Variable Seaward Migration of Salmon

1945 ◽  
Vol 6d (4) ◽  
pp. 311-325 ◽  
Author(s):  
A. G. Huntsman
Keyword(s):  
Salmo Salar ◽  
River Discharge ◽  
Wide Distribution ◽  
Shallow Estuary ◽  
Seaward Migration

Salmon (Salmo salar) kelts from hatchery operations, when liberated in rivers and in or near river estuaries, show by the distribution of the recaptured fish an extent of seaward migration that varies from river to river, apparently in relation to the character of the estuary and river influence in the sea. For the very large St. John river (N.B.) they are mainly in the long, deepish estuary and rarely leave the zone of river influence, while for the smallish Margaree river (N.S.), with a short, shallow estuary well emptied by the tide, they are mainly near the coast outside the estuary and commonly wander to distant places in various directions. This distribution may (Margaree) or may not (St. John) correspond with that of virgin fish. The Miramichi (N.B.) with strong river influence and long estuary resembles the St. John, while the Annapolis and Philip rivers (N.S.) with slight river influence are more like the Margaree.For each river and location of liberation, the extent of seaward distribution is found to vary with differences in river discharge during a presumed settling-down period after liberation. Sharp freshets are correlated with more riverward distribution at least for a time. Heavy floods are correlated with a more seaward distribution. Continued low water is correlated with a wide distribution.

Evidence of Acidification of Some Nova Scotian Rivers and Its Impact on Atlantic Salmon, Salmo solar

1983 ◽  
Vol 40 (4) ◽  
pp. 462-473 ◽  
Author(s):  
W. D. Watt ◽  
C. D. Scott ◽  
W. J. White
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
River Discharge ◽  
Average Rate ◽  
Metamorphic Rocks ◽  
Ph Variation ◽  
The Past ◽  
Discharge Rates ◽  
Ph Range ◽  
Nova Scotian

River pH's in Nova Scotia are closely related to geology, and seasonal pH variation is well correlated with river discharge rates. In the geologically sensitive areas (granite and metamorphic rocks), river pH's have fallen significantly over the past 27 yr at an apparent average rate of 0.017 pH units/year. Concomitant with this decrease are a decline in [Formula: see text] concentrations and increases in Al+++ and [Formula: see text]. On average, 73% of the increase in acid is attributable to increased [Formula: see text]. Changes in Na+, K+, Ca++, and Mg++ concentrations were not significant. In rivers presently at mean annual pH's < 4.7, the Atlantic salmon (Salmo salar) runs have disappeared and are presumed extinct. Rivers in the pH range 4.7–5.0 show a decline in salmon angling returns of 2.8%/yr, beginning about 1954, and low densities of juvenile salmon. Rivers presently of pH > 5.0 generally have normal juvenile densities and show no significant trend in angling returns.

Imprinting and Homing of Atlantic Salmon (Salmo salar) Kelts

1989 ◽  
Vol 46 (4) ◽  
pp. 714-719 ◽  
Author(s):  
J. R. Foster ◽  
C. B. Schom
Keyword(s):  
Atlantic Salmon ◽  
New Brunswick ◽  
Salmo Salar ◽  
Release Site ◽  
Behavioral Changes ◽  
Salmon River ◽  
Delayed Release ◽  
Atlantic Salmon Salmo Salar ◽  
Seaward Migration ◽  
Passamaquoddy Bay

Experiments were conducted to determine if a process similar to imprinting occurs during each seaward migration of Atlantic Salmon (Salmo salar). Displaced Atlantic salmon kelts homed to the site from which they had previously emigrated to sea as smolts (Big Salmon River, New Brunswick, Canada) and did not home to their release sites, or their overwintering sites 150 km away. Delaying release of kelts past the time of normal seaward migration did not cause the behavioral changes associated with interference of the imprinting process described for smolts. Delayed release kelts did not remain near their seawater or estuarine release sites, home to their release sites, or non-selectively home to suitable spawning streams near their release sites. Delayed released kelts travelled away from the release site faster than kelts released during their normal time of seaward migration, but they did not return either to Passamaquoddy Bay or their natal stream in the calendar year of their release (the normal time for this stock) or in subsequent years.

Seawater Adaptability in Baltic Salmon (Salmo salar): A Bimodal Smoltification Pattern in Previously Mature Males

1992 ◽  
Vol 49 (6) ◽  
pp. 1097-1106 ◽  
Author(s):  
Ingemar Berglund ◽  
Monika Schmitz ◽  
Hans Lundqvist
Keyword(s):  
Body Size ◽  
Salmo Salar ◽  
Mature Male ◽  
The Other ◽  
Seaward Migration ◽  
Previous Autumn ◽  
Mature Male Parr ◽  
Immature Fish

In three years, maximum seawater adaptability in 2-yr-old Baltic salmon (Salmo salar) was found during a period of about 2 wk in late May – early June. At this time the previously mature males developed in one of two directions. One group (8–44%) developed a seawater adaptability comparable with that of immature fish whereas the other did not. Previously mature males that did not adapt to seawater had larger gonadosomatic indices than males with good performance in seawater. Individually tagged previously mature males and immature fish released into the river in spring had a total adult recapture rate of 1.6 and 11.6%, respectively. In both groups the recapture rate was highest for fish released about 2 wk before the time of optimal seawater adaptability. The effect of size on recapture rate was more pronounced among previously mature males than among immature fish, with a particularly low recapture rate of small previously mature males. It is suggested that previously mature male parr can either mature sexually again or complete smoltification in spring and that the probability for smoltification and seaward migration is affected by body size and the conditions for growth during the previous autumn–winter.

