Intercohort competition effects on survival, movement, and growth of brown trout (Salmo trutta) in Swedish streams

2001 ◽  
Vol 58 (11) ◽  
pp. 2298-2308 ◽  
Author(s):  
Fredrik Nordwall ◽  
Ingemar Näslund ◽  
Erik Degerman
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Inverse Relationship ◽  
Apparent Survival ◽  
Older Immigrants ◽  
Small Streams ◽  
Competition Effects ◽  
Brown Trout Salmo Trutta ◽  
Mean Size ◽  
Reduced Data

The effects of density-dependent intercohort competition on growth and mortality in stream-resident brown trout (Salmo trutta) were tested by experimentally reducing the densities of age-1 fish and fish older than age 1 in six small streams. When densities of age-1 fish were reduced, abundance of age-0 and age-1 fish increased the following year, while age-1 fish experienced a reduced mean size. Reduced densities of fish older than age 1 resulted in increased apparent survival of age-0, age-1, and age-2 fish in the subsequent year. Mean size of age-2 fish increased as well. Many older immigrants (age >2) were found in the treatment sections where densities previously had been reduced. Data from the Swedish Electrofishing RegiSter (SERS) showed that mean body size of age-0 brown trout was negatively related to both age-0 and age >0 densities. The database also verified the inverse relationship between age-0 abundance and abundance of older cohorts. Our results indicate that intercohort competition regulates territorial fish populations, even when simple single populations in restricted environments are considered.

Spatial patterns in relations among brown trout (Salmo trutta) distribution, summer air temperature, and stream size in Rocky Mountain streams

1999 ◽  
Vol 56 (S1) ◽  
pp. 43-51 ◽  
Author(s):  
Frank J Rahel ◽  
Nathan P Nibbelink
Keyword(s):  
Spatial Patterns ◽  
Air Temperature ◽  
Brown Trout ◽  
Brook Trout ◽  
Salmo Trutta ◽  
Rocky Mountain ◽  
Thermal Window ◽  
Small Streams ◽  
Brown Trout Salmo Trutta ◽  
Stream Size

Stream size interacted with mean July air temperature to influence the distribution of brown trout (Salmo trutta) in southeastern Wyoming streams. The geographic range of brown trout was positively associated with mean July air temperatures of 19-22°C. Within this thermal zone, brown trout were more likely to occur in large streams (>4 m wetted width) than in small streams. We used a geographic information system to examine spatial patterns in the distribution of anomalous sites (i.e., sites predicted to have brown trout but which lacked this species). Sites that lacked brown trout but contained brook trout (Salvelinus fontinalis) tended to be on small streams at the cold margin of the 19-22°C thermal window. Sites lacking both brown trout and brook trout tended to be on small streams clustered in three of the six study drainages. The spatial aggregation of these sites suggests that additional regional factors influence the occurrence of brown trout in southeastern Wyoming. It is hypothesized that these factors could involve land-use practices interacting with basin geology and geomorphology. Classification models that incorporate a few general habitat factors are useful for identifying stream reaches with the potential to support brown trout and for directing management efforts to sites where this potential is not realized.

scholarly journals Within-stream phenotypic divergence in head shape of brown trout associated with invasive brook trout

2019 ◽  
Vol 129 (2) ◽  
pp. 347-355 ◽  
Author(s):  
Libor Závorka ◽  
Nicolas Larranaga ◽  
Magnus Lovén Wallerius ◽  
Joacim Näslund ◽  
Barbara Koeck ◽  
...  
Keyword(s):  
Brown Trout ◽  
Brook Trout ◽  
Native Species ◽  
Salmo Trutta ◽  
Morphological Changes ◽  
Foraging Strategies ◽  
The Novel ◽  
Head Shape ◽  
Apparent Survival ◽  
Brown Trout Salmo Trutta

Abstract Competition with a non-native species can lead to morphological changes in native organisms induced by phenotypic plasticity, and by selection against individuals that do not adjust their morphology to the novel selection pressure. The morphological changes in native organisms are often associated with rapid behavioural responses to competition with the invader. However, knowledge of the interaction between the behaviour and morphology of native organisms competing with a non-native species remains scarce. Here, we investigated the effect of competition with non-native brook trout Salvelinus fontinalis on head shape of native brown trout Salmo trutta in a stream system where changes in diet and territorial behaviour of sympatric brown trout have previously been demonstrated. We found that sympatric brown trout had smaller eyes, shorter lower jaws and more terminal mouth than allopatric conspecifics. These differences in head shape were highly repeatable over a period of 12 months. Apparent survival indicated that the selection on head shape of brown trout was weaker in the sympatric than in the allopatric stretch of the stream. The results suggest that these changes reinforce divergences of foraging strategies between the allopatric and sympatric brown trout, which can negatively affect their population dynamics and trophic function in the food-web.

Resistance of erythrocytes from Brown trout (Salmo trutta m. trutta L.) affected by ulcerative dermal necrosis syndrome

2011 ◽  
Vol 14 (3) ◽  
pp. 443-448 ◽  
Author(s):  
N. Kurhalyuk ◽  
H. Tkachenko ◽  
K. Pałczyńska
Keyword(s):  
Oxidative Stress ◽  
Lipid Peroxidation ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Thiobarbituric Acid ◽  
Control Group ◽  
Thiobarbituric Acid Reactive Substance ◽  
Tbars Level ◽  
Reactive Substance ◽  
Brown Trout Salmo Trutta

Resistance of erythrocytes from Brown trout (Salmo trutta m. trutta L.) affected by ulcerative dermal necrosis syndrome In the present work we evaluated the effect of ulcerative dermal necrosis (UDN) syndrome on resistance of erythrocytes to haemolytic agents and lipid peroxidation level in the blood from brown trout (Salmo trutta m. trutta L.). Results showed that lipid peroxidation increased in erythrocytes, as evidenced by high thiobarbituric acid reactive substance (TBARS) levels. Compared to control group, the resistance of erythrocytes to haemolytic agents was significantly lower in UDN-positive fish. Besides, UDN increased the percent of hemolysated erythrocytes subjected to the hydrochloric acid, urea and hydrogen peroxide. Results showed that UDN led to an oxidative stress in erythrocytes able to induce enhanced lipid peroxidation level, as suggested by TBARS level and decrease of erythrocytes resistance to haemolytic agents.

Evaluation of brown trout (Salmo trutta fario) fillets’ shelf life: Fed with a humic supplemented diet

2021 ◽  
Vol 29 ◽  
pp. 100675
Author(s):  
Muhammed Atamanalp ◽  
Arzu Ucar ◽  
Esat Mahmut Kocaman ◽  
Gonca Alak
Keyword(s):  
Shelf Life ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Brown Trout Salmo Trutta ◽  
Salmo Trutta Fario
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