salmon and provide direct evidence that episodic acidification is impacting conservation and recovery of Atlantic salmon in the northeastern USA.

scholarly journals Escape history and proportion of farmed Atlantic salmon Salmo salar on the coast and in an adjacent salmon fjord in Norway

2020 ◽  
Vol 12 ◽  
pp. 371-383
Author(s):  
T Aronsen ◽  
EM Ulvan ◽  
TF Næsje ◽  
P Fiske
Keyword(s):  
Atlantic Salmon ◽  
Body Length ◽  
Salmo Salar ◽  
Coastal Waters ◽  
Wild Salmon ◽  
Farmed Salmon ◽  
Significant Difference ◽  
In The Wild ◽  
The Mean ◽  
Farmed Atlantic Salmon

To gain more knowledge about escaped farmed salmon Salmo salar in the wild, we investigated the proportion of escapees, body length at escape, proportion escaped as smolts/post-smolts (≤300 mm) and number of winters in the wild (winter zones in the growth pattern in the scale samples) in catches on the Norwegian coast and in an adjacent fjord from 2013 to 2017. The mean proportion of escapees was higher on the coast (26%) than in the fjord (4%), and escapees caught on the coast had a slightly larger mean body length at escape (607 mm) than in the fjord (557 mm). However, the mean proportion escaped as smolts/post-smolts did not differ significantly between the coast (8%) and the fjord (11%). There was also no significant difference in the mean proportion of farmed salmon with 1 or more winter zones after escape (50% on the coast and 56% in the fjord). The proportions of escapees with 1, 2, 3 or 4 winter zones after escape were 28, 20, 2 and 0.4% in catches on the coast and 30, 21 and 4% in catches in the fjord, respectively. This study found that the proportion of escapees was considerably higher in coastal waters than in the fjord. Escapees consisted of farmed salmon from several escape events over several years, and approximately 50% of the escapees had one or more winter zones after escape. Thus, escaped farmed salmon may pose a threat to wild salmon populations for several years after the escape event.

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