Effects of Pseudobranchectomy on Visual Pigment Density and Ocular PO2 in Atlantic Salmon, Salmo salar

1977 ◽  
Vol 34 (11) ◽  
pp. 2176-2184 ◽  
Author(s):  
C. M. Ballintijn ◽  
D. D. Beatty ◽  
R. L. Saunders
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Visual Pigment ◽  
Marked Decrease ◽  
Control Fish ◽  
Atlantic Salmon Salmo Salar ◽  
Initial Decrease ◽  
Contralateral Eye ◽  
The Right ◽  
Ophthalmic Arteries

Bilateral pseudobranchectomy (B.P.) of Atlantic salmon, Salmo salar, resulted in a progressive loss of visual pigment and a marked decrease in ocular PO2 near the retina. B.P. fish were dark and blind within a few hours of pseudobranchectomy. Unilateral pseudobranchectomy (U.P.) did not have a similar effect on ocular PO2 or visual pigment density in either the ipsilateral or the contralateral eye. U.P. fish did not become dark or blind. An interconnection exists between the right and left ophthalmic arteries permitting an intact pseudobranch to supply blood to the contralateral eye whose pseudobranch has been removed. Although intramuscular injection of acetazolamide caused an initial decrease in amount of visual pigment, body darkening, and blindness, these effects were not permanent. Acetazolamide also caused a marked decrease in ocular PO2 similar to that in B.P. fish. In control fish, dorsal aortic blood and ocular PO2 values were dependent upon an adequate irrigation of the gills. Key words: salmonid, Salmo, pseudobranch, oxygen tension, eye, visual pigment

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.

Effects of Diet or Liming on Steroid Hormone Metabolism and Reproduction in Atlantic Salmon (Salmo salar) Held in an Acidic River

1990 ◽  
Vol 47 (12) ◽  
pp. 2422-2430 ◽  
Author(s):  
G. B. Sangalang ◽  
H. C. Freeman ◽  
J. F. Uthe ◽  
L. S. Sperry
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Reproductive Performance ◽  
Steroid Hormone ◽  
Control Fish ◽  
Dietary Salt ◽  
Hormone Metabolism ◽  
Atlantic Salmon Salmo Salar ◽  
Water Ph ◽  
Acidic River

Attempts to avert the impacts of an acidic river environment on Atlantic salmon (Salmo salar) were carried out in 1985 and 1986. Salmon were held in the Westfield River (pH 4.7–5.2) and the nearby Medway River (pH 5.3–5.6) during their sexual maturation. A diet containing 3% NaCl was fed to the Westfield salmon in 1985. Marble chips were used to elevate the pH of Westfield River water in 1986. Fish fed the salt diet had higher peak levels of plasma sex hormones, higher fecundity, greater incidence of spawners, lower egg mortality, and less weight loss than fish fed a commercial trout diet. The reproductive performance of fish held in limed water (pH 5.1–5.9) almost attained the level observed in the Medway (control) fish. Limestone treatment stimulated early peaking of blood androgen levels, testosterone, and 11-ketotestosterone in Westfield males, and 17α, 20β-dihydroxy-4-pregnen-3-one, a follicular mediator of gonadotropin, in a few Westfield females. The head kidneys produced more cortisol and corticosterone in all Westfield fish in both years compared to Medway fish. The results suggest that neither dietary salt nor liming completely prevented the decline of reproductive performance and the alteration of steroid hormone metabolism in salmon.

Effects of Thyroid Hormones on Behavior of Yearling Atlantic Salmon (Salmo salar)

1974 ◽  
Vol 31 (11) ◽  
pp. 1787-1790 ◽  
Author(s):  
J.-G. Godin ◽  
P. A. Dill ◽  
D. E. Drury
Keyword(s):  
Atlantic Salmon ◽  
Thyroid Hormones ◽  
Aggressive Behavior ◽  
Salmo Salar ◽  
Swimming Activity ◽  
Control Fish ◽  
Atlantic Salmon Salmo Salar

Swimming activity, aggressive behavior, and upstream orientation of yearling Atlantic salmon (Salmo salar) treated with 6.43 × 10−11 M thyroxine were significantly lower than those of control fish injected with solvent alone. Two concentrations of triiodothyronine (7.43 × 10−11 M; 7.43 × 10−10 M) caused similar but less pronounced effects.Because similar behavioral modifications accompany smolt migration, we hypothesize that thyroid hormones may play a role in arousing migratory tendencies in Atlantic salmon.

