Optimal Time and Size for Smolt Migration in Wild Sea Trout (Salmo trutta)

A tagging programme, in which wild sea trout (Salmo trutta) were marked at the parr stage with internal tags in winter and recaptured during smolt migration in a trap in the following spring, was conducted for three seasons in a small stream in southwestern Sweden, individuals that were initially smaller migrated later, grew more in length, and were smaller at migration than those initially bigger. Body length at migration decreased with migration time during the season for tagged as well as nontagged trout. A model for optimal time of and size at migration is proposed, based on the assumption that the expression (body length at the end of the season) × (survival over the season) is maximized and that migratory and postmigratory survival is positively size dependent. The qualitative predictions on the relationship between initial size and time of and size at migration are supported by the tagging data. Pre- and postmigratory growth rates are predicted to have opposite effects on migration time, so the migration timing is expected to depend strongly on the degree of dependence between these.

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Temporal Changes in the Spatial Distribution of Juvenile Sea-Trout Salmo trutta in a Small Stream

Oikos ◽

10.2307/3543531 ◽

1978 ◽

Vol 30 (1) ◽

pp. 114 ◽

Cited By ~ 17

Author(s):

Torgny Bohlin

Keyword(s):

Spatial Distribution ◽

Salmo Trutta ◽

Temporal Changes ◽

Small Stream ◽

Sea Trout

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Temporal and spatial patterns of sea lice levels on sea trout in western Scotland in relation to fish farm production cycles

Biology Letters ◽

10.1098/rsbl.2009.0872 ◽

2010 ◽

Vol 6 (4) ◽

pp. 548-551 ◽

Cited By ~ 14

Author(s):

S. J. Middlemas ◽

J. A. Raffell ◽

D. W. Hay ◽

M. Hatton-Ellis ◽

J. D. Armstrong

Keyword(s):

Atlantic Salmon ◽

Salmo Trutta ◽

Wild Fish ◽

Sea Lice ◽

Production Cycle ◽

Sea Trout ◽

Farm Production ◽

Production Cycles ◽

Temporal And Spatial ◽

The Relationship

The relationship between aquaculture and infestations of sea lice on wild sea trout ( Salmo trutta ) populations is controversial. Although some authors have concluded that there is a link between aquaculture and lice burdens on wild fish, others have questioned this interpretation. Lice levels have been shown to be generally higher on Atlantic salmon farms during the second years of two-year production cycles. Here we investigate whether this pattern relates to lice burdens on wild fish across broad temporal and spatial axes. Within Loch Shieldaig across five successive farm cycles from 2000 to 2009, the percentage of sea trout with lice, and those above a critical level, were significantly higher in the second year of a two-year production cycle. These patterns were mirrored in 2002–2003 across the Scottish west coast. The results suggest a link between Atlantic salmon farms and sea lice burdens on sea trout in the west of Scotland.

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Density-dependent and density-independent growth in a population of juvenile sea-trout,Salmo trutta, assessed using long-term data from a small stream in Northwest England

Freshwater Biology ◽

10.1111/fwb.12493 ◽

2014 ◽

Vol 60 (2) ◽

pp. 336-346 ◽

Cited By ~ 3

Author(s):

J. M. Elliott

Keyword(s):

Salmo Trutta ◽

Small Stream ◽

Density Dependent ◽

Sea Trout ◽

Term Data

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Ecological Significance of Differences in Frequency of White Fin Margins Among Four Brown Trout (Salmo trutta) Populations

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f88-152 ◽

1988 ◽

Vol 45 (7) ◽

pp. 1304-1309 ◽

Cited By ~ 1

Author(s):

Trend Taugbøl ◽

Jostein Skurdal ◽

Ragnvald Andersen

Keyword(s):

