Segregation of resident trout in streams as predicted by three habitat dimensions

1992 ◽  
Vol 70 (5) ◽  
pp. 886-890 ◽  
Author(s):  
Michael A. Bozek ◽  
Wayne A. Hubert
Keyword(s):  
Rainbow Trout ◽  
Brown Trout ◽  
Rocky Mountains ◽  
Brook Trout ◽  
Elevation Gradient ◽  
Cutthroat Trout ◽  
Individual Species ◽  
Habitat Features ◽  
Central Rocky Mountains ◽  
Habitat Variables

We assessed the relation of three measures of habitat to the distribution of four species of Salmonidae, cutthroat trout (Oncorhynchus clarki), brook trout (Salvelinus fontinalis), brown trout (Salmo trutta), and rainbow trout (Oncorhynchus mykiss), in streams of the central Rocky Mountains. We examined whether single measures of three habitat dimensions (climate, stream energy, and stream size) could account for current distribution patterns of four resident trout species in Wyoming. The three habitat dimensions were represented by three habitat variables: elevation, channel gradient, and wetted stream width. Considerable overlap in the ranges of elevation, gradient, and wetted width was observed among reaches where the four species were found, but differences in the mean values of these habitat features were observed among species. Using discriminant analysis, we categorized the presence and absence of individual species in stream reaches by the three habitat variables. We successfully predicted the presence of brook trout (87%), cutthroat trout (59%), brown trout (50%), and rainbow trout (39%) in streams, but the absence of each species was predicted more successfully (rainbow trout (94%), brown trout (94%), cutthroat trout (90%), and brook trout (57%)). The three habitat features were useful in describing the segregation of trout species in streams of the central Rocky Mountains.

Changes in the visual pigments of trout

1973 ◽  
Vol 51 (9) ◽  
pp. 901-914 ◽  
Author(s):  
Donald M. Allen ◽  
William N. McFarland ◽  
Frederick W. Munz ◽  
Hugh A. Poston
Keyword(s):  
Rainbow Trout ◽  
Brown Trout ◽  
Visual Pigment ◽  
Brook Trout ◽  
Forest Canopy ◽  
Environmental Control ◽  
Cutthroat Trout ◽  
Visual Pigments ◽  
Salmo Gairdneri ◽  
Canopy Access

The proportions of two visual pigments (rhodopsin and porphyropsin) were examined in four species of trout under experimental and natural conditions. Brook trout (Salvelinus fontinalis), rainbow trout (Salmo gairdneri), and brown trout (Salmo trutta) have different relative proportions of visual pigments in their retinae. The visual pigment balance in wild cutthroat trout (Salmo clarki) is related to forest canopy (access to light) and season. The brown trout have a more red-sensitive and less labile pair of visual pigments than brook or rainbow trout, which respond to photic conditions by increasing the proportion of porphyropsin (in light) and increasing rhodopsin (in darkness). The brown trout have a high percentage of porphyropsin, regardless of experimental conditions. This result does not reflect an inability to form rhodopsin but rather may relate to a consistently high proportion of 3-dehydroretinol in the pigment epithelium. The possible advantages and mechanisms of environmental control of trout visual pigment absorbance, as currently understood, are discussed.

Trends in the Distribution and Abundance of Yellowstone Cutthroat Trout and Nonnative Trout in Idaho

2014 ◽  
Vol 5 (2) ◽  
pp. 227-242 ◽  
Author(s):  
Kevin A. Meyer ◽  
Erin I. Larson ◽  
Christopher L. Sullivan ◽  
Brett High
Keyword(s):  
Rainbow Trout ◽  
River Basin ◽  
Brown Trout ◽  
Brook Trout ◽  
Salmo Trutta ◽  
Cutthroat Trout ◽  
Snake River ◽  
Trout Population ◽  
Yellowstone Cutthroat Trout ◽  
Over Time