Evidence for Antifreeze Protein Gene Transfer in Atlantic Salmon (Salmo salar)

1988 ◽  
Vol 45 (2) ◽  
pp. 352-357 ◽  
Author(s):  
Garth L. Fletcher ◽  
Margaret A. Shears ◽  
Madonna J. King ◽  
Peter L. Davies ◽  
Choy L. Hew
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Cold Water ◽  
Restriction Enzymes ◽  
Antifreeze Protein ◽  
Winter Flounder ◽  
Control Fish ◽  
Pseudopleuronectes Americanus ◽  
Atlantic Salmon Salmo Salar ◽  
Antifreeze Polypeptides

Atlantic salmon (Salmo salar) freeze to death if they come into contact with ice at water temperatures below −0.7 °C. Consequently, sea-pen culture of this species in cold water is severely limited. Winter flounder (Pseudopleuronectes americanus) survive in ice-laden seawater by producing a set of antifreeze polypeptides (AFP). We are attempting to make the Atlantic salmon more freeze resistant by transferring antifreeze protein genes from the winter flounder to the genome of the salmon. Salmon eggs were microinjected with linearized DNA after fertilization. Individual fingerlings (1–2 g) were analyzed for flounder AFP genes by genomic Southern blotting. DNA from 2 out of 30 fingerlings showed hybridization to the flounder DNA probe. Hybridization bands following cleavage by restriction enzymes Sst l and Bam HI were identical to those of the injected DNA. Hybridization following Hind III digestion indicated that the flounder AFP gene was linked to the salmon genome. These hybridization signals were absent in the DNA from control fish. The intensity of the hybridization signals indicated that there was on average at least one copy of the AFP gene present per cell.

Role of Olfaction in the Behavioral and Neuronal Responses of Atlantic Salmon, Salmo salar, to Hydrographic Stratification

1985 ◽  
Vol 42 (10) ◽  
pp. 1658-1667 ◽  
Author(s):  
Kjell B. Døving ◽  
Håkan Westerberg ◽  
Peter B. Johnsen
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Water Samples ◽  
Olfactory Nerve ◽  
Control Fish ◽  
Fine Scale ◽  
Vertical Movements ◽  
Atlantic Salmon Salmo Salar ◽  
Hydrographic Features ◽  
Ultrasonic Tracking

The behavior of sham-operated and anosmic Atlantic salmon, Salmo salar, was studied in a fjord system with close reference to the fine-scale hydrographic features. Control fish made small-amplitude vertical movements, with sudden large-amplitude excursions. The anosmic fish made large continuous searches up and down in the water column, descended below the sill depth of the fjord, and followed the bottom contours. None of these three behaviors was seen in the control fish. The trauma caused by the surgical incision did not prevent the fish from active swimming, and a fish with unilateral sectioning of the olfactory nerve returned to the river of release. Activity of single olfactory bulb neurons was recorded during stimulation of salmon olfactory epithelium with water samples taken from different depths of the fjord. These water samples had been taken from regions that showed layering and to which migrating salmon demonstrated behavioral preferences in ultrasonic tracking experiments. Ninety percent of responding neurons showed differencial responses to the water samples, indicating the capacity of the olfactory system to discriminate among stratified water layers found in the ocean. We conclude that olfactory discrimination of fine-scale hydrographic features may provide a necessary reference system for successful orientation in nearshore regions by salmon.

