Dispersal of Atlantic salmon fry from a natural redd: evidence for undergravel movements?

1993 ◽  
Vol 71 (7) ◽  
pp. 1454-1457 ◽  
Author(s):  
Carlos Garcia de Leaniz ◽  
Neil Fraser ◽  
Felicity Huntingford
Keyword(s):  
Atlantic Salmon ◽  
Water Column ◽  
Salmo Salar ◽  
Seasonal Patterns ◽  
Salmon Fry

In this paper we describe a modified version of a box trap used for bank-to-bank trapping during a study of dispersal of Atlantic salmon fry (Salmo salar L.). Two such traps were positioned 2 m upstream and downstream of a single isolated natural redd and a third was placed 20 m downstream. All fry captured in each trap were marked and released beyond the trap. Of the fish caught in the second downstream trap, 64% were unmarked. The seasonal patterns of trapping for marked and unmarked fish were identical, but the unmarked fish were significantly smaller than their marked peers. We argue that these unmarked captures represent fish that evaded capture in the first downstream trap, either by dispersing from the redd deep within the gravel or by leaving the water column and burrowing into the gravel on encountering the trap. Implications for the interpretation of trapping data on newly emerged salmonids are discussed.

Annual variation in size-selective mortality of Atlantic salmon (Salmo salar) fry

2001 ◽  
Vol 58 (6) ◽  
pp. 1187-1195 ◽  
Author(s):  
S P Good ◽  
J J Dodson ◽  
M G Meekan ◽  
D AJ Ryan
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Total Mortality ◽  
Weather Conditions ◽  
Fish Length ◽  
Selective Mortality ◽  
Atlantic Salmon Salmo Salar ◽  
Salmon Fry ◽  
Mean Size ◽  
The Mean

We investigated the size-selective mortality of Atlantic salmon (Salmo salar) fry during two consecutive summers that differed markedly in weather conditions. We sampled fry shortly after emergence in June and at the end of August to compare the distributions of back-calculated body size at hatching by examining otolith microstructure. Size-selective mortality was observed in both summers; however, the direction and strength of mortality differed. During the drought conditions of 1995, selective mortality was relatively weak and directed towards the smaller fry in the population. During the flood conditions of 1996, selective mortality was relatively strong and directed towards the larger fry of the same population. Interannual variability in size-selective mortality contributed to significant differences in the mean size of fry at the end of their first summer of life. Size-selective mortality rates estimated from the shifts in fish length at hatching observed during the first summer of life were comparable with published estimates of total mortality of Atlantic salmon fry, indicating that early mortality may be largely size selective. Mortality associated with hydroclimatic events can select against either small or large fish and is a key determinant of mean size attained by the end of the first summer of life.

Emergence, population densities, and growth of salmon and trout fry in two New Brunswick streams

1982 ◽  
Vol 60 (10) ◽  
pp. 2239-2244 ◽  
Author(s):  
Robert G. Randall
Keyword(s):  
Atlantic Salmon ◽  
New Brunswick ◽  
Salmo Salar ◽  
Salvelinus Fontinalis ◽  
Early Growth ◽  
Population Densities ◽  
Salmon Fry ◽  
Dependent Growth ◽  
Growth Differences ◽  
Catch Rates

Postemergent downstream dispersal of Atlantic salmon fry (Salmo salar) was monitored using drift samplers during spring 1978 in two Miramichi River, N.B., tributaries. Catch rates of salmon fry peaked during the 2nd and 3rd weeks of June in both streams, coinciding with peak emergence of the salmon from the gravel. Very few trout fry (Salvelinus fontinalis) were captured in the drift nets, but electrofishing results indicated trout emergence preceded salmon by about 3 weeks.The earlier emergence of the trout gave them an early growth advantage over the salmon, so that trout fry were usually larger than salmon fry inhabiting the same stream areas. Early growth rates of both salmon and trout were quite varied among four stream sites during 2 years when growth was monitored; growth differences were discussed in relation to stream temperatures and density-dependent growth. Salmon fry were more abundant than trout fry at most sites in both years.

