Relative Roles of Food Abundance and Cover in Determining the Habitat Distribution of Stream-Dwelling Cutthroat Trout (Salmo clarki)

1985 ◽  
Vol 42 (10) ◽  
pp. 1668-1672 ◽  
Author(s):  
Margaret A. Wilzbach
Keyword(s):  
Cutthroat Trout ◽  
Food Abundance ◽  
High Food ◽  
Habitat Distribution ◽  
Emigration Rate ◽  
Microhabitat Distribution ◽  
Summer Temperatures ◽  
Salmo Clarki

Emigration of wild cutthroat trout (Salmo clarki) from laboratory channels over 1-wk trial periods was greater under conditions of low than high food abundance (5 vs. 15% of total trout biomass daily), irrespective of the amount of cover (simulated cover structures added vs. removed). When food abundance was high, emigration of trout was slightly greater under conditions of low than high cover. Cover had no effect on emigration rate when food abundance was low. Trout occurred in association with cover structures when food abundance was high, but not when food abundance was low. These experiments suggest that at summer temperatures, food abundance overrides cover in determining the abundance and microhabitat distribution of adult cutthroat trout within a stream.

EFFECT OF VARIOUS HORMONES ON THE KIDNEY RESPIRATION RATES IN THE CUTTHROAT TROUT (SALMO CLARKI CLARKI)

1960 ◽  
Vol XXXIII (III) ◽  
pp. 428-436 ◽  
Author(s):  
W. N. Holmes
Keyword(s):  
Single Dose ◽  
Respiration Rate ◽  
Cutthroat Trout ◽  
Adaptive Mechanism ◽  
Respiration Rates ◽  
Salmo Clarki

ABSTRACT Relatively large doses of vasopressin administered intraperitoneally to the trout significantly enhanced the kidney respiration rate. In contrast to vasopressin a single dose of oxytocin depressed the kidney Qo2 value. This depression continued throughout the observed 24 hour period after injection. Cortisol enhanced the kidney Qo2 values significantly and to a greater extent than vasopressin. These results are discussed in relation to possible adaptive mechanism in euryhaline species of teleosts.

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.

INTROGRESSION BETWEEN TWO CUTTHROAT TROUT SUBSPECIES WITH SUBSTANTIAL KARYOTYPIC, NUCLEAR AND MITOCHONDRIAL GENOMIC DIVERGENCE

Genetics ◽  
1985 ◽  
Vol 111 (4) ◽  
pp. 905-915
Author(s):  
Ulf Gyllensten ◽  
Robb F Leary ◽  
Fred W Allendorf ◽  
Allan C Wilson
Keyword(s):  
Random Mating ◽  
Sequence Divergence ◽  
Cutthroat Trout ◽  
Secondary Contact ◽  
Enzyme Analysis ◽  
Restriction Enzyme Analysis ◽  
Hybrid Swarm ◽  
Genetic Barrier ◽  
Allozyme Loci ◽  
Salmo Clarki

ABSTRACT The authors used allozymes encoded by nuclear genes and restriction enzyme analysis of mitochondrial DNA (mtDNA) to study secondary contact between westslope (Salmo clarki lewisi) and Yellowstone cutthroat trout (Salmo clarki bouvieri) in Forest Lake, Montana. Eleven diagnostic allozyme loci identified this as a random-mating hybrid swarm. No parental, first-generation hybrid or backcross genotypes were detected in the sample (N = 33), and genotype distributions at all the variable loci conform to binomial expectations. There is little linkage disequilibrium between the diagnostic loci, indicating that the nuclear genomes of the two subspecies are largely randomly associated. The allozymes and mtDNA give identical estimates of the proportional genetic contribution of each subspecies. Thus, males and females from both subspecies have contributed equally to this hybrid swarm. Although these subspecies have accumulated substantial genetic divergence between their nuclear (Nei's D = 0.34) and mitochondrial (2% sequence divergence) genomes, this has not resulted in a genetic barrier to exchange between them.

