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Marnell, Leo F., Robert J. ,. Behnke i Fred W. Allendorf. "Genetic Identification of Cutthroat Trout, Salmo clarki, in Glacier National Park, Montana". Canadian Journal of Fisheries and Aquatic Sciences 44, nr 11 (1.11.1987): 1830–39. http://dx.doi.org/10.1139/f87-227.
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Trout populations in 29 lakes in Glacier National Park were identified by meristic and electrophoretic analyses to assess the extent of introgressive hybridization between introduced nonnative trout and the indigenous cutthroat trout, Salmo clarki lewisi. Native cutthroat trout remain in 16 lakes draining to the North and Middle forks of the Flathead River; no native trout were found east of the Continental Divide. Introduced Yellowstone cutthroat trout, Salmo clarki bouvieri, occur in six headwater lakes. Hybrid populations, including both S. c. lewisi × bouvieri and S. clarki × S. gairdneri, inhabit six lakes. Hybridization between native and introduced trouts has been minimal, apparently due to strong selective pressures favoring the indigenous genotype. Close agreement was observed between the meristic and electrophoretic results.
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Polgar, Gianluca, Mattia Iaia, Tommaso Righi i Pietro Volta. "The Italian Alpine and Subalpine trouts: Taxonomy, Evolution, and Conservation". Biology 11, nr 4 (11.04.2022): 576. http://dx.doi.org/10.3390/biology11040576.
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During the last 150 years, the trout-culture industry focused on enhancing trout populations by stocking, in response to the growing anglers’ demand and the habitat degradation associated to the rapid urbanization and hydropower development. The industrialized north of Italy, home to the Italian Alpine and subalpine trout populations, is the source of most of the revenues of the national trout-culture industry. Its rapid growth, and the massive introduction of non-native interfertile trouts eroded the genetic diversity of native lineages, leading to harsh confrontations between scientists, institutions, and sportfishing associations. We review here the state of the art of the taxonomy and distribution of the northern Italian native trouts, presenting both scientific results and historical documentation. We think the only native trouts in this region are Salmo marmoratus, widespread in this region, plus small and fragmented populations of S. ghigii, present only in the South-western Alps. We strongly recommend the interruption of stocking of domesticated interfertile non-native trouts in this area, and recommend the adoption of Evolutionary Significant Units for salmonid fishery management. We further propose future research directions for a sustainable approach to the conservation and ecosystem management of the fishery resources and inland waters of northern Italy.
3
Tekeli, H., i A. Bildik. "Effects of age and seasonal temperatures on cortisol levels and GHR, IGF-I, and IGF-II expressions in rainbow trout (Oncorhynchus mykiss)". Journal of the Hellenic Veterinary Medical Society 74, nr 2 (9.07.2023): 5539–46. http://dx.doi.org/10.12681/jhvms.27769.
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The growth hormone (GH)/insulin-like growth factor (IGF) endocrine axis regulates the cellular growth and organ development in related to changing environmental conditions and age. The aim of this study is to determine growth factor genes, which are biological markers of growth in muscle and liver of rainbow trout (Oncorhynchus mykiss) in different seasonal temperatures and age ranges and the reveal of the relationship between serum cortisol (COR) levels from stress parameters. No difference was found in serum COR levels between the groups with respect to temperature and age. Serum GH levels were found to be higher in the summer juvenile trout compared to the winter juvenile and adult trouts. There was no difference in liver growth hormone receptor (GHR) mRNA levels of juvenile and adult trouts in winter while insulin-like growth factor-I (IGF-I) and insulin-like growth factor-II (IGF-II) mRNA levels in liver and muscle tissues were found to be higher in juvenile trout compared to adults. Among trout of different ages, GHR, IGF-I and IGF-II mRNA levels in liver in summer were higher for juvenile trout compared to adults. Muscle IGF-I mRNA levels in summer were higher in adult trout compared to juveniles. IGF-II mRNA levels in liver and muscle tissues of juvenile trout showed an increase in winter compared to in summer. While the GHR and IGF-II mRNA levels in the liver tissue of adult trout were observed to higher in winter compared to summer, IGF-I mRNA levels were found to be higher in summer. GHR, IGF-I and IGF-II mRNA levels in muscle tissue of adult trout were found to be higher in summer than in winter. This study indicated that juvenile and adult rainbow trout (Oncorhynchus mykiss) are adapted to both winter and summer temperature and that GHR, IGF-I and IGF-II genes are highly expressed.