Selection of Microhabitat in Summer by Juvenile Atlantic Salmon (Salmo salar)

1987 ◽  
Vol 44 (1) ◽  
pp. 120-129 ◽  
Author(s):  
D. L. Morantz ◽  
R. K. Sweeney ◽  
C. S. Shirvell ◽  
D. A. Longard
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
The Body ◽  
Flow Conditions ◽  
Atlantic Salmon Salmo Salar ◽  
Juvenile Atlantic Salmon ◽  
Salmon Fry ◽  
Study Sites ◽  
Selection Of ◽  
Atlantic Salmon Parr

This study was designed to define the microhabitats selected in summer by juvenile Atlantic salmon (Salmo salar). Curves were developed describing the preference of 880 young salmon for water velocity at the fish's position (nose velocity), mean water column velocity, total water depth, and stream substrate size. Study sites were chosen in six morphologically diverse streams in Nova Scotia and New Brunswick during 1982–84. Of the four variables measured, only nose velocity chosen by both fry and parr was not significantly different among years or rivers. Atlantic salmon fry (< 65 mm) most frequently selected nose velocities between 5 and 15 cm∙s−1, small parr (65–100 mm) between 5 and 25 cm∙s−1 and large parr (> 100 mm) between 5 and 35 cm∙s−1. Apparently, juvenile salmon utilized water depths and stream substrates which varied within tolerable limits according to their availability in conjunction with preferred water velocities. Significant differences in the body shape and size of the pectoral fin of Atlantic salmon parr in different rivers did not influence the selection of nose velocities within the range of flow conditions sampled.

Daily and seasonal patterns in the feeding behaviour of Atlantic salmon (Salmo salar L.) in a sea cage

Aquaculture ◽  
1993 ◽  
Vol 117 (1-2) ◽  
pp. 165-178 ◽  
Author(s):  
I.Philip Smith ◽  
Neil B. Metcalfe ◽  
Felicity A. Huntingford ◽  
Sunil Kadri
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Feeding Behaviour ◽  
Seasonal Patterns ◽  
Atlantic Salmon Salmo Salar ◽  
Sea Cage

Genetic Divergence of Anadromous and Nonanadromous Atlantic Salmon (Salmo salar) in the River Namsen, Norway

1989 ◽  
Vol 46 (3) ◽  
pp. 406-409 ◽  
Author(s):  
Jukka Vuorinen ◽  
Ole Kristian Berg
Keyword(s):  
Life History ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Genetic Divergence ◽  
Gene Diversity ◽  
Atlantic Salmon Salmo Salar ◽  
Large Numbers ◽  
Salmon Fry ◽  
Strong Founder Effect ◽  
Electrophoretic Data

Anadromous and nonanadromous Atlantic salmon, Salmo salar, coexist in the River Namsen in Norway. We studied genetic divergence between these two life history types by using electrophoretic data from 38 protein loci. Although allele frequencies differed significantly between the types at four loci no fixed allele frequency difference was observed. Nei's genetic distance between the life history types, however, was 0.01 a relatively high value for Atlantic salmon populations. The genetic differences observed between anadromous and nonanadromous salmon accounted for 18.3% of the total gene diversity. The five nonanadromous salmon samples formed two genetically different groups corresponding to the upper and lower ranges of the nonanadromous salmon in the river. The average observed heterozygosity was 3.1% for anadromous and 1.0% for nonanadromous salmon. The low heterozygosity in nonanadromous salmon probably reflects a strong founder effect. Stockings of large numbers of anadromous salmon fry to the upper reaches of the River Namsen have caused no detectable hybridization with nonanadromous salmon. Also downstream migrating nonanadromous salmon have apparently not made any important genetic contribution to the anadromous fish.

scholarly journals Revisiting the restricted movement paradigm: the dispersal of Atlantic salmon fry from artificial redds

2020 ◽  
Author(s):  
Zachary J Eisenhauer ◽  
Paul M Christman ◽  
Jean-Michel Matte ◽  
William R. Ardren ◽  
Dylan J Fraser ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Restricted Movement ◽  
Salmon Fry ◽  
Salmon Eggs ◽  
Movement Strategy ◽  
Dispersal Curves ◽  
Dependent Growth ◽  
Dispersal Distances ◽  
New Habitats

The Restricted Movement Paradigm (RMP) asserts that stream fishes are sedentary, living much of their lives within a single reach. To test the RMP, we implanted eyed Atlantic salmon eggs (Salmo salar L.) into a total of 19 artificial redds, in seven salmon-free streams, in six years, and estimated summer fry dispersal through electrofishing surveys. As expected, most fry dispersed downstream, but an average of 35% moved upstream. Surprisingly, fry moved just as far upstream as downstream (medians = 403 and 404 m, respectively). Fry were larger at lower densities and farther from redd sites, consistent with density-dependent growth, and larger upstream than downstream, possibly indicating that larger fry were better able to move upstream against the current. Dispersal distances were normally distributed around all but two of 19 redds, and half of the downstream dispersal curves were best described by unimodal distributions, consistent with a homogeneous movement strategy. Our data suggest that salmon fry were more mobile and move upstream more than previously thought, which should facilitate their stocking or reintroduction to new habitats.