Movements of Cutthroat Trout after Different Periods of Retention Upstream and Downstream from their Homes

1954 ◽  
Vol 11 (5) ◽  
pp. 550-558 ◽  
Author(s):  
Richard B. Miller
Keyword(s):  
Rocky Mountains ◽  
Cutthroat Trout ◽  
Experimental Area ◽  
Salmo Clarki ◽  
Homing Experiment ◽  
Home Territory

A homing experiment of cutthroat trout (Salmo clarki) was carried out in Gorge Creek, a small trout stream more or less typical of the streams of the eastern slopes of the Rocky Mountains in Alberta. A half-mile portion of the stream was screened off and, into the enclosure thus formed, 105 trout were transferred from above and 104 from below. Each of these was given a numbered tag and the home locality was recorded. The transfers were made from June 24 to August 13. On August 15 the screens were removed; from September 3 to 5 most of the experimental area was poisoned with Fish Tox and the localities of tagged fish recorded. It was found that most of the trout that had been confined for 30 or more days remained in the enclosure area, i.e., they had adjusted to new homes. The exceptions appear to be the result of random movements. Trout of upstream origin, confined for less than 30 days, move toward their original home territory. Trout of downstream origin, confined for less than 30 days, show very much less ability to move toward or to find their homes. The hypothesis is put forward that trout are guided by smell in finding home.A few observations on size of home territory suggest that it is small, perhaps not more than 20 yards of stream. Trout may inhabit the same area of stream for at least three years.

Open-Water Movements of the Cutthroat Trout (Salmo clarki) in Yellowstone Lake After Displacement from Spawning Streams

1966 ◽  
Vol 23 (10) ◽  
pp. 1475-1485 ◽  
Author(s):  
Lawrence A. Jahn
Keyword(s):  
Cutthroat Trout ◽  
Open Water ◽  
Surface Currents ◽  
The Sun ◽  
Release Point ◽  
Yellowstone Lake ◽  
Random Movement ◽  
Directional Preference ◽  
Salmo Clarki ◽  
Spawning Streams

Cutthroat trout were taken from their spawning streams (June–August 1964 and 1965). A Styrofoam float was attached and fish were tracked from two release points. They moved generally shoreward (eastward). Of 120 fish tracked when the sun was visible, 68% went toward shore, 19% went away from shore, 4% showed random movement, and 8% were lost. Of 20 fish released when the sun was obscured, 30% went toward shore, 30% went away from shore, 30% showed random movement, and 10% were lost. Movement toward the eastern shoreline was less pronounced for fish liberated at a mid-lake release point. No directional preference was shown with respect to surface currents. There was no evidence that specific landmarks were used for orientation, but the sun may have served as a reference point since fish traveled farther and showed a stronger shoreward tendency on sunny days.

scholarly journals A Cytogentic Analysis of Cutthroat Trout in the Grand Teton and Yellowstone National Parks

1978 ◽  
Vol 2 ◽  
pp. 107-111
Author(s):  
Robert Kitchin
Keyword(s):  
National Parks ◽  
Rocky Mountains ◽  
Genetic Basis ◽  
Cutthroat Trout ◽  
Widespread Distribution ◽  
Behavioral Diversity ◽  
Continental Divide ◽  
Salmo Clarki

The cutthroat trout, Salmo clarki, is the trout species native to the Rocky Mountains on both sides of the Continental Divide. The widespread distribution of cutthroat trout in several independent drainages has resulted in the formation of considerable morphological and behavioral diversity both within and between cutthroat trout populations. Behnke has described several different subspecies of Salmo clarki on the basis of their meristic serological characteristics. However, because the genetic basis of these characteristics is unknown, the results of these studies have been inconclusive for the taxonomic designations of cutthroat trout subspecies in Grand Teton and Yellowstone National Parks.

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