Electrophoretic Distinction of Rainbow Trout (Salmo gairdneri), West-Slope Cutthroat Trout (S. clarki), and Their Hybrids

1977 ◽  
Vol 34 (8) ◽  
pp. 1236-1239 ◽  
Author(s):  
Gary L. Reinitz
Keyword(s):  
Rainbow Trout ◽  
Key Words ◽  
Biochemical Marker ◽  
Cutthroat Trout ◽  
Phosphoglucose Isomerase ◽  
Western Montana ◽  
Salmo Gairdneri ◽  
Native Populations ◽  
Salmo Clarki

Rainbow trout (Salmo gairdneri), west-slope cutthroat trout (Salmo clarki), and their F1 hybrids were electrophoretically examined for 13 different proteins. Of the 13 proteins, only phosphoglucose isomerase (PGI) proved to be a reliable biochemical marker for the distinction of genetically pure samples of the two species. Only PGI provided an accurate means of identifying F1 hybrids between the species. This information could possibly be used to facilitate the stabilization and restoration of native populations of west-slope cutthroat trout in western Montana. Key words: rainbow trout, west-slope cutthroat trout, hybridization, electrophoresis, biochemical marker, phosphoglucose isomerase (PGI)

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.

scholarly journals Hybridization between Cutthroat and Rainbow Trout: Evidence from Biochemical Genetic Loci

1979 ◽  
Vol 3 ◽  
pp. 108-112
Author(s):  
Eric Loudenslager ◽  
G. Gall
Keyword(s):  
Rainbow Trout ◽  
Related Species ◽  
Cutthroat Trout ◽  
Salmo Gairdneri ◽  
Genetic Loci ◽  
Species Identity ◽  
Closely Related Species ◽  
Isolating Mechanisms ◽  
Biochemical Genetic ◽  
Salmo Clarki

Cutthroat, Salmo clarki, and rainbow, Salmo gairdneri, trout are largely allopatric, closely related species. Where naturally sympatric ecological isolating mechanisms maintain species identity. However, the inland subspecies of cutthroat trout which did not evolve in sympatry with rainbows are thought to freely hybridize with rainbow trout which have been introduced for recreational purposes. Because of the mass introductions of rainbow trout fish managers have become increasingly concerned about the purity of the dwindling stocks of native cutthroats.

Introgressive Hybridization in Populations of Paiute Cutthroat Trout (Salmo clarki seleniris)

1981 ◽  
Vol 38 (8) ◽  
pp. 939-951 ◽  
Author(s):  
Craig A. Busack ◽  
G. A. E. Gall
Keyword(s):  
Population Structure ◽  
Rainbow Trout ◽  
Introgressive Hybridization ◽  
Cutthroat Trout ◽  
The Other ◽  
Salmo Gairdneri ◽  
Electrophoretic Data ◽  
The Difference ◽  
Salmo Clarki ◽  
Two Populations

Two populations of Paiute cutthroat trout (Salmo clarki seleniris) were compared meristically and electrophoretically with Lahontan cutthroat (S. c. henshawi) and rainbow trout (S. gairdneri) to elucidate population structure and verify the occurrence of introgressive hybridization. In Silver King Creek, both meristic and electrophoretic evidence indicated two populations were present, one appearing to be pure Paiute cutthroat, the other Paiute cutthroat introgressed with rainbow trout. Lahontan cutthroat introgression was a possibility in Silver King Creek but could not be evaluated because of the strong meristic and electrophoretic similarity of Paiute and Lahontan cutthroat. The other Paiute population, Cottonwood Creek, meristically appeared to be pure Paiute cutthroat but electrophoretic data indicated it was introgressed with rainbow trout. The existence of the two Silver King Creek populations indicated introgression was incomplete in that stream; introgression appeared to be complete in Cottonwood Creek. The meristic similarity of Cottonwood Creek trout to pure Paiute cutthroat was probably a result of strong selection by management agencies for a Paiute cutthroat phenotype. Electrophoresis was more discriminating than meristic analysis in this study in detecting introgression. Electrophoresis also allowed more detailed analysis of population structure than meristics because of the difference in complexity of the genetic systems analyzed by the two techniques. However, the application of both techniques contributed greatly to our understanding of introgression in the Paiute cutthroat and demonstrated the complementarity of the two approaches.Key words: Salmo clarki, Salmo gairdneri, Paiute cutthroat, Lahontan cutthroat, meristics, electrophoresis, introgression, hybridization, gametic disequilibrium, principal components

Swimming Stamina Differences Between Genotypically Distinct Forms of Rainbow (Salmo gairdneri) and Steelhead Trout

