Analysis of trade-offs between threats of invasion by nonnative brook trout (Salvelinus fontinalis) and intentional isolation for native westslope cutthroat trout (Oncorhynchus clarkii lewisi)

2008 ◽  
Vol 65 (4) ◽  
pp. 557-573 ◽  
Author(s):  
Douglas P Peterson ◽  
Bruce E Rieman ◽  
Jason B Dunham ◽  
Kurt D Fausch ◽  
Michael K Young
Keyword(s):  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Cutthroat Trout ◽  
Westslope Cutthroat Trout ◽  
Stream Network ◽  
Systematic Analysis ◽  
Oncorhynchus Clarkii ◽  
Management Actions ◽  
Trade Offs ◽  
Conservation Actions

Native salmonid fishes often face simultaneous threats from habitat fragmentation and invasion by nonnative trout species. Unfortunately, management actions to address one may create or exacerbate the other. A consistent decision process would include a systematic analysis of when and where intentional use or removal of barriers is the most appropriate action. We developed a Bayesian belief network as a tool for such analyses. We focused on native westslope cutthroat trout (Oncorhynchus clarkii lewisi) and nonnative brook trout (Salvelinus fontinalis) and considered the environmental factors influencing both species, their potential interactions, and the effects of isolation on the persistence of local cutthroat trout populations. The trade-offs between isolation and invasion were strongly influenced by size and habitat quality of the stream network to be isolated and existing demographic linkages within and among populations. An application of the model in several sites in western Montana (USA) showed the process could help clarify management objectives and options and prioritize conservation actions among streams. The approach can also facilitate communication among parties concerned with native salmonids, nonnative fish invasions, barriers and intentional isolation, and management of the associated habitats and populations.

Metabolic performance and thermal preference of Westslope Cutthroat Trout Oncorhynchus clarkii lewisi and non-native trout across an ecologically relevant range of temperatures

2021 ◽  
Author(s):  
Camille J. Macnaughton ◽  
Travis C. Durhack ◽  
Neil J. Mochnacz ◽  
Eva C. Enders
Keyword(s):  
Brook Trout ◽  
Cold Water ◽  
Cutthroat Trout ◽  
Intermittent Flow ◽  
Performance Curve ◽  
Westslope Cutthroat Trout ◽  
Oncorhynchus Clarkii ◽  
Thermal Niche ◽  
Preferred Temperatures ◽  
Metabolic Performance

The physiology and behaviour of fish are strongly affected by ambient water temperature. Physiological traits related to metabolism, such as aerobic scope (AS), can be measured across temperature gradients and the resulting performance curve reflects the thermal niche that fish can occupy. We measured AS of Westslope Cutthroat Trout (Oncorhynchus clarkii lewisi) at 5, 10, 15, 20, and 22°C and compared temperature preference (Tpref) of the species to non-native Brook Trout, Brown Trout, and Rainbow Trout. Intermittent-flow respirometry experiments demonstrated that metabolic performance of Westslope Cutthroat Trout was optimal at ~15 °C and decreased substantially beyond this temperature, until lethal temperatures at ~25 °C. Adjusted preferred temperatures across species (Tpref) were comparatively high, ranging from 17.8-19.9 °C, with the highest Tpref observed for Westslope Cutthroat Trout. Results suggest that although Westslope Cutthroat Trout is considered a cold-water species, they do not prefer or perform as well in cold water (≤ 10°C), thus, can occupy a warmer thermal niche than previously thought. The metabolic performance curve (AS) can be used to develop species‐specific thermal criteria to delineate important thermal habitats and guide conservation and recovery actions for Westslope Cutthroat Trout.

Food Specialization By Individual Trout

1972 ◽  
Vol 29 (11) ◽  
pp. 1615-1624 ◽  
Author(s):  
James E. Bryan ◽  
P. A. Larkin
Keyword(s):  
Rainbow Trout ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Stomach Contents ◽  
Cutthroat Trout ◽  
Salmo Gairdneri ◽  
Potential Prey ◽  
Repeated Observation ◽  
Size Growth ◽  
Salmo Clarki

Analyses of stomach contents showed that the kinds of prey eaten by brook trout (Salvelinus fontinalis), cutthroat trout (Salmo clarki), and rainbow trout (Salmo gairdneri) were seldom distributed at random among the individuals. Repeated observation of food eaten by individuals in a stream and ponds showed that prey types were eaten in proportions which were characteristic for an individual.Specialization occurred on several different kinds of prey. Although the degree of specialization was higher during shorter intervals, the data suggested that some specialization persisted for half a year. There were no striking correlations between degree of specialization and other individual properties such as size, growth rate, weight of food, number of food items, previous specialization, or area of recapture.In addition to the observations on trout in relatively undisturbed habitats, a field experiment was conducted using laboratory-reared rainbow trout held in small ponds. The food of each trout in the experiment was sampled repeatedly. In analysis of variance, interaction among the individuals and kinds of prey eaten showed that food specialization occurred. Both the absolute and relative abundance of potential prey were constant during the experiment.