Brown Trout ◽

Salmo Trutta ◽

Selective Pressure ◽

Territorial Behavior ◽

Ecological Significance ◽

Low Frequencies ◽

Small Stream ◽

Sea Trout ◽

Open Sea ◽

Brown Trout Salmo Trutta

The frequency of distinct white fin margins was investigated in four brown trout (Salmo trutta) populations, living in the small stream Austadbekken (anadromous and stream resident) and in Lake Selura (lake and stream spawners). The frequency varied within and among populations. White margins were most common among parr and mature residents from Austadbekken. Sea trout had very low frequencies compared with parr and mature residents from the same population. Among stream spawners from Lake Selura (which stay the first 0–2 yr in the stream), white margins were less frequent than in Austadbekken; lake spawners (which spend their entire life in the lake) had even fewer. While a previous author stated that white fin margins were under genetic control, our observations indicate that the environment can affect the coloration. We hypothesize that white fin margins play a role in territorial behavior and are developed strongly where territorial behavior is pronounced, i.e. in stream- and river-dwelling trout. There may be a selective pressure, favoring easily seen signals showing that a territory is occupied so that energy-demanding fights can be avoided. In open sea and estuaries where predators are frequent, conspicuous fin margins may be a disadvantage due to greater predation risks.

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Present Status of the Salmonids Atlantic Salmon and Sea-Trout in the Dutch Part of the River Rhine

Water Science & Technology ◽

10.2166/wst.1994.0057 ◽

1994 ◽

Vol 29 (3) ◽

pp. 37-41 ◽

Cited By ~ 7

Author(s):

W. G. Cazemier

Keyword(s):

Atlantic Salmon ◽

Salmo Trutta ◽

Natural Populations ◽

River Rhine ◽

Sea Trout ◽

The Past ◽

The North ◽

Trout Population ◽

The North Sea ◽

Heavy Pollution

In the past, the anadromous salmonids, Atlantic salmon (Salmo salar) and sea-trout (Salmo trutta), have formed natural populations in the river Rhine. From the beginning of the nineteenth century onwards, the greater part of the drainage area of the river has been gradually altered from a more or less rural and agricultural area, into a highly industrialised one with subsequent industrialisation, river-engineering and heavy pollution. These developments are considered to be the major cause for the disappearance of the populations of anadromous salmonid fish in the 1950s. The water quality has recovered significantly during the past 25 years. From about 1975 onwards, this process gave rise to a recovery of the anadromous trout population. Results of recent studies of the sea-trout migration pattern are presented. They reveal that nowadays these salmonids can complete their up- and downstream migrations from the North Sea to places, situated at hundreds of kilometres upward the river and vica versa. The numbers of recorded Atlantic salmon and catch locations in inland waters are presented. They show a significant increase since 1989. These phenomena can be understood as promising signs of the recovery of the Rhine aquatic ecosystem.

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Purification and characterization of the carbonic anhydrase enzyme from Black Sea trout (Salmo trutta Labrax Coruhensis) kidney and inhibition effects of some metal ions on enzyme activity

Environmental Toxicology and Pharmacology ◽

10.1016/j.etap.2016.04.011 ◽

2016 ◽

Vol 44 ◽

pp. 134-139 ◽

Cited By ~ 75

Author(s):

Murat Kucuk ◽

İlhami Gulcin

Keyword(s):

Enzyme Activity ◽

Carbonic Anhydrase ◽

Metal Ions ◽

Black Sea ◽

Salmo Trutta ◽

Purification And Characterization ◽

Sea Trout ◽

Carbonic Anhydrase Enzyme

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An examination of the PCB: lipid relationship among individual fish

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f97-014 ◽

1997 ◽

Vol 54 (5) ◽

pp. 1031-1038

Author(s):

C A Stow ◽

L J Jackson ◽

J F Amrhein

Keyword(s):

Salmo Trutta ◽

Lake Michigan ◽

Oncorhynchus Tshawytscha ◽

Lake Trout ◽

Coho Salmon ◽

Salvelinus Namaycush ◽

Rainbow Trout Oncorhynchus Mykiss ◽

Strong Linear Correlation ◽

Brown Trout Salmo Trutta ◽

The Relationship

We examined data from 1984 to 1994 for five species of Lake Michigan salmonids to explore the relationship between total PCB concentration and percent lipid. When we compared mean species lipid and PCB values, we found a strong linear correlation. When we compared values among individuals, we found modest positive PCB:lipid associations in brown trout (Salmo trutta), chinook salmon (Oncorhynchus tshawytscha), coho salmon (Oncorhynchus kisutch), and rainbow trout (Oncorhynchus mykiss) collected during spawning, but positive associations were not apparent among nonspawning individuals. Lake trout (Salvelinus namaycush) exhibited no discernible PCB:lipid relationship. Our results are not incompatible with previous observations that contaminants are differentially partitioned into lipids within a fish, but these results do suggest that lipids are not a major factor influencing contaminant uptake.

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