1977 ◽  
Vol 34 (7) ◽  
pp. 996-1003 ◽  
Author(s):  
H. Tsuyuki ◽  
S. N. Williscroft
Keyword(s):  
Rainbow Trout ◽  
Lactate Dehydrogenase ◽  
Key Words ◽  
Low Frequency ◽  
Water Velocity ◽  
Salmo Gairdneri ◽  
Steelhead Trout ◽  
Very Low Frequency ◽  
Time Required

Rainbow trout (Salmo gairdneri) homozygous for liver lactate dehydrogenase alleles ldhHαA and ldhHαB were artificially propagated and their swimming stamina compared. The time required to fatigue 50% of the HαAHαA phenotypes in fixed water velocity tests was 2.3 times greater on the average than that of HαAHαB phenotypes.Likewise, LDH phenotypes HαAHαA, HαAHαB, and HαAHαB of steelhead trout from the Thompson River were artifically propagated and their swimming stamina compared. In contrast to the rainbow trout, significant differences in stamina among the three phenotypes of steelhead were not evident in the stocks from this river nor between phenotypes HαAHαB and HαBHαB from another stream, the Vedder River, which has a very low frequency of the ldhHαA allele. The stamina of young steelhead from the Thompson River was, however, 3.8 times greater than that of those from the Vedder River. Key words: stamina, LDH, rainbow trout, steelhead, phenotype, swimming, fatigue

Intra- and inter-specific mitochondrial DNA sequence divergence in Salmo: rainbow, steelhead, and cutthroat trouts

1985 ◽  
Vol 63 (9) ◽  
pp. 2088-2094 ◽  
Author(s):  
Gary M. Wilson ◽  
W. Kelley Thomas ◽  
Andrew T. Beckenbach
Keyword(s):  
Mitochondrial Dna ◽  
Rainbow Trout ◽  
Life Histories ◽  
Sequence Divergence ◽  
Cutthroat Trout ◽  
Restriction Enzymes ◽  
Restriction Endonuclease Analysis ◽  
Salmo Gairdneri ◽  
Intraspecific Divergence ◽  
Clonal Lines

Two forms of Salmo gairdneh with different life histories (steelhead and rainbow trout) were compared using restriction endonuclease analysis of mitochondrial DNA. A total of 19 individuals from four populations were studied for each of the two forms, using 14 restriction enzymes. In addition, five cutthroat trout samples were included as an interspecific comparison. These enzymes revealed a total of 81 cut sites, representing a sample of more than 400 nucleotides per fish. Of these sites, 25 were phylogenetically informative, dividing the 43 fish into 10 clonal lines, 8 Salmo gairdneri and 2 Salmo clarki. Results indicated detectable divergence between all geographic populations of steelhead and rainbow trout except Pennask rainbow trout, Coquihalla steelhead, and Wampus Creek rainbow trout. Other steelhead populations analysed showed a closer phylogenetic relationship to each other than to rainbow trout populations analysed. Intraspecific divergence was in most cases 1% or less, with a 1.5% maximum. Interspecific divergence between S. gairdneri and S. clarki was between 2% and 3.5%.

Rainbow Trout (Salmo gairdneri) and Cutthroat Trout (S. clarki) Interactions in Coastal British Columbia Lakes

1981 ◽  
Vol 38 (10) ◽  
pp. 1228-1246 ◽  
Author(s):  
Nils-Arvid Nilsson ◽  
Thomas G. Northcote
Keyword(s):  
Rainbow Trout ◽  
Aggressive Behavior ◽  
Prey Capture ◽  
Cutthroat Trout ◽  
Maximum Size ◽  
Salmo Gairdneri ◽  
Sympatric Populations ◽  
Food Size ◽  
Coastal British Columbia ◽  
Trout Feeding

Food, size, and growth of 17 allopatric and 10 sympatric lake populations of rainbow trout (Salmo gairdneri) and cutthroat trout (S. clarki) were compared as well as their aggressive behavior during feeding in experimental tanks. In allopatry, rainbow trout fed extensively on benthic, midwater, and surface prey. Allopatric cutthroat utilized mostly midwater prey but in contrast with rainbow trout also fish (Cottus, Gasterosteus) when available. In sympatry, rainbow trout exploited mainly limnetic surface and midwater prey whereas cutthroat trout utilized more littoral prey and were much more piscivorous in feeding. Allopatric rainbow attained a greater average and maximum size (length, weight) than allopatric cutthroat whereas in sympatric populations cutthroat were clearly larger than rainbow. Growth (size at specific ages) usually was higher for rainbow compared with cutthroat trout in allopatric populations but just the reverse in sympatric populations. When held as matched pairs in aquaria, rainbow consistently were more aggressive than cutthroat trout and displayed different patterns of threat as well as means of prey capture. Differences in feeding and growth in sympatry may result from interactive segregation, the more pronounced aggressiveness of rainbow promoting higher growth in cutthroat trout.Key words: rainbow trout, cutthroat trout, feeding, growth, habitat, aggressive behavior, feeding behavior, interactive segregation