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Rostovtsev, Alexander Alekseevich, Vladimir Ivanovich Romanov i Elena Aleksandrovna Interesova. "Distribution of trout in the Upper Ob basin". Rybovodstvo i rybnoe hozjajstvo (Fish Breeding and Fisheries), nr 6 (1.06.2021): 32–41. http://dx.doi.org/10.33920/sel-09-2106-03.
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Rainbow trout Oncorhynchus mykiss (Walbaum, 1792) and brown trout Salmo trutta Linnaeus, 1758 are popular aquaculture species worldwide. At the same time, it is known that when these species enter natural water bodies, they are able to form self-reproducing populations and cause significant damage to native fauna due to food competition, hybridization with native species, and predation. In the basin of the Upper Ob in the second half of the twentieth century, there was not only a large aquaculture farm specializing in trout but also work was carried out to introduce trout into natural water bodies: lakes in the basins of Lake Teletskoye and the Katun river. It is known about the formation of a self-reproducing population of brook trout in Lake Lebedinoe (in the basin of the Pervaya Koksha River, a second-order tributary of the lower reaches of the Katun River), which still exists. Currently, rainbow trout is a popular object of aquaculture in southern Siberia; it is grown mainly for the purpose of organizing recreational fishing, often in water bodies that are not isolated from the river network. This determines the regular ingress of this species into rivers. Nevertheless, currently no evidence of natural reproduction of trouts in natural water in the Upper Ob basin, except in Lake Lebedinoe. However, given the high risks associated with the potential invasiveness of trouts, it is necessary to recommend a cautious attitude towards the distribution of these species and to provide for an environmental impact assessment of projects related to their cultivation in water bodies of Western Siberia.
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Giantsis, Ioannis A., Argyrios Sapounidis, Emmanouil Koutrakis i Apostolos P. Apostolidis. "Assessment of Stocking Activities on the Native Brown Trout Populations from Nestos River (Southern Balkans) Inferred by mtDNA RFLP and Sequencing Analyses". Applied Sciences 11, nr 19 (28.09.2021): 9034. http://dx.doi.org/10.3390/app11199034.
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Alien fish introductions, conducted towards the ichthyofauna enhancement in local drainages, have been occasionally proved harmful for the indigenous freshwater fish populations. The present study was designed to assess the impact of stocking activities, carried out in the past decades with fingerlings originating from Acheloos river hatcheries, on the native trout (Salmo sp.) populations of Nestos River, Greece. Trout specimens collected from several tributaries of Nestos River and were analyzed by means of PCR-RFLP and sequencing targeting the mitochondrial ND5-ND6 genes and the entire control region, respectively. It should be mentioned that trouts from Acheloos mainly belong to the marmoratus mitochondrial DNA (mtDNA) lineage, while the autochthonous trouts from Nestos belong to the Adriatic lineage. Both methodologies demonstrated that most samples from the three tributaries located at the lower part of Nestos constitute offspring of the fingerlings transferred from Acheloos hatcheries. Therefore, these tributaries have been strongly affected by stocking activities with a potential complete loss of their autochthonous trout. On the other hand, it seems that trout populations from higher altitude tributaries have not been affected by stockings. Hence, efforts should be undertaken in order to prevent the prevalence of the non-indigenous translocated Salmo in higher altitude tributaries, in conjunction with a management plan designed for the total trout populations from the area, speaking of which it has been recently included to the National Park of Rodopi Mountains.
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Vásquez-Machado, Gersson, Miguel Rubiano-Garzón, Jonny Yepes-Blandón, Daniel Gordillo-González i Jersson Avila-Coy. "Weissellosis in rainbow trout in Colombia". Brazilian Journal of Veterinary Pathology 13, nr 3 (26.11.2020): 575–80. http://dx.doi.org/10.24070/bjvp.1983-0246.v13i3p575-580.
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Weissellosis is an emergent disease caused by Weissella, a Gram-positive bacteria correlated with hemorrhagic illness and mortality in farm-raised trout in several countries. The current study reports the first outbreaks of weissellosis by Weissella ceti in rainbow trout (Oncorhynchus mykiss), which caused severe mortalities in trout farms in Colombia between May 2016 to June 2019. The disease occurred in several farms irrigated by the same river where temperatures were above 17 °C. Symptoms of the disease were limited almost exclusively to trout above 250 g. The clinical signs consisted of lethargic and anorexic fish, swimming in circles at the surface or against the walls. Pathological findings were mainly ocular lesions like bilateral exophthalmia, periocular and intraocular hemorrhage, lenticular opacity and corneal rupture usually leading to blindness, muscular hemorrhages and necrosis. Microbial isolating from eye, brain, kidney, liver and muscle was performed and W. ceti was confirmed by amplification and sequencing of the 16S rRNA. The aim of this work was to characterize the Weisellosis by Weissella ceti in trouts in Colombia, including microbiological isolating, molecular analysis, gross and microscopic characterization.