Cutthroat Trout: Evolutionary Biology and Taxonomy

2018 ◽  
Keyword(s):  
Evolutionary Biology ◽  
Cutthroat Trout ◽  
Westslope Cutthroat Trout ◽  
Oncorhynchus Clarkii ◽  
Coastal Cutthroat Trout ◽  
Lahontan Cutthroat Trout ◽  
Museum Samples ◽  
Yellowstone Cutthroat Trout ◽  
The 1960S

<em>Abstract</em>.—There has been considerable interest in the systematics and classification of Cutthroat Trout since the 1800s. Cutthroat Trout native to western North America (currently classified as <em>Oncorhynchus clarkii</em>) have historically been grouped or separated using many different classification schemes. Since the 1960s, Robert Behnke has been a leader in these efforts. Introductions of nonnative trout (other forms of Cutthroat Trout, and Rainbow Trout <em>O. mykiss</em>) have obscured some historical patterns of distribution and differentiation. Morphological and meristic analyses have often grouped the various forms of Cutthroat Trout together based on the shared presence of the “cutthroat mark,” high scale counts along the lateral line, and the presence of basibranchial teeth. Spotting patterns and counts of gill rakers and pyloric caeca have in some cases been helpful in differentiation of groups (e.g., Coastal Cutthroat Trout <em>O. c. clarkii</em>, Lahontan Cutthroat Trout <em>O. c. henshawi</em>, and Westslope Cutthroat Trout <em>O. c. lewisi</em>) currently classified as subspecies. The historical genetic methods of allozyme genotyping through protein electrophoresis and chromosome analyses were often helpful in differentiating the various subspecies of Cutthroat Trout. Allozyme genotyping allowed four major groups to be readily recognized (Coastal Cutthroat Trout, Westslope Cutthroat Trout, the Lahontan Cutthroat Trout subspecies complex, and Yellowstone Cutthroat Trout <em>O. c. bouvieri </em>subspecies complex) while chromosome analyses showed similarity between the Lahontan and Yellowstone Cutthroat trout subspecies complex trout (possibly reflecting shared ancestral type) and differentiated the Coastal and Westslope Cutthroat trouts from each other and those two groups. DNA results may yield higher resolution of evolutionary relationships of Cutthroat Trout and allow incorporation of ancient museum samples. Accurate resolution of taxonomic differences among various Cutthroat Trout lineages, and hybridization assessments, requires several approaches and will aid in conservation of these charismatic and increasingly rare native fishes.

Spatial and temporal spawning dynamics of native westslope cutthroat trout, Oncorhynchus clarkii lewisi, introduced rainbow trout, Oncorhynchus mykiss, and their hybrids

2009 ◽  
Vol 66 (7) ◽  
pp. 1153-1168 ◽  
Author(s):  
Clint C. Muhlfeld ◽  
Thomas E. McMahon ◽  
Durae Belcer ◽  
Jeffrey L. Kershner
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Cutthroat Trout ◽  
River System ◽  
Westslope Cutthroat Trout ◽  
Time And Space ◽  
Long Distance ◽  
Oncorhynchus Clarkii ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Spring Runoff

We used radiotelemetry to assess spatial and temporal spawning distributions of native westslope cutthroat trout ( Oncorhynchus clarkii lewisi ; WCT), introduced rainbow trout ( Oncorhynchus mykiss ; RBT), and their hybrids in the upper Flathead River system, Montana (USA) and British Columbia (Canada), from 2000 to 2007. Radio-tagged trout (N = 125) moved upriver towards spawning sites as flows increased during spring runoff and spawned in 29 tributaries. WCT migrated greater distances and spawned in headwater streams during peak flows and as flows declined, whereas RBT and RBT hybrids (backcrosses to RBT) spawned earlier during increasing flows and lower in the system. WCT hybrids (backcrosses to WCT) spawned intermediately in time and space to WCT and RBT and RBT hybrids. Both hybrid groups and RBT, however, spawned over time periods that produced temporal overlap with spawning WCT in most years. Our data indicate that hybridization is spreading via long-distance movements of individuals with high amounts of RBT admixture into WCT streams and stepping-stone invasion at small scales by later generation backcrosses. This study provides evidence that hybridization increases the likelihood of reproductive overlap in time and space, promoting extinction by introgression, and that the spread of hybridization is likely to continue if hybrid source populations are not reduced or eliminated.

Genetic variation in westslope cutthroat trout Oncorhynchus clarkii lewisi: implications for conservation

2011 ◽  
Vol 12 (6) ◽  
pp. 1513-1523 ◽  
Author(s):  
Daniel P. Drinan ◽  
Steven T. Kalinowski ◽  
Ninh V. Vu ◽  
Bradley B. Shepard ◽  
Clint C. Muhlfeld ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Cutthroat Trout ◽  
Westslope Cutthroat Trout ◽  
Oncorhynchus Clarkii

Cold tolerance performance of westslope cutthroat trout (Oncorhynchus clarkii lewisi) and rainbow trout (Oncorhynchus mykiss) and its potential role in influencing interspecific hybridization

2014 ◽  
Vol 92 (9) ◽  
pp. 777-784 ◽  
Author(s):  
M.M. Yau ◽  
E.B. Taylor
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Water Temperature ◽  
Cold Water ◽  
Cutthroat Trout ◽  
Acclimation Temperature ◽  
Westslope Cutthroat Trout ◽  
Oncorhynchus Clarkii ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Differential Adaptation

Hybridization between rainbow trout (Oncorhynchus mykiss (Walbaum, 1792)) and westslope cutthroat trout (Oncorhynchus clarkii lewisi (Girard, 1856)) occurs commonly when rainbow trout are introduced into the range of westslope cutthroat trout. Typically, hybridization is most common in warmer, lower elevation habitats, but much less common in colder, higher elevation habitats. We assessed the tolerance to cold water temperature (i.e., critical thermal minimum, CTMin) in juvenile rainbow trout and westslope cutthroat trout to test the hypothesis that westslope cutthroat trout better tolerate low water temperature, which may explain the lower prevalence of rainbow trout and interspecific hybrids in higher elevation, cold-water habitats (i.e., the “elevation refuge hypothesis”). All fish had significantly lower CTMin values (i.e., were better able to tolerate low temperatures) when they were acclimated to 15 °C (mean CTMin = 1.37 °C) versus 18 °C (mean CTMin = 1.91 °C; p < 0.001). Westslope cutthroat trout tended to have lower CTMin than rainbow trout from two populations, second–generation (F2) hybrids between two rainbow trout populations, and backcrossed rainbow trout at 15 °C (cross type × acclimation temperature interaction; p = 0.018). Differential adaptation to cold water temperatures may play a role in influencing the spatial distribution of hybridization between sympatric species of trout.

scholarly journals Estimating westslope cutthroat trout (Oncorhynchus clarkii lewisi) movements in a river network using strontium isoscapes

2012 ◽  
Vol 69 (5) ◽  
pp. 906-915 ◽  
Author(s):  
Clint C. Muhlfeld ◽  
Simon R. Thorrold ◽  
Thomas E. McMahon ◽  
Brian Marotz
Keyword(s):  
Life History ◽  
Isotope Composition ◽  
Cutthroat Trout ◽  
Large River ◽  
River Network ◽  
Life History Strategies ◽  
Westslope Cutthroat Trout ◽  
Oncorhynchus Clarkii ◽  
Spatial Differences ◽  
Highly Correlated

We used natural variation in the strontium concentration (Sr:Ca) and isotope composition (87Sr:86Sr) of stream waters and corresponding values recorded in otoliths of westslope cutthroat trout ( Oncorhynchus clarkii lewisi ) to examine movements during their life history in a large river network. We found significant spatial differences in Sr:Ca and 87Sr:86Sr values (strontium isoscapes) within and among numerous spawning and rearing streams that remained relatively constant seasonally. Both Sr:Ca and 87Sr:86Sr values in the otoliths of juveniles collected from nine natal streams were highly correlated with those values in the ambient water. Strontium isoscapes measured along the axis of otolith growth revealed that almost half of the juveniles had moved at least some distance from their natal streams. Finally, otolith Sr profiles from three spawning adults confirmed homing to natal streams and use of nonoverlapping habitats over their migratory lifetimes. Our study demonstrates that otolith geochemistry records movements of cutthroat trout through Sr isoscapes and therefore provides a method that complements and extends the utility of conventional tagging techniques in understanding life history strategies and conservation needs of freshwater fishes in river networks.

Comparative Behavior and Habitat Utilization of Brook Trout (Salvelinus fontinalis) and Cutthroat Trout (Salmo clarki) in Small Streams in Northern Idaho

1972 ◽  
Vol 29 (3) ◽  
pp. 265-273 ◽  
Author(s):  
J. S. Griffith Jr.
Keyword(s):  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Age Groups ◽  
Cutthroat Trout ◽  
Habitat Characteristics ◽  
Stream Channels ◽  
Sympatric Populations ◽  
Small Streams ◽  
Northern Idaho ◽  
Salmo Clarki

Individual brook (Salvelinus fontinalis) and cutthroat (Salmo clarki) trout communicated with similar behavioral signals, both in laboratory stream-channels and in northern Idaho streams. Underyearling brook trout were less active socially than equal-sized cutthroat trout in laboratory observations. In study streams, brook trout maintained a 20-mm size advantage over cutthroat of the same age-groups throughout their lives, as they emerged from the gravel before cutthroat. Because of this size advantage, underyearling brook trout of sizes found in study streams in September consistently dominated in experiments the underyearling cutthroat with which they normally lived. But in study streams underyearlings of the two species utilized different microhabitats, particularly with respect to water depth, and so minimized chances for interaction.Yearling and older brook trout initiated 40% fewer aggressive encounters under laboratory conditions than did equal-sized cutthroat trout, and did not displace the cutthroat. In study streams with sympatric populations, cutthroat trout of these age-groups occupied territories with focal points of higher water velocities (averaging 10.2–10.3 cm/sec) than those occupied by brook trout (averaging 7.6–9.6 cm/sec). Considerable interspecific overlap in other habitat characteristics occurred for trout of age-groups I and II. The oldest members of the two species segregated more distinctly, as the brook trout lived closer to overhead cover.

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