Olfactory Bulbar Electrical Responses of Rainbow Trout (Salmo gairdneri) Exposed to Morpholine During Smoltification

1979 ◽  
Vol 36 (10) ◽  
pp. 1186-1190 ◽  
Author(s):  
Toshiaki J. Hara ◽  
S. B. Brown
Keyword(s):  
Rainbow Trout ◽  
Key Words ◽  
Electrical Response ◽  
Salmo Gairdneri ◽  
Induced Responses ◽  
Salmonid Fishes ◽  
Key Words Olfaction ◽  
Sulfhydryl Reagent ◽  
Significant Difference ◽  
Olfactory Organs

Exposure of rainbow trout (Salmo gairdneri) to 5.7 × 10−10 M (5 × 10−5 mg/L) morpholine during smoking period did not influence the subsequent neural response to this substance, when tested immediately and 12 mo after smoking. No significant difference in the morpholine-induced responses was obtained between the exposed and unexposed fish. Using N-ethylmaleimide, a sulfhydryl reagent, it was further confirmed that the morpholine-effect is caused by a mechanism not directly associated with the normal olfactory function. Perfusion of the olfactory organs with 1.0 × 10−1 and 1.1 × 10−1 M (1%) morpholine for 10 min irreversibly inhibited the olfactory responsiveness to odorants. Sensitization of the olfactory bulbar electrical response is discussed in connection with homing of morpholine-imprinted salmonid fishes. Key words: olfaction, olfactory bulbar response, rainbow trout, salmon, imprinting, morpholine, homing, migration

Effect of Extended Galvanonarcosis on Behavior of Rainbow Trout, Salmo gairdneri, and Channel Catfish, Ictalurus punctatus

1978 ◽  
Vol 35 (10) ◽  
pp. 1297-1302 ◽  
Author(s):  
Kevin D. Curry ◽  
Boyd Kynard
Keyword(s):  
Rainbow Trout ◽  
Key Words ◽  
Fish Species ◽  
Direct Current ◽  
Ictalurus Punctatus ◽  
Channel Catfish ◽  
Group Activity ◽  
Salmo Gairdneri ◽  
Prey Vulnerability

Yearling rainbow trout, Salmo gairdneri, and channel catfish, Ictalurus punctatus, were subjected to 0.5- and 3-h periods of narcosis using continuous direct current. Galvanonarcosis treatments decreased the immediate individual and group activity in both species of fish. Twenty-four hours after treatment, all fish except trout narcotized for 3 h recovered to levels of individual and group activity equivalent to those of untreated fish. Photonegative response was strong in both fish species and was not influenced by galvanonarcosis treatments. Trout narcotized with direct current were more vulnerable to predation than untreated fish; susceptability increased with increasing treatment periods. The potential of extended galvanonarcosis as a fish immobilization technique is strong. Key words: galvanonarcosis, behavior, extended narcosis, direct current, rainbow trout, channel catfish, photonegative, activity, prey vulnerability, immobilization

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.

Modification of the Rheotropic Behavior of Male Rainbow Trout (Salmo gairdneri) by Ovarian Fluid

1979 ◽  
Vol 36 (1) ◽  
pp. 63-68 ◽  
Author(s):  
Mary E. Emanuel ◽  
Julian J. Dodson
Keyword(s):  
Rainbow Trout ◽  
Key Words ◽  
Salmo Gairdneri ◽  
Fish Migration ◽  
Odor Plume ◽  
Ovarian Fluid ◽  
Water Currents ◽  
Olfactory Stimuli

The upstream orientation and frequency of upstream movement of ripe male rainbow trout (Salmo gairdneri) in the presence of ovarian fluid obtained from spawning females of the same species were observed and quantified. In a stream tank, male trout moved upstream in the ovarian fluid odor plume. In an optomotor tank, male trout exhibited an increase in the frequency of upstream orientation and movement in the presence of diffuse, nondirectional ovarian fluid. It is concluded that water currents provide directional cues and olfactory stimuli regulate the orientational and kinetic components of the rheotropic response. The significance of this mechanism of orientation in fish migration is discussed. Key words: rheotropism, behavior, olfaction, orientation, migration, ovarian fluid

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