Abstract The distribution and abundance of Yellowstone cutthroat trout Oncorhynchus clarkii bouvieri across their native range is relatively well-known, but evaluations of trends in distribution and abundance over time are lacking. In 2010–2011, we resurveyed 74 stream reaches in the upper Snake River basin of Idaho that were sampled in the 1980s and again in 1999–2000 to evaluate changes in the distribution and abundance of Yellowstone cutthroat trout and nonnative trout over time. Yellowstone cutthroat trout occupied all 74 reaches in the 1980s, 70 reaches in 1999–2000, and 69 reaches in 2010–2011. In comparison, rainbow trout O. mykiss and rainbow × cutthroat hybrid occupancy increased from 23 reaches in the 1980s to 36 reaches in 1999–2000, and then declined back to 23 reaches in 2010–2011. The proportion of reaches occupied by brown trout Salmo trutta and brook trout Salvelinus fontinalis was largely unchanged across time periods. Yellowstone cutthroat trout abundance declined from a mean of 40.0 fish/100 linear meters of stream in the 1980s to 32.8 fish/100 m in 2010–2011. In contrast, estimates of abundance increased over time for all species of nonnative trout. Population growth rate (λ) was therefore below replacement for Yellowstone cutthroat trout (mean  =  0.98) and above replacement for rainbow trout (1.07), brown trout (1.08), and brook trout (1.04), but 90% confidence intervals overlapped unity for all species. However, λ differed statistically from 1.00 within some individual drainages for each species. More pronounced drought conditions in any given year resulted in lower Yellowstone cutthroat trout abundance 1 y later. Our results suggest that over a span of up to 32 y, the distribution and abundance of Yellowstone cutthroat trout in the upper Snake River basin of Idaho appears to be relatively stable, and nonnative trout do not currently appear to be expanding across the basin.

Landscape Influences on Stream Habitats and Biological Assemblages

2006 ◽  
Keyword(s):  
Rainbow Trout ◽  
Brown Trout ◽  
Brook Trout ◽  
Coho Salmon ◽  
Base Flow ◽  
Flow Index ◽  
Great Lakes Basin ◽  
Habitat Features ◽  
Base Flow Index ◽  
Local Habitat

<em>Abstract.</em>—Effective management of salmonid populations in the Great Lakes basin requires understanding how their distribution and density vary spatially. We used a hierarchical approach to evaluate the predictive capabilities of landscape conditions, local habitat features, and potential effects from coinhabiting salmonids on the distribution and densities of rainbow trout <em>Oncorhynchus mykiss</em>, brook trout <em>Salvelinus fontinalis, </em>brown trout <em>Salmo trutta</em>, and coho salmon <em>O. kisutch </em>within the majority of the Canadian tributaries of Lake Ontario. We collected fish assemblage, instream habitat, and water temperature data from 416 wadeable stream sites. Landscape characteristics were obtained for each site’s catchment and summarized into six key attributes (drainage area, base flow index, percent impervious cover (PIC), reach slope, elevation, and location with respect to permanent fish barriers). Classification trees indicated that PIC in a catchment was a critical predictor of salmonid distribution, in that beyond a threshold of 6.6–9 PIC, all salmonids were predicted to be absent. Base flow index and barriers were also important predictors of the distribution of salmonids. Models generally provided higher classification success at predicting absence (86–98%) than predicting presence (63–87%). Landscape features were the best predictors of densities of rainbow and brook trout (adjusted <em>r</em><sup>2</sup> = 0.49 and 0.30 respectively), although the local habitat features were almost as effective for predicting brook trout (<em>r</em><sup>2</sup> = 0.23). Local habitat features (proportion of riffles and pools, substrate, cover, and stream temperature), and presence of other salmonids produced the best predictive model for brown trout. Coho salmon was only locally distributed in the basin, and the derived model was driven by spatial characteristics rather than ecological processes. Our models estimate 653,000 juvenile rainbow trout and 231,000 brook trout (all age-classes) in our study streams. Finally, we estimate that current brook trout distribution in our study area is only 21% of its historic range.