Buoyancy Compensation by Atlantic Salmon (Salmo salar) Smolts Tagged Internally with Dummy Telemetry Transmitters

1976 ◽  
Vol 33 (6) ◽  
pp. 1377-1380 ◽  
Author(s):  
Stephen M. Fried ◽  
James D. McCleave ◽  
Kristin A. Stred
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Recovery Time ◽  
Water Surface ◽  
Control Fish ◽  
Partial Recovery ◽  
Atlantic Salmon Salmo Salar ◽  
Percent Recovery ◽  
Negative Buoyancy ◽  
Over Time

Negative buoyancy was induced in Atlantic salmon (Salmo salar) smolts by insertion of dummy telemetry tags (4.0 g in water) into the stomach. Buoyancy adjustment by means of swimbladder volume change was determined in tagged and untagged (control) smolts either allowed or denied access to the water surface. Regression of percent recovery of initial buoyancy on recovery time showed that tagged fish with access to the surface gradually increased their buoyancy over a 6-h test period. Only 1 of 28 fish held 0.5–2.0 h recovered its initial buoyancy, while 7 of 26 held 2.5–4.0 h recovered, and 7 of 24 held 4.5–6.0 h recovered. Tagged fish without access to the surface never regained buoyancy and became slightly heavier with time. Two tagged fish without access to air were unable to compensate for negative buoyancy after 24 h, but exhibited total or partial recovery when examined 6 h after being allowed access. Control fish did not alter buoyancy with handling or over time.

HEPATOGENESIS OF THE ATLANTIC SALMON (SALMO SALAR L.)

1942 ◽  
Vol 20d (4) ◽  
pp. 79-97 ◽  
Author(s):  
Helen I. Battle
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Ventral Surface ◽  
Intestinal Loop ◽  
Clockwise Rotation ◽  
Atlantic Salmon Salmo Salar ◽  
Ductus Choledochus ◽  
Yolk Absorption ◽  
Pyloric Stomach ◽  
The Right

The anlage of the liver of the Atlantic salmon, Salmo salar L., arises during the eleventh week, 4.0 mm. embryo, as a proliferation of entodermal cells from the ventral wall of the anterior intestinal region. This anlage soon takes on a double appearance caudally. In embryos of 12 to [Formula: see text] weeks (4.7 to 5.0 mm.) it consists of right and left primordia with a common ventral opening into the intestine. By 13 weeks (5.4 mm. embryo) the anlage has curved toward the left, a position assumed through the counter-clockwise rotation of the intestine. The cells are becoming arranged in cords. A subsequent clockwise rotation of the intestine, apparent first in embryos of 14 weeks (6.5 mm.), draws the anlage to a dextroventral position. By 16 weeks (8.5 mm.) the ductus choledochus enters the right side of the intestine; the anlage itself passes posteriorly along the ventral surface of the intestine then abruptly forward in the form of a hook to the right of the intestine. The liver cells are arranged as branching trabeculae with some indication of vascularization. The liver anlage becomes rhomboidal and migrates to a position on the right of the rectilinear intestine, where it remains until some time after hatching. In the 25 mm. alevin (26 days after hatching) the intestine through a process of flexion commences to differentiate into cardiac and pyloric stomach, ascending and descending limbs of intestine. Simultaneously the papilla duodeni marking the opening of the ductus choledochus into the intestine is carried to a sinistrodorsal position opening into the ascending limb of the intestine at the level of the second row of pyloric caeca. Subsequent clockwise rotation of the ascending limb finally carries it to the sinistroventral margin. Yolk absorption now permits the liver to grow ventrad to the intestine, while the anterior progression of the intestinal loop is instrumental in its migration to the anterior end of the coelom. In the early parr the liver is somewhat triangular in shape with the apex posterior and in the mid-line. Through unequal growth the left median lobe in the late parr becomes much longer than the right, from which, however, it is never distinctly divided. It has now assumed the general appearance of the organ in the smolt and adult. Enlargement of the blind end of the ductus choledochus in the 21 week embryo (11.8 mm.) forms the gall bladder. Hepatic ducts are formed as branches of the primary ductus choledochus.

