Developmental success of hybrids between two taxa of salmonid fishes with moderate structural gene divergence

1988 ◽  
Vol 66 (6) ◽  
pp. 1389-1395 ◽  
Author(s):  
Moira M. Ferguson ◽  
Roy G. Danzmann ◽  
Fred W. Allendorf

The developmental rate and stability of Yellowstone cutthroat trout (Salmo clarki bouvieri) (Y), westslope cutthroat trout (Salmo clarki lewisi) (W), and their hybrids (female × male) were used to examine the evolutionary divergence of gene regulatory systems between these taxa. The Nei's structural gene divergence between these subspecies has been estimated as D = 0.34. Pure W × W developed significantly faster than Y × Y as detected by hatching time and degree of yolk sac resorption. In addition, W × W embryos had greater activities of malate dehydrogenase, lactate dehydrogenase, phosphoglucomutase, and glucose-6-phosphate isomerase from hatching to yolk sac resorption than Y × Y embryos. The two hybrids did not differ significantly from their maternal parental cross in hatching time. W × Y hybrids did, however, hatch significantly sooner than Y × W hybrids. There were no consistent differences between the parental crosses and hybrids in the amount and rate of increase in activity of the four enzymes. Hybrids had significantly greater meristic counts for two out of four characters than the parental crosses. Heterotic effects were observed in that hybrids were longer and showed a faster rate of yolk sac resorption than their maternal parental cross. Moreover, the Y × W hybrid had significantly greater developmental stability as measured by fluctuating asymmetry of four bilateral meristic characters than the Y × Y cross. The lack of perturbation in the development of hybrids indicates that despite their structural gene divergence, few gene regulatory incompatibilities affecting the developmental process exist between these cutthroat trout taxa.

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.


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.


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.


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.


2017 ◽  
Vol 4 (11) ◽  
pp. 171253 ◽  
Author(s):  
Mary M. Peacock ◽  
Evon R. Hekkala ◽  
Veronica S. Kirchoff ◽  
Lisa G. Heki

Currently one small, native population of the culturally and ecologically important Lahontan cutthroat trout ( Oncorhynchus clarkii henshawi , LCT, Federally listed) remains in the Truckee River watershed of northwestern Nevada and northeastern California. The majority of populations in this watershed were extirpated in the 1940s due to invasive species, overharvest, anthropogenic water consumption and changing precipitation regimes. In 1977, a population of cutthroat trout discovered in the Pilot Peak Mountains in the Bonneville basin of Utah, was putatively identified as the extirpated LCT lacustrine lineage native to Pyramid Lake in the Truckee River basin based on morphological and meristic characters. Our phylogenetic and Bayesian genotype clustering analyses of museum specimens collected from the large lakes (1872–1913) and contemporary samples collected from populations throughout the extant range provide evidence in support of a genetically distinct Truckee River basin origin for this population. Analysis of museum samples alone identified three distinct genotype clusters and historical connectivity among water bodies within the Truckee River basin. Baseline data from museum collections indicate that the extant Pilot Peak strain represents a remnant of the extirpated lacustrine lineage. Given the limitations on high-quality data when working with a sparse number of preserved museum samples, we acknowledge that, in the end, this may be a more complicated story. However, the paucity of remnant populations in the Truckee River watershed, in combination with data on the distribution of morphological, meristic and genetic data for Lahontan cutthroat trout, suggests that recovery strategies, particularly in the large lacustrine habitats should consider this lineage as an important part of the genetic legacy of this species.


1966 ◽  
Vol 23 (10) ◽  
pp. 1475-1485 ◽  
Author(s):  
Lawrence A. Jahn

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.


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