An experimental evaluation of competitive and thermal effects on brown trout (Salmo trutta) and Bonneville cutthroat trout (Oncorhynchus clarkii utah) performance along an altitudinal gradient

2005 ◽  
Vol 62 (12) ◽  
pp. 2784-2795 ◽  
Author(s):  
Peter McHugh ◽  
Phaedra Budy
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Abiotic Factors ◽  
Cutthroat Trout ◽  
Reverse Direction ◽  
Mountain Stream ◽  
Oncorhynchus Clarkii ◽  
Treatment Groups ◽  
Brown Trout Salmo Trutta ◽  
Bonneville Cutthroat Trout

Temperature-mediated competition (i.e., dominance shifts between species depending on temperature) may explain the segregation of salmonid species along altitudinal stream gradients. We evaluated this hypothesis for exotic brown trout (Salmo trutta) and native Bonneville cutthroat trout (Oncorhynchus clarkii utah) by rearing them in experimental sympatry and allopatry using enclosures constructed at six sites spaced along a 45-km segment of a mountain stream. For both species, we compared condition and growth between allopatric and sympatric treatment groups. We found that brown trout negatively affected cutthroat trout performance, whereas cutthroat trout failed to impart an effect in the reverse direction, regardless of temperature. Thus, we documented asymmetric competition between these species but found little evidence indicating that its outcome was influenced by temperature. Brown trout – cutthroat trout segregation is therefore unlikely to be due to temperature-mediated competition. Instead, brown trout may have displaced cutthroat trout from downstream areas through competition or other mechanisms, while abiotic factors preclude their (brown trout) invasion of upper elevations. Given the magnitude of effect observed in our study, we recommend that brown trout receive greater consideration in cutthroat trout conservation.

scholarly journals Application of multistate modeling to estimate salmonid survival and movement in relation to spatial and temporal variation in metal exposure in a mining-impacted river

2019 ◽  
Vol 76 (11) ◽  
pp. 2057-2068
Author(s):  
Mariah P. Mayfield ◽  
Thomas E. McMahon ◽  
Jay J. Rotella ◽  
Robert E. Gresswell ◽  
Trevor Selch ◽  
...  
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Survival Rates ◽  
Cutthroat Trout ◽  
Spatial And Temporal Variation ◽  
Metal Exposure ◽  
Westslope Cutthroat Trout ◽  
Aquatic Life ◽  
Oncorhynchus Clarkii ◽  
Brown Trout Salmo Trutta

Multistate modeling was used to estimate survival and movement of brown trout (Salmo trutta) and westslope cutthroat trout (Oncorhynchus clarkii lewisi) in relation to copper concentrations in the mining-impacted Clark Fork River, Montana. Survival probability in the uppermost river segment, where dissolved copper concentrations frequently exceeded acute criteria for aquatic life (range: 31–60 days > 13.4 μg·L–1), was 2.1 times lower for brown trout and 122 times lower for westslope cutthroat trout compared with survival rates in the lowermost segment that had relatively low dissolved copper (0 days exceedance of acute concentration). Lowest survival for both species occurred in the spring–summer period when dissolved copper concentrations were elevated coincident with higher discharge. Movement among study segments was generally low, and cutthroat trout showed low movement into the uppermost river segment with the most elevated copper levels. Both species showed high rates of movement into tributaries, which coincided with their respective spawning migrations rather than as an apparent avoidance of elevated copper levels. The linkage between survival rate and level of copper exposure for both trout species suggests that additional removal of tailings deposits could improve survival rates.

scholarly journals Remarkable differences in the presence of the acanthocephalan parasite Echinorhynchus truttae in brown trout (Salmo trutta) captured in two adjacent river basins in Galicia (NW Spain)

2018 ◽  
Vol 4 ◽  
Author(s):  
Seila Couso-Pérez ◽  
Antonio Cañizo-Outeiriño ◽  
Rainer Campo-Ramos ◽  
Elvira Ares-Mazás ◽  
Hipólito Gómez-Couso
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Anthropogenic Activities ◽  
Abiotic Factors ◽  
River Basins ◽  
Brown Trout Salmo Trutta ◽  
Western Spain ◽  
Acanthocephalan Parasite ◽  
North Western ◽  
Crustacean Host

Abstract This is the first report on the presence of acanthocephalan parasite Echinorhynchus truttae in brown trout (Salmo trutta) from Spain. A total of 343 fish were captured by local anglers from 19 rivers in the adjacent Tambre and Ulla watersheds in Galicia (north-western Spain). Macroscopic and microscopic analyses of the intestinal contents revealed the presence of adults and/or eggs of E. truttae in 53 of the 123 trout from Tambre river basin (43.1%). By contrast, parasitic forms of this acanthocephalan were only observed in eight of the 220 fish from Ulla basin (3.6%), showing significant differences between the prevalences obtained in two adjacent watersheds (P < 0.001, odds ratio 19.0). Prevalence was significantly higher in specimens >3 years (length >26.0 cm) than in younger specimens (P < 0.05). The absence of Gammarus pulex in the region suggests that native gammarid species in Galicia (Echinogammarus lusitanicus and Echinogammarus beriyoni) may act as intermediate host in the life cycle of E. truttae. Different prevalences of E. truttae indicate that the presence/abundance of the intermediate crustacean host may be different in the two river basins, probably as a consequence of various abiotic factors and anthropogenic activities.