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Denys, Gaël P. J. "A comment on “Morphologic and genetic characterization of Corsican and Sardinian trout with comments on Salmo taxonomy” by Delling et al. (2020): protected Tyrrhenian trouts must be named". Knowledge & Management of Aquatic Ecosystems, nr 422 (2021): 6. http://dx.doi.org/10.1051/kmae/2021006.
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The introduction of the use of molecular data has caused debates on the taxonomy of Corsican and Sardinian trouts, also referred to as Tyrrhenian trouts (i.e. Salmo trutta, Salmo macrostigma, Salmo cettii). A recent study by Delling et al. (2020) (Morphologic and genetic characterization of Corsican and Sardinian trout with comments on Salmo taxonomy. Knowl Manage Aquat Ecosyst 421: 21) introduces important evidence regarding the taxonomy of these populations. However, their subsequent denomination as Salmo sp., that is, an undefined taxon, could have serious consequences on their future conservation management plans. Considering their threatened status, the Tyrrhenian trouts should be referred to as Salmo trutta until the ongoing taxonomic uncertainty can be unambiguously resolved. These populations must then be treated as an Evolutionary Significant Unit (ESU) or as an Operational Conservation Unit (OCU) for further conservation managements plans, as already done for other Mediterranean trout lineages.
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Gomez, Leonardo, Raul Cortes, Ariel Valenzuela i Carlos Smith. "Kinetics of reactive oxygen species produced by rainbow trout (Oncorhynchus mykiss) leukocytes and the effect of the antioxidant astaxanthin". Acta Veterinaria Brno 82, nr 4 (2013): 435–39. http://dx.doi.org/10.2754/avb201382040435.
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Reactive oxygen species contribute to kill of microorganisms. Their activity is usually measured by their capacity to reduce nitroblue tetrazolium into formazan. The incubation time to allow nitroblue tetrazolium reduction by reactive oxygen species usually ranges from 30 to 60 min. The aim of our study was to determine the kinetics of formazan formation, to determine the shortest incubation time possible, and to find if astaxanthin negatively affects the availability of reactive oxygen species (and defense mechanisms of fish). The blood/nitroblue tetrazolium method is based on nitroblue tetrazolium reduction into formazan by reactive oxygen species present in blood. Formazan can be spectrophotometrically measured, allowing quantification of reactive oxygen species. Reactive oxygen species were measured in blood samples from 30 trout intramuscularly injected with astaxanthin (0.3 mg/100 g of fish) (experimental group) and 30 non-injected trout (controls). Results indicated that in trout non-treated with astaxanthin, the plateau of formazan production was reached after 20 min of incubation. Trout intramuscularly injected with astaxanthin showed the following: on Day 1 after astaxanthin injection, the kinetics were slower but finally reached a plateau similar to astaxanthin-free trouts, and by Day 11 the plateau was significantly higher after 60 min incubation. In conclusion, the kinetics curves here reported allow reducing incubation time of the method to only 20 min in antioxidant-free trout and, on the other hand, our results also revealed that astaxanthin can be used to improve flesh colour in salmonids without affecting reactive oxygen species availability and therefore the defense mechanisms of trout.
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Sayers, William. "Trusty Trout, Humble Trout, Old Trout: A Curious Kettle". Nordic Journal of English Studies 8, nr 3 (1.09.2009): 191. http://dx.doi.org/10.35360/njes.203.
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Marr, J. C. A., H. L. Bergman, M. Parker, J. Lipton, D. Cacela, W. Erickson i G. R. Phillips. "Relative sensitivity of brown and rainbow trout to pulsed exposures of an acutely lethal mixture of metals typical of the Clark Fork River, Montana". Canadian Journal of Fisheries and Aquatic Sciences 52, nr 9 (1.09.1995): 2005–15. http://dx.doi.org/10.1139/f95-792.
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Brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss) fry and juveniles were episodically or continuously exposed to a metals mixture (Zn, Cu, Pb, Cd): the concentrations and ratios of the metals, and variations in water quality (pH, hardness), were selected to represent conditions measured during episodic storm events in the Clark Fork River, Montana. Brown trout fry were more sensitive (lower LC50) than rainbow trout fry to the metals in 8-h exposures with constant hardness and pH, but less sensitive to elevated metal concentrations in conjunction with depressed hardness and pH. Fry were more sensitive than juveniles when exposure was continuous, but neither life stage was clearly more sensitive when exposure was pulsed. Whole-body concentrations of K+ and Ca2+ but not Na+ were significantly depressed in fry exposed to metals. Results support the hypotheses that changes in water quality during thunderstorms are lethal to fry and juvenile life stages of brown and rainbow trouts and that the relative sensitivity of the species to the metals mixture may explain their distributions in the Clark Fork River. Low-frequency extreme conditions may effectively act as a bottleneck on the viability of populations whose relative sensitivities to such extremes may control distributions of species in a system.
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SADLER, S. E., G. W. FRIARS i P. E. IHSSEN. "THE INFLUENCE OF TEMPERATURE AND GENOTYPE ON THE GROWTH RATE OF HATCHERY-REARED SALMONIDS". Canadian Journal of Animal Science 66, nr 3 (1.09.1986): 599–606. http://dx.doi.org/10.4141/cjas86-066.
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Growth rates of three salmonid species, brook trout (Salvelinus fontinalis), lake trout (S. namaycush), and rainbow trout (Salmo gairdneri) and one hybrid, splake (S. namaycush × S. fontinalis) were compared at 10 and 16 °C. Two strains of each species, and one of the splake hybrid were examined. At 10 °C the ranking of specific growth rate from highest to lowest for species was: rainbow trout, lake trout, splake, brook trout. At 16 °C the order was: brook trout, rainbow trout, splake, and lake trout. Brook trout, rainbow trout and splake had significantly higher specific growth rates at 16 °C but lake trout showed no difference at the two temperatures. Strain differences were significant in lake trout and rainbow trout, but not in brook trout. Rainbow trout showed a significant strain by temperature interaction. The ranking of feed conversion efficiencies from best to poorest was: lake trout, 10 °C; splake, 10 °C; brook trout, 16 °C; splake, 16 °C; rainbow trout, 16 °C; rainbow trout, 10 °C; lake trout, 16 °C; brook trout, 10 °C. Key words: Temperature, genetics, growth, salmonids, aquaculture
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Barylo, Ye O., Yu V. Loboiko i B. S. Barylo. "Fishery-exteriors characteristics of the brooders of brown trout, rainbow trout and brook trout". Scientific Messenger of LNU of Veterinary Medicine and Biotechnologies 21, nr 90 (26.04.2019): 88–92. http://dx.doi.org/10.32718/nvlvet-a9015.
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This study aims to determine the reproductive indices of three types of salmon fish: brown trout (Salmo trutta morfa fario Linnaeus (1758), rainbow trout (Oncorhynchus mykiss Walbaum, 1792) and brook trout (Salvelinus fontinalis Mitchill, 1814) in aquaculture. For this purpose, 10 females and 10 males of each species were selected on an analogous basis and the main fishery-exteriors and reproductive characteristics were identified. The researching of relative fertility permit to establish that this indicator in brook trout females was 18.36% higher compared to rainbow trout, however, by 7.5% lower compared to the brown trout. It was found that brook trout eggs had less weight and size in comparison with other studied species. In particular, the weight and diameter of the eggs were 2.89 and 9.7% respectively lower than of rainbow trout, as well as 8.1 and 3.44% respectively lower compared to the brown trout. When studying the quantity of ejaculate, it was found that on average, brook trout males had 16.95% less of ejaculates compared to rainbow trout males, but 79.6% more than of brown trout males. When comparing the main indices of the brooders body of the studied species, it was found that the condition factor of the brook trout and rainbow trout females was quite high at 1.55–1.57, the brown trout one was 1.35, and the profile index respectively was 3.5, 3.52 and 4.0. The males' condition factor of brook trout, rainbow trout and brown trout was respectively 1.64, 1.52 and 1.35. Fishery-exteriors indicators met the requirements of brooders species and age specificity norms of the studied fish species.
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Baki, Birol, i Dilara Kaya Öztürk. "Comparative Fatty Acid Compositions of Tissues of Rainbow Trout (Oncorhynchus mykiss) with Different Ploidy and Sex". Turkish Journal of Agriculture