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

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.

Author(s):  
Robert Kitchin

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.


1957 ◽  
Vol 14 (5) ◽  
pp. 687-691 ◽  
Author(s):  
Richard B. Miller

Gorge Creek is a small cutthroat trout stream in Alberta on the eastern slopes of the Rocky Mountains. In the summer of 1954, 98 trout were tagged with Petersen tags, weighed and returned to the pool of capture. In the same summer and in the next two, 58 of these trout were recaptured, some several times, so that, altogether, 83 records were obtained. Twenty-three records are of the first year, 35 from the second and 25 from the third.Sixty-seven per cent of the recaptures were made in the original pool or less than 200 yards from it. Of the remaining 33%, one fish had moved 1.5 miles upstream and remained there. The others had all drifted downstream. The drifters were smaller fish than those that stayed home, and they either lost weight or gained at rates considerably below normal. It is suggested these fish had been injured by the tags. The general conclusion is that each cutthroat trout of Gorge Creek has a home territory not over twenty yards long and that the whole life is spent in it.


1960 ◽  
Vol XXXIII (III) ◽  
pp. 428-436 ◽  
Author(s):  
W. N. Holmes

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.


1972 ◽  
Vol 29 (11) ◽  
pp. 1615-1624 ◽  
Author(s):  
James E. Bryan ◽  
P. A. Larkin

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.


<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.


Genetics ◽  
1985 ◽  
Vol 111 (4) ◽  
pp. 905-915
Author(s):  
Ulf Gyllensten ◽  
Robb F Leary ◽  
Fred W Allendorf ◽  
Allan C Wilson

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.


1985 ◽  
Vol 42 (10) ◽  
pp. 1668-1672 ◽  
Author(s):  
Margaret A. Wilzbach

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.


Sign in / Sign up

Export Citation Format

Share Document