Advances in Fisheries Bioengineering

2008 ◽  
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
River Discharge ◽  
Fish Passage ◽  
Migratory Fish ◽  
Small Hydropower ◽  
Passive Integrated Transponder ◽  
Fish Size ◽  
Diversion Structure ◽  
Hydroelectric Plants

<em>Abstract</em>.—A 2-year experiment was conducted on the Ariège River (southwest France) to assess effectiveness of downstream fish passage facilities for Atlantic salmon <em>Salmo salar </em>smolts at four consecutive small hydroelectric plants located on a diversion structure. The efficiency of these bypasses, evaluated using passive integrated transponder (PIT) telemetry, varied significantly between sites. The highest efficiency (greater than 65%) was obtained with two entirely new downstream passage facilities, whereas less than 40% of PIT-tagged smolts migrated through two other bypasses that were simple retrofits of existing trash sluices. Performances of two bypasses were significantly improved using either a submerged horizontal screen designed to limit upwelling or mercury lights at the bypass entrance. At two sites, a difference in fish size was also observed between smolts using the bypasses and those passing through the conventional intake trash racks, with larger fish using the bypass and smaller fish being entrained through the turbine intake. It was also demonstrated that the probability for spillway passage by tagged fish increased with increases in the proportion of total river discharge spilling and with decreases in fish size. The results of this study demonstrate how different parameters can influence downstream bypass efficiencies and provide information on how downstream passage for migratory fish can be improved at small hydropower projects.

scholarly journals Basin-scale phenology and effects of climate variability on global timing of initial seaward migration of Atlantic salmon (Salmo salar)

2013 ◽  
Vol 20 (1) ◽  
pp. 61-75 ◽  
Author(s):  
Jaime Otero ◽  
Jan Henning L'Abée-Lund ◽  
Ted Castro-Santos ◽  
Kjell Leonardsson ◽  
Geir O. Storvik ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Climate Variability ◽  
Salmo Salar ◽  
Atlantic Salmon Salmo Salar ◽  
Basin Scale ◽  
Seaward Migration

Prediction of Angler Success in an Atlantic Salmon, Salmo salar, Fishery Two Fishing Seasons in Advance

1986 ◽  
Vol 43 (12) ◽  
pp. 2531-2534 ◽  
Author(s):  
Patrick M. Ryan
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Catch Per Unit Effort ◽  
Atlantic Salmon Salmo Salar ◽  
Unit Effort ◽  
Seaward Migration

The number of young Atlantic salmon, Salmo salar, in the spring in two lakes at the headwaters of the Gander River, Newfoundland, was positively correlated (r = 0.99) with the number of smolts in the subsequent seaward migration over a 5-yr period. Angler success (catch per unit effort) in the grilse fishery on the Gander River over a 7-yr period was positively correlated (r = 0.81) with the number of young in the lakes prior to the opening of the angling season of the previous year. Measures of the abundance of young salmon in freshwaters prior to the smolt run can be used to predict the size of the smolt run and allow for compensatory modifications to the adult fishery a year in advance of acticipated low adult returns.

Downstream migration in Atlantic salmon (Salmo salar) smolt sibling groups

2004 ◽  
Vol 61 (3) ◽  
pp. 328-331 ◽  
Author(s):  
K Håkan Olsén ◽  
Erik Petersson ◽  
Bjarne Ragnarsson ◽  
Hans Lundqvist ◽  
Torbjörn Järvi
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Kin Recognition ◽  
Juvenile Fish ◽  
Downstream Migration ◽  
Migratory Behaviour ◽  
Atlantic Salmon Salmo Salar ◽  
Seaward Migration ◽  
Structured Groups ◽  
Experimental Stream

Previous studies have shown kin recognition abilities in salmonid fish. Some authors have suggested that the attraction of juvenile fish to siblings may indicate preference for shoaling with kin. The aim of the present study is to test the prerequisite for the hypothesis that siblings swim spatially closer than unrelated fish during their seaward migration as smolts. Atlantic salmon (Salmo salar) eggs from three families were each reared in two tanks to create familiar and unfamiliar sibling smolts. Before the experiment started they were tagged individually withpassive integrated transponders (PITs). Twelve individuals from each of six groups were mixed and released together at several occasions in the upper end of the 400-m-long experimental stream. An automatic PIT-monitoring system placed in the outlet recorded the time for passage of each individual leaving the stream. Eighty-five percent of the juveniles monitored by the PIT antenna showed downstream migration at night hours and they migrated significantly more often closer in time to both known and unknown siblings than to unrelated fish. The results suggest that there is a genetic component in the migratory behaviour of Atlantic salmon smolts and support the hypothesis that smolts migrate in kin-structured groups.

Influence of Parr Maturity on Emigration of Smolting Atlantic Salmon (Salmo salar)

1989 ◽  
Vol 46 (3) ◽  
pp. 410-415 ◽  
Author(s):  
L P. Hansen ◽  
B. Jonsson ◽  
R. I. G. Morgan ◽  
J. E. Thorpe
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Sexual Maturity ◽  
Release Site ◽  
Atlantic Salmon Salmo Salar ◽  
Seaward Migration

Sexual maturity of parr reduces the probability of a future seaward migration. In release experiments in two separate years with Atlantic salmon in the Imsa River, Norway, immatures migrated sooner and in significantly higher proportions (P < 0.001) than did previously mature males. Furthermore, higher proportions of 2-yr olds than of 1-yr olds migrated, and 86–92% of the descent occurred at night. Large 2-yr olds migrated before smaller ones. Among those which did not migrate, some (3.2% of those released in 1986) were recaptured in the autumn, of which 91.9% were mature males. At Lussa, Scotland, 5.6 and 5.9% of smolting fish released in two separate years remained resident at the release site throughout the summer, and 91.8 and 93.4% of these matured in the autumn of the release year.

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