Multispecies and Watershed Approaches to Freshwater Fish Conservation

2019 ◽  
Keyword(s):  
Salmo Trutta ◽  
Cutthroat Trout ◽  
Fish Passage ◽  
Main Stem ◽  
Conservation Action ◽  
Oncorhynchus Clarkii ◽  
Water Users ◽  
Utility Companies ◽  
Bluehead Sucker ◽  
Bonneville Cutthroat Trout

<em>Abstract</em>—The Weber River is primarily known as a blue-ribbon Brown Trout <em>Salmo trutta </em>fishery; however, this river also supports populations of two jeopardized fishes, Bonneville Cutthroat Trout <em>Oncorhynchus clarkii utah </em>and Bluehead Sucker <em>Catostomus discobolus</em>. At least one population of Bonneville Cutthroat Trout in the Weber River provides an important and popular local fishery and expresses a fluvial life history where main-stem individuals grow large (300–500 mm total length) and migrate into small tributaries for spawning. Bluehead Suckers currently occur in the main stem of the Weber River, where they travel distances of 20 km between spawning and overwintering habitats. The habitat for both species has been fragmented by more than 300 barriers composed of irrigation diversions, road crossings, and utility stream crossings. Beginning in 2010, the Utah Division of Wildlife Resources and Trout Unlimited began undertaking barrier removal for native fish as a priority conservation action. Initially, the effort to reconnect habitat was slow and the lack of relationships with stakeholders such as water users, government agencies, private landowners, and utility companies was hampering progress with habitat reconnection. New barriers were being built at a faster rate than barriers were being removed. To build these relationships, a steering committee was formed to secure a small grant, hire a consulting firm, organize stakeholder meetings to identify broad stakeholder priorities, and write a watershed plan that ultimately identified Bonneville Cutthroat Trout and Bluehead Sucker as priority conservation targets. The watershed plan and subsequent stakeholder meetings developed a framework for the Weber River Partnership. The partnership holds an annual symposium where larger watershed issues are discussed. The symposium also provides a platform where all stakeholders can understand the activities occurring throughout the watershed and where there are opportunities to collaborate. The Weber River Partnership has provided a forum where fisheries managers have told the story of Bonneville Cutthroat Trout and Bluehead Sucker and the importance of habitat connectivity. Through collaborative relationships with nontraditional partners, the relevance of fisheries in the Weber River has been realized. Further relevance in the watershed is evidenced by the development of a wide range of on-the-ground actions. Fish passage has been re-established at three main-stem and four tributary barriers. Additional projects are in various stages of development, including a large fish ladder that will be built as part of a Federal Energy Regulatory Commission relicensing project at a small hydroelectric dam, and we continue to be contacted by water users with interest in developing irrigation diversion reconstruction projects that incorporate fish passage.

Effect of juvenile steelhead (Oncorhynchus mykiss) on age-O and age-1 brown t rout (Salmo trutta) survival and growth in a sympatric nursery stream.

1995 ◽  
Vol 52 (1) ◽  
pp. 105-114 ◽  
Author(s):  
John F. Kocik ◽  
William W. Taylor
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Abiotic Factors ◽  
Substantial Effect ◽  
Lake Huron ◽  
Intraspecific Interactions ◽  
Need To Evaluate ◽  
Brown Trout Salmo Trutta ◽  
Survival And Growth ◽  
Juvenile Brown Trout

We determined that juvenile steelhead (Oncorynchus mykiss) had little effect on the survival and growth of age-0 and age-1 brown trout (Salmo trutta) in a Lake Huron tributary. Starting in 1989, we surveyed wild brown trout juveniles in two stream sections. Unfed steelhead fry were introduced into one section in May of 1990 and 1991, establishing moderate populations. Assessments continued through 1992. Steelhead had no measurable effect on juvenile brown trout abundance or survival. Steelhead did negatively influence age-0 brown trout growth, but this effect was minor compared with intraspecific interactions and abiotic factors. We attribute much of the brown trout success to their larger size. In June sampling, brown trout were typically 42% larger than steelhead, as would be common in the region. Variability in factors such as spawner-alevin interactions or climate could alter the timing of emergence or initial abundance, causing a more substantial effect on growth and, potentially, survival. Fishery managers need to evaluate these factors for the stocks in question before combining these species.

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