Evidence for sea lice-induced marine mortality of Atlantic salmon (Salmo salar) in western Ireland from experimental releases of ranched smolts treated with emamectin benzoate

2012 ◽  
Vol 69 (2) ◽  
pp. 343-353 ◽  
Author(s):  
P.G. Gargan ◽  
G. Forde ◽  
N. Hazon ◽  
D.J.F. Russell ◽  
C.D. Todd
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Salmo Trutta ◽  
Conservation Status ◽  
Sea Lice ◽  
Control Fish ◽  
Emamectin Benzoate ◽  
Sea Trout ◽  
Atlantic Salmon Salmo Salar ◽  
Western Ireland

Sea trout ( Salmo trutta ) stock collapses in coastal areas of western Ireland subject to salmon aquaculture were contemporaneous with high abundances of larval sea lice ( Lepeophtheirus salmonis ) on juvenile sea trout. Whereas sea trout remain in near-shore waters throughout their marine migration, Atlantic salmon ( Salmo salar ) smolts typically move quickly offshore into oceanic waters. It might therefore be predicted that salmon smolts would be less vulnerable to coastal stressors and less likely to be negatively affected by infestations of sea lice early in their marine phase. Groups of microtagged, hatchery-reared Atlantic salmon smolts were fed either untreated pellets or pellets incorporating the in-feed sea louse treatment SLICE (emamectin benzoate) prior to eight experimental releases in three marine locations over a 3-year period. In total, 74 324 smolts were released and analysis of tag recaptures from returning adult salmon showed that emamectin-treated smolts experienced increased survivorship and were 1.8 times more likely to return compared with control fish. These results suggest that sea lice-induced mortality on adult Atlantic salmon returns in Ireland can be significant, and that sea lice larvae emanating from farmed salmon may influence individual survivorship and population conservation status of wild salmon in these river systems.

Correlation of Morphological and Intra-ocular Measurements in the Atlantic Salmon (Salmo salar) Yearling

1961 ◽  
Vol 18 (2) ◽  
pp. 259-272 ◽  
Author(s):  
M. A. Ali ◽  
P. Copes ◽  
W. R. Stevenson
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Higher Order ◽  
Atlantic Salmon Salmo Salar ◽  
The Right ◽  
Low Order

In the Atlantic salmon yearling, correlation among various morphological measurements is of a higher order than correlation of various intra-ocular measurements. While the latter correlation is positive, it is not of a high enough order to serve as a useful predictive device. Correlation between intra-ocular measurements from the left and the right eyes is also of a low order.

Changes in the Olfactory Function of Atlantic Salmon, Salmo salar, in the Course of Smoltification

1992 ◽  
Vol 49 (8) ◽  
pp. 1704-1713 ◽  
Author(s):  
Pierre-Philippe Morin ◽  
Kjell B. Døving
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Response Threshold ◽  
Sensitive Period ◽  
Electrophysiological Response ◽  
Atlantic Salmon Salmo Salar ◽  
Odor Memory ◽  
Odor Learning ◽  
The Right ◽  
Two Peaks

Electrophysiological responses were recorded from the surface of the rostromedial and rostrolateral regions of the right olfactory bulb of Atlantic salmon, Salmo salar, during stimulation of the olfactory epithelium with different concentrations of L-alanine and taurocholate. Fish exposed to taurocholate prior to testing were compared with nonexposed fish. The results revealed significant week-to-week differences in olfactory activity in nonexposed fish, with two peaks in activity of similar magnitude. The first peak occurred at the beginning of smoltification, when olfactory sensitivity reached its maximum (low response threshold). The second peak occurred after smoltification, when sensitivity was roughly 10 times lower (higher response threshold) than during the first peak. Fish exposed to taurocholate prior to testing did not exhibit these peaks in olfactory activity. Marked changes in the spatial distribution of the electrophysiological response to L-alanine and taurocholate occurred throughout the smoltification process in nonexposed fish. The two peaks in olfactory activity that we identified coincide with two peaks in odor learning (Morin et al. 1989. Can. J. Fish. Aquat. Sci. 46: 122–130, 131–136); the first coincides with a unique capacity for odor memory and is apparently a neural manifestation of a sensitive period for olfactory imprinting in Atlantic salmon.

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