Pathogenesis of Infectious Pancreatic Necrosis in Atlantic Salmon (Salmo salar)

1979 ◽  
Vol 36 (5) ◽  
pp. 587-591 ◽  
Author(s):  
Robert N. Swanson ◽  
James H. Gillespie
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Pancreatic Necrosis ◽  
Virus Concentration ◽  
Live Virus ◽  
Atlantic Salmon Salmo Salar ◽  
Salmon Fry ◽  
Infectious Pancreatic Necrosis ◽  
Low Levels ◽  
Acinar Tissue

Atlantic salmon (Salmo salar) fry and yearling were found to undergo an active but subclinical infection following exposure to infectious pancreatic necrosis (IPN) virus. Eight-week-old Atlantic salmon fry were fed live virus and the mortality and virus concentration in these fry were recorded over a period of 78 d following exposure. Yearling Atlantic salmon were inoculated intraperitoneally with IPN virus and the concentration of virus in the pancreas–intestine, kidneys, spleen, liver, and gonads of inoculated fish was determined over a period of 74 d following inoculation. Virus first appeared in the fry 3 d postinoculation (DPI) and virus titers reached a peak by 8 DPI. Low levels of virus persisted in fry sampled 78 DPI. Virus first appeared in the pancreas–intestine of Atlantic salmon 12 h postinoculation (HPI) and was detected in the kidneys, liver, and spleen by 72 HPI. Peak virus titers were reached in the pancreas–intestine by 72 HPI. Both the pancreas–intestine and kidneys continued to support viral growth frequently and appeared to be important reservoirs of virus. At no time was virus isolated from the gonads of inoculated yearling. Histological examination of yearlings revealed degenerative changes in the pancreatic acinar tissue and in some cases focal necrosis in the liver. No histological abnormalities were found in IPN-infected fry. Key words: infectious pancreatic necrosis, Atlantic salmon, virus, histology

Parr–Smolt Transformation in Female and Sexually Mature Male Anadromous and Nonanadromous Atlantic Salmon, Salmo salar

1986 ◽  
Vol 43 (3) ◽  
pp. 680-686 ◽  
Author(s):  
Tim P. Birt ◽  
John M. Green
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Condition Factor ◽  
Total Lipid Content ◽  
Chloride Cell ◽  
Mature Male ◽  
Seasonal Patterns ◽  
Atlantic Salmon Salmo Salar ◽  
Sexually Mature ◽  
Mature Male Parr

The parr–smolt transformation was compared in cultured Newfoundland male and female anadromous and nonanadromous Atlantic salmon, Salmo salar. Seasonal patterns of decreasing total lipid content and condition factor accompanied by increasing moisture content, silvering, and branchial Na+-K+ ATPase activity indicate that smoltification occurred only in immature anadromous females. Previously mature anadromous males did not smoitify. In general, smoltification did not occur in nonanadromous salmon. Chloride cell length did not increase in any group with smoltification. The lack of smoltification in previously mature male parr of anadromous stock is consistent with reports of small numbers of male salmon in smolt runs in many Newfoundland rivers.

Microhabitat use by juvenile Atlantic salmon (Salmo salar ) sheltering during the day in summer

1998 ◽  
Vol 76 (8) ◽  
pp. 1441-1449 ◽  
Author(s):  
Gabe Gries ◽  
Francis Juanes
Keyword(s):  
Atlantic Salmon ◽  
Water Column ◽  
Salmo Salar ◽  
Maximum Temperature ◽  
Juvenile Salmon ◽  
Microhabitat Use ◽  
Atlantic Salmon Salmo Salar ◽  
Juvenile Atlantic Salmon ◽  
Young Of The Year ◽  
And Behavior

Daytime snorkeling surveys were conducted in the Wardsboro Branch, a tributary of the West River, Vermont, U.S.A., in July and August 1996. We documented microhabitat use by 245 juvenile Atlantic salmon (Salmo salar) sheltering (i.e., concealed beneath the stream substrate) at water temperatures ranging from 17 to 23°C, well above 10°C, the maximum temperature at which young salmon are thought to shelter during the day. The majority (92%) of sheltering salmon were young-of-the-year salmon (YOY). Of the YOY observed, 45% were sheltering, while 55% were in the water column. In comparison, only 10% of post-young-of-the-year salmon (PYOY; age 1 or older) observed were sheltering, while 90% were in the water column. Sheltering PYOY occupied greater water depths and were found under larger substrate stones than were YOY. Sheltering salmon (YOY and PYOY) were not distributed in proportion to the available microhabitat. Salmon only sheltered beneath unembedded cobble or boulder substrate, and sheltering salmon were found in pool habitats 43% of the time. Daytime sheltering suggests that the current interpretation of juvenile salmon habitat use and behavior during summer is incomplete. The availability of suitable sheltering habitats may be a factor affecting juvenile salmon production.

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