Effects of Fish Introductions and Hydroelectric Development on Fishes in the Kananaskis River System, Alberta

1965 ◽  
Vol 22 (3) ◽  
pp. 721-753 ◽  
Author(s):  
J. S. Nelson
Keyword(s):  
Rainbow Trout ◽  
Brown Trout ◽  
Brook Trout ◽  
Salmo Trutta ◽  
Cutthroat Trout ◽  
River System ◽  
Hydroelectric Development ◽  
Fish Introductions ◽  
Longnose Suckers ◽  
Abundance And Distribution

Changes occurred in the abundance and distribution of fishes in the Kananaskis River system, Alberta, in conjunction with fish introductions and hydroelectric development. Data from surveys from 1936 to 1961 indicate the probable chronology of events.Dolly Varden (Salvelinus malma), brook trout (S. fontinalis), cutthroat trout (Salmo clarkii), and rainbow trout (S. gairdneri) decreased in abundance, probably due to the introduction of brown trout (Salmo trutta), longnose suckers (Catostomus catostomus), and white suckers (C. commersonii), to the cooling of the Kananaskis River from reservoir construction, and to sport fishing. Hybridization between rainbow and cutthroat trout was also important in the decrease of the latter species. After introduction by man, brown trout, rainbow trout, longnose suckers, white suckers, lake chub (Hybopsis plumbea), and longnose dace (Rhinichthys cataractae) greatly increased in abundance. Prior to the increase in numbers of white suckers, a reduction in the numbers of longnose suckers occurred in Lower Kananaskis Reservoir. Little change in the distribution of mountain whitefish (Prosopium williamsoni), longnose dace, and brook sticklebacks (Culaea (= Eucalia) inconstans) occurred over the 25 years. Changes in the physicochemical environment and invertebrate fauna in the reservoirs appeared to be of secondary importance to the interaction among fish in causing the changes in species abundance and distribution.

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):  
Rainbow Trout ◽  
Rocky Mountains ◽  
Evolutionary Biology ◽  
Cutthroat Trout ◽  
Taxonomic Revision ◽  
River Basins ◽  
Evidence Based ◽  
Oncorhynchus Clarkii ◽  
Southern Rocky Mountains ◽  
Green Lineage

<em>Abstract</em>.—One objective of systematics is to recognize species in a manner that minimizes the disparity between species as real entities in nature and species as a Linnaean category. Reconciliation requires a conceptualization of species consistent with evolutionary processes that yields predictive delimitation criteria. Here we review the unified species concept (USC) and its associated delimitation criteria as a prelude to revising the taxonomy of Cutthroat Trout <em>Oncorhynchus clarkii</em>. Additionally, in the context of the conceptualizing species as a separately evolving metapopulation, we briefly review how climate change may have influenced the connectivity and isolation of Cutthroat Trout within and among river basins, with a focus mainly on the Cutthroat Trout of the Southern Rocky Mountains. We summarize evidence based on delimitation criteria that distinguishes Rainbow Trout <em>O. mykiss</em> and Cutthroat Trout, Gila Trout<em> O. gilae </em>and Rainbow Trout, and blue lineage and green lineage Cutthroat Trout from the Southern Rocky Mountains. We advocate adopting the USC as a guide for taxonomic revision of Cutthroat Trout, recommend eliminating subspecies as a valid taxonomic designation, and expect—based on our evaluation of three pairs of species—that the taxonomy of Cutthroat Trout will be revised in ways that elevate some recognized subspecies to species status.

Bacterial Kidney Disease in Feral Populations of Brook Trout (Salvelinus fontinalis), Brown Trout (Salmo trutta), and Rainbow Trout (Salmo gairdneri)

1979 ◽  
Vol 36 (11) ◽  
pp. 1370-1376 ◽  
Author(s):  
Douglas L. Mitchum ◽  
Loris E. Sherman ◽  
George T. Baxter
Keyword(s):  
Rainbow Trout ◽  
Kidney Disease ◽  
Brown Trout ◽  
Brook Trout ◽  
Salmo Trutta ◽  
Salmo Gairdneri ◽  
Age Classes ◽  
Bacterial Kidney Disease ◽  
Live Fish ◽  
Brown Trout Salmo Trutta

Incidence and effects of bacterial kidney disease (BKD) were determined in wild, naturally reproducing populations of brook trout (Salvelinus fontinalis), brown trout (Salmo trutta), and rainbow trout (Salmo gairdneri) in a small lake and stream system in southeastern Wyoming, USA where BKD epizootics have been observed since 1972. During 1976, dead fish were collected at three upstream stations, and 60 live fish were collected from each of 11 stations. All fish were necropsied, and virological, bacteriological, and parasitological examinations were conducted by standard methods. An indirect fluorescent antibody technique was used to detect the BKD organism in cultures and kidney tissue smears. Bacterial kidney disease was diagnosed in 100% of the dead brook trout collected. Incidence among live fish ranged from 83% at an upstream station to only 3% at the most downstream location, and was highest in brook trout and lowest in rainbow trout. Two longnose suckers (Catostomus catostomus), the only non-salmonids collected, were found negative for BKD. Clinical signs of infection and the most severe infections were found only in brook trout. Five age-classes of feral brook trout were involved in the epizootics. Since other known pathogens were essentially absent, it is believed that all deaths were due to BKD. Relationships between species susceptibility to BKD, age-classes, water chemistry and water temperatures, and certain ecological conditions are discussed. Key words: bacterial kidney disease, feral trout, epizootics, brook trout, brown trout, rainbow trout

scholarly journals Study and development of methods for obtaining intergeneric hybrids of salmonids (Salmonidae (Jarocki or Schinz, 1822)) for achieving the effect of heterosis and increasing their productivity

2021 ◽  
pp. 40-55
Author(s):  
A. Mruk ◽  
◽  
G. Kucheruk ◽  
L. Galoyan ◽  
N. Mykhailenko ◽  
...  
Keyword(s):  
Body Weight ◽  
Rainbow Trout ◽  
Brown Trout ◽  
Brook Trout ◽  
Intergeneric Hybrids ◽  
Average Weight ◽  
Young Of The Year ◽  
Average Body Length ◽  
Average Body ◽  
Average Body Weight

Purpose. To study the possibility of obtaining highly productive intergeneric salmonid hybrids between rainbow trout and brook trout; brown trout and brook trout; rainbow trout and brown trout, as well as to develop methodological approaches and determine of optimal variants of hybrid crosses. Findings. In order to obtain intergeneric hybrids, we used six variants of hybrid crosses with brood fish of three salmonids belonging to three families (Salmo, Oncorhynhus, Salvelinus). The study used age-4 female rainbow trout with average body weight of 3296.8 g, Fork length was 62.6 cm, and the average working fecundity was 7420 eggs. Age-3 rainbow trout males had an average body weight of 1613 g and an average body length of 49.8 cm; age-3 brown trout females had an average body weight of 453.8 g and average working fecundity of 1540 eggs, and males had an average weight of 458.7 g; age-3 brook trout females had an average weight of 809.7 g and a length of 38.9 cm with working fecundity of 1732 eggs, and age-4 males had an average weight of 1212.8 g and an average body length of 46.0 cm. Twelve variants of fertilization were used: six variants at normal water temperature and six variants after a temperature shock. Under natural conditions, the creation of intergeneric hybrids is almost impossible, except for variants between brown trout and brook trout, which is due to the similarity of their biology. However, the efficiency of this cross is low and economically impractical for fish farmers. When applying the temperature shock during fertilization, hybrids proved to be the most effective, where females were rainbow trout, and males were brook trout and brown trout. The average weight of young-of-the-year intergeneric hybrids was, depending on the species of fish, from 8 to 54 g. The highest results were obtained for the creation of hybrids where following broodstock was used: ♂brook trout Х ♀brown trout; ♂brown trout Х ♀rainbow trout. In these variants of crossbreeding, the survival rate of young-of-the-year during the period of cultivation was 94.8 and 92.8%, respectively. In particular, the above hybrids did not suffer from infectious diseases during the growing period. Originality. New data on the development of methods for obtaining viable offspring of newly created hybrids were obtained, and the optimal variants of crossing between females and males of these salmonids were determined. Practical value. The results can be used for artificial breeding of salmonids in specialized farms that will allow obtaining high quality products and reducing their costs. Key words:rainbow trout, brown trout, brook trout, incubation, free embryos, larvae, fry, young-of-the-year.

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