scholarly journals The response of a brown trout (Salmo trutta) population to reintroduced Eurasian beaver (Castor fiber) habitat modification

2021 ◽  
pp. 1-11
Author(s):  
Robert J. Needham ◽  
Martin Gaywood ◽  
Angus Tree ◽  
Nick Sotherton ◽  
Dylan Roberts ◽  
...  
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Low Cost ◽  
Fork Length ◽  
Freshwater Ecosystems ◽  
Habitat Modification ◽  
Castor Fiber ◽  
Suitable Habitat ◽  
Eurasian Beaver ◽  
Brown Trout Salmo Trutta

Globally, freshwaters are the most degraded and threatened of all ecosystems. In northern temperate regions, beaver (Castor spp.) reintroductions are increasingly used as a low-cost and self-sustaining means to restore river corridors. River modifications by beavers can increase availability of suitable habitat for fish, including salmonids. This study investigated the response of a population of brown trout (Salmo trutta) to reintroduced Eurasian beaver (Castor fiber) habitat modifications in northern Scotland. The field site comprised two streams entering a common loch; one modified by beavers, the other unaltered. Electrofishing and PIT telemetry surveys indicated abundance of post-young-of-the-year (post-YOY) trout was higher in the modified stream. Considering juvenile year groups (YOY and post-YOY) combined, abundance and density varied with year and season. In the modified stream, fork length and mass were greater, there was a greater variety of age classes, and mean growth was positive during all seasons. Beavers had profound effects on the local brown trout population that promoted higher abundances of larger size classes. This study provides important insight into the possible future effect of beavers on freshwater ecosystems.

scholarly journals Assessing the suitable habitat for reintroduction of brown trout (Salmo trutta forma fario ) in a lowland river: A modeling approach

2018 ◽  
Vol 8 (10) ◽  
pp. 5191-5205
Author(s):  
Pieter Boets ◽  
Sacha Gobeyn ◽  
Alain Dillen ◽  
Eddy Poelman ◽  
Peter L. M. Goethals
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Suitable Habitat ◽  
Lowland River ◽  
Modeling Approach ◽  
Brown Trout Salmo Trutta

Unravelling the effects of water temperature and density dependence on the spatial variation of brown trout (Salmo trutta) body size

2012 ◽  
Vol 69 (5) ◽  
pp. 821-832 ◽  
Author(s):  
Irene Parra ◽  
Ana Almodóvar ◽  
Daniel Ayllón ◽  
Graciela G. Nicola ◽  
Benigno Elvira
Keyword(s):  
Body Size ◽  
Spatial Variation ◽  
Density Dependence ◽  
Water Temperature ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Maximum Growth ◽  
Suitable Habitat ◽  
Brown Trout Salmo Trutta ◽  
Potential Maximum

This study looks at the relative influence of water temperature and density dependence on the spatial variation in body size of 126 brown trout ( Salmo trutta ) cohorts from 12 Iberian rivers over a 12-year period. Mean cohort mass and length of age groups 0+ to 2+ varied significantly among sampling sites because of the concurrent effect of water temperature and density dependence. Density in suitable habitat had a limiting role that influenced potential maximum growth of cohorts, and water temperature differentiated these cohorts in two groups of sites with high and low potential maximum growth. Water temperature had a positive cumulative effect on body size of all age classes. However, body size of age-0 trout was nonlinearly influenced by short-term exposure to extreme water temperature. Thus, extremely high temperatures became a limiting factor and had deleterious effects on growth. There were intracohort and intercohort effects of density dependence throughout the life span, which were mainly due to the density in the available suitable habitat of trout of the same age or older. The present study supports the hypothesis that both density-dependent and density-independent processes are crucial for the understanding of population dynamics and that their relative importance varies across scales of space and time.

Age and growth properties of brown trout (Salmo trutta L.) living in Kan Stream, upper Çoruh River, Turkey

2007 ◽  
Vol 57 (3) ◽  
pp. 281-291 ◽  
Author(s):  
Murat Arslan ◽  
Ayhan Yildirim
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Growth Parameters ◽  
Fork Length ◽  
Total Weight ◽  
Age And Growth ◽  
Growth Properties ◽  
Brown Trout Salmo Trutta ◽  
Çoruh River ◽  
Male To Female

AbstractAge and growth were analyzed for brown trout from the Stream Kan, upper Çoruh River, from January 2001 to December 2001. Age varied between 0-7 years and the ratio of male to female was 1:1.05. Fork length and total weight for brown trout varied by 6.9-22.1 cm and 4.9-158.5 g for males, by 6.8-26.1 cm and 4.3-211.9 g for females, respectively. Fork length and total weight at the same age classes were not statistically significant between males and females. The highest specific growth rate occurred between age 1 and age 2 for both sexes. The von Bertalanffy equations were used to determine growth in length for both sexes and overall population separately. The growth parameters for males, females and overall population were estimated as L∞ = 32.5 cm, K = 0.169, t0 = −0.978, L∞ = 36.7 cm, K = 0.139, t0 = −1.065 and L∞ = 35.9 cm, K = 0.147, t0 = −1.002, respectively. Overall growth performance (ø) suggested that difference between the growth of brown trout from Kan stream and those from some other populations was found not statistically significant.

Low Toxicity of the Black Fly LarvicideBacillus thuringiensisvar.israelensisto Early Stages of Brook Trout (Salvelinus fontinalis), Brown Trout (Salmo trutta), and Steelhead Trout (Oncorhynchus my kiss) following Direct and Indirect Exposure

1994 ◽  
Vol 51 (6) ◽  
pp. 1451-1458 ◽  
Author(s):  
Mark S. Wipfli ◽  
Richard W. Merritt ◽  
William W. Taylor
Keyword(s):  
Brown Trout ◽  
Brook Trout ◽  
Salmo Trutta ◽  
Salvelinus Fontinalis ◽  
Fork Length ◽  
Scanning Electron Micrographs ◽  
Steelhead Trout ◽  
Brown Trout Salmo Trutta ◽  
Low Toxicity ◽  
Carbon Dioxide Levels

Mortality of brook trout (Salvelinus fontinalis), brown trout (Salmo trutta), and steelhead trout (Oncorhynchus mykiss) from eyed embryo to 82 mm fork length, exposed to Bacillus thuringiensis var. israelensis (B.t.i.) in the laboratory increased when dosages exceeded recommended rates by 12 000× or more. There was generally no toxicity difference between denatured (autoclaved) and nondenatured B.t.i. for all three trout species at all B.t.i. concentrations tested, indicating that mortality was due to formulation components and not B.t.i. toxin. The 48-h LC50values for brown and brook trout alevins ranged from 1561 to 2321 ppm for both denatured and nondenatured B.t.i. Scanning electron micrographs showed particle and mucus accumulation on gill surfaces from fish exposed to 2000 ppm B.t.i. for 4 h. Oxygen and carbon dioxide levels in blood from exposed (4000 ppm B.t.i. for 4 h) and unexposed fish were similar. Brown trout of 43 mm fork length fed excess B.t.i.-killed or live black flies (Cnephia dacotensis) ate similar quantities of each larval type, and both groups experienced similar mortalities and growth rates at 30-d postexposure.

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