Seasonal Activity and Feeding Pattern of Brown Trout (Salmo trutta) in a Dartmoor Stream in Relation to Availability of Food

1969 ◽  
Vol 26 (8) ◽  
pp. 2165-2171 ◽  
Author(s):  
I. Chaston
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Stomach Contents ◽  
Total Activity ◽  
The Other ◽  
Brown Trout Salmo Trutta ◽  
The Difference ◽  
The Times ◽  
Maximum Occurrence ◽  
Terrestrial Material

In laboratory tests, brown trout were most active between dusk and dawn from spring to autumn, but the percentage of the total activity that occurred during daylight was higher in the summer than in the other two seasons. Analysis of the variation in the weight of stomach contents during 24 hr in the three seasons showed a higher peak in weight at noon in summer than in the other seasons. The difference was related to an increased consumption of material of terrestrial origin, which other work showed to be most available to the fish between 09.00 and 12.00 hr. No relationship was found between the times of maximum occurrence of benthic and emergent items in the stream and of their consumption by trout. The increase in daytime activity during the summer was also evidently related to increased consumption of terrestrial material.

Effects of brown trout, Salmo trutta L., on the distribution of some native fishes in three areas of southern Victoria

1980 ◽  
Vol 31 (1) ◽  
pp. 61 ◽  
Author(s):  
PD Jackson ◽  
WD Williams
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
The Other ◽  
Circumstantial Evidence ◽  
Native Fish ◽  
Introduced Fish ◽  
Brown Trout Salmo Trutta ◽  
Native Fishes ◽  
Yarra River

Eight species of native fish and two of introduced fish were found during studies of the distribution of fishes in streams in three areas of southern Victoria; namely in the upper part of the catchment of the Yarra River, in the Otway Ranges, and on Wilsons Promontory. S. trutta does not occur on Wilsons Promontory, but does occur in the other two areas. Results provide circumstantial evidence that S. trutta has deleteriously affected the occurrence of Galaxias olidus and possibly G. brevipinnis. Some native fishes appear able to coexist with S. trutta.

scholarly journals Assessment of metal contamination in the upper reaches of the Tichá Orlice River

2011 ◽  
Vol 49 (No. 10) ◽  
pp. 458-464 ◽  
Author(s):  
Z. Svobodová ◽  
O. Čelechovská ◽  
J. Kolářová ◽  
T. Randák ◽  
V. Žlábek
Keyword(s):  
Muscle Tissue ◽  
Brown Trout ◽  
Metal Contamination ◽  
Salmo Trutta ◽  
Anthropogenic Source ◽  
Contamination Assessment ◽  
Mercury Compounds ◽  
Brown Trout Salmo Trutta ◽  
The Difference ◽  
Cadmium Lead

The aim of the present study was to assess metal contamination in the same reaches of the river, and thus to help explain unsatisfactory reproduction results in the reproduction of salmonoid fish. The contamination assessment was based on measuring metal concentrations in the brown trout (Salmo trutta morpha fario) and some bottom sediment samples. The samples were collected in June 2000 and 2001 at two collection sites from theTicháOrliceRiver (Červená Voda – 103rd river km; Lichkov – 93rd river km) and its tributary Kralický Brook (100th river km). At each of the sites, 14 brown trouts were collected in each of the periods of monitoring. The AAS method was used to determine the total mercury, arsenic, cadmium, lead, copper, zinc, chromium and nickel contents in the muscle tissue of the fish and in aquatic sediments. The Kralický Brook is an important anthropogenic source of metal contamination (particularly of mercury and copper) for theTicháOrliceRiver. The highest concentrations of mercury in muscles of brown trout were found at the Kralický Brook (0.37 ± 0.08 and 0.40 ± 0.08 mg/kg) and Lichkov (0.41 ± 0.10 and 0.34 ± 0.07 mg/kg) in 2000 and 2001 and the lowest concentration at Červená Voda (0.017 ± 0.02 mg/kg in the same years). Significantly higher concentrations of arsenic (in 2000: 0.30 ± 0.08 mg/kg; in 2001: 0.38 ± 0.07 mg/kg) were found in the muscle tissue of the brown trout collected at Červená Voda than at the downstream site Lichkov (in 2000: 0.18 ± 0.09 mg/kg;in 2001: 0.14 ± 0.07 mg/kg). The authors hypothesize that the difference was due to different conditions (principally water temperature). It seems reasonable to assume that unsatisfactory results in the reproduction of fish from the upper reaches of theTicháOrliceRiver are due not only to organic pollutants but also to mercury compounds that are classified among suspect endocrine disruptors.  

Spawning of Escaped Farmed Atlantic Salmon (Salmo salar): Hybridization of Females with Brown Trout (Salmo trutta)

1993 ◽  
Vol 50 (9) ◽  
pp. 1986-1990 ◽  
Author(s):  
A. F. Youngson ◽  
J. H. Webb ◽  
C. E. Thompson ◽  
D. Knox
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Brown Trout ◽  
Salmo Trutta ◽  
F1 Hybrids ◽  
Fish Farms ◽  
Atlantic Salmon Salmo Salar ◽  
Brown Trout Salmo Trutta ◽  
The Difference ◽  
Farmed Atlantic Salmon

Atlantic salmon (Salmo salar) and F1 hybrids between Atlantic salmon and brown trout (Salmo trutta) were distinguished among juvenile salmonids sampled at emergence from rivers in western and northern Scotland. Hybrids were present in samples obtained from seven of the 16 rivers examined. Salmon fry and hybrid fry that were demonstrably the progeny of female salmon that had escaped from fish farms were identified by detecting the presence of maternal canthaxanthin, a synthetic flesh colorant, in the juveniles' pigment load. Canthaxanthin was detected in 101 (4%) of the 2350 salmon and eight (35%) of the 23 hybrids examined. The difference in the frequencies of salmon and hybrids carrying canthaxanthin was significant. Escaped female salmon hybridized with trout more frequently than did wild females.

scholarly journals Ultraviolet reflection enhances the risk of predation in a vertebrate

2013 ◽  
Vol 59 (2) ◽  
pp. 151-159 ◽  
Author(s):  
Ricarda Modarressie ◽  
Ingolf P. Rick ◽  
Theo C. M. Bakker
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Gasterosteus Aculeatus ◽  
Brightness Discrimination ◽  
Physiological Model ◽  
Electromagnetic Spectrum ◽  
Uv Blocking ◽  
Risk Of Predation ◽  
Brown Trout Salmo Trutta ◽  
The Difference

Abstract Many animals are sensitive to ultraviolet light and also possess UV-reflective regions on their body surface. Individuals reflecting UV have been shown to be preferred during social interactions such as mate choice or shoaling decisions. However, whether those body UV-reflections enhance also the conspicuousness to UV-sensitive predators and therefore entail costs for its bearer is less well documented. Two size-matched three-spined sticklebacks Gasterosteus aculeatus, one enclosed in a UV-transmitting (UV+) and another in a UV-blocking (UV-) chamber, were simultaneously presented to individual brown trout Salmo trutta. “yearlings”. Brown trout of this age are sensitive to the UV part of the electromagnetic spectrum and are natural predators of three-spined sticklebacks. The stickleback that was attacked first as well as the subsequent number of attacks was recorded. Sticklebacks enclosed in the UV-transmitting chamber were attacked first significantly more often compared to sticklebacks enclosed in the UV-blocking chamber. Control experiments using neutral density filters revealed that this was more likely due to UV having an influence on hue perception rather than brightness discrimination. The difference in attack probability corresponded to the difference in chromatic contrasts between sticklebacks and the experimental background calculated for both the UV+ and UVconditions in a physiological model of trout colour vision. UV reflections seem to be costly by enhancing the risk of predation due to an increased conspicuousness of prey. This is the first study in a vertebrate, to our knowledge, demonstrating direct predation risk due to UV wavelengths.

Contrasting predation risks presented by introduced brown trout and native common river galaxias in New Zealand streams

1995 ◽  
Vol 52 (9) ◽  
pp. 1821-1833 ◽  
Author(s):  
Angus R. McIntosh ◽  
Colin R. Townsend
Keyword(s):  
New Zealand ◽  
Predation Risk ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Visual Cues ◽  
Prey Availability ◽  
Stomach Contents ◽  
River System ◽  
Brown Trout Salmo Trutta ◽  
Nocturnal Increase

Alterations in the predation risk affecting macroinvertebrates in streams of the Taieri River system of New Zealand were assessed following the replacement of native common river galaxias (Galaxias vulgaris) in many sites by introduced brown trout (Salmo trutta). In laboratory channels, galaxias foraged on mayfly nymphs from benthic positions; they searched for prey at night but stayed in cover during the day except when attacking prey. Trout foraged from positions in the water column during day and night. There were no diel differences in foraging by galaxias but trout had higher reaction distances and consumed more during the day. No diel pattern was found in trout stomach contents in the field, probably because of a nocturnal increase in prey availability. Trout and galaxias populations in the field consumed similar biomasses of aquatic prey. However, these experiments indicate there have been subtle changes in the predation regime. Trout relied on visual cues to capture prey so predation risk was higher during the day and larger prey items were more at risk. In comparison, galaxias relied more on mechanical cues to capture prey and predation risk was similar during day and night.

Considerations on the vulnerability of the Eurasian water shrew Neomys fodiens to the presence of introduced brown trout Salmo trutta

Biologia ◽  
2016 ◽  
Vol 71 (6) ◽  
Author(s):  
Rocco Tiberti ◽  
Emiliano Mori
Keyword(s):  
Brown Trout ◽  
Aquatic Ecosystems ◽  
Salmo Trutta ◽  
The Other ◽  
Introduced Fish ◽  
Major Threat ◽  
Other Hand ◽  
Brown Trout Salmo Trutta ◽  
Semiaquatic Mammals ◽  
Neomys Fodiens

AbstractIntroduced fish represent a major threat for aquatic ecosystems and species and their impact on semiaquatic vertebrates, such as amphibians, has been extensively studied. On the other hand, little is known about their impact on semiaquatic mammals, such as water shrews (

Interactions of slimy sculpin (Cottus cognatus) with native and nonnative trout: consequences for growth

2006 ◽  
Vol 63 (7) ◽  
pp. 1526-1535 ◽  
Author(s):  
Julie KH Zimmerman ◽  
Bruce Vondracek
Keyword(s):  
Brown Trout ◽  
Brook Trout ◽  
Salmo Trutta ◽  
Single Species ◽  
Cottus Cognatus ◽  
Slimy Sculpin ◽  
Brown Trout Salmo Trutta ◽  
The Difference ◽  
Juvenile Brown Trout ◽  
Potential Interactions

We examined growth of native slimy sculpin (Cottus cognatus), native brook trout (Salvelinus fontinalis), and nonnative brown trout (Salmo trutta) to investigate potential interactions of a native nongame fish with native and nonnative trout. Enclosures (1 m2) were stocked with five treatments (juvenile brown trout with sculpin, juvenile brook trout with sculpin, and single species controls) at three densities. Treatments (with replication) were placed in riffles in Valley Creek, Minnesota, and growth rates were measured for six experiments. We examined the difference in growth of each species in combined species treatments compared with each species alone. We did not find evidence of inter actions between brook trout and sculpin, regardless of density or fish size. However, sculpin gained greater mass when alone than with brown trout when sculpin were >16 g. Likewise, brown trout grew more when alone than with sculpin when brown trout were >24 g. In contrast, brown trout ≤5 g grew more with sculpin compared with treatments alone. We suggest that native brook trout and sculpin coexist without evidence of competition, whereas nonnative brown trout may compete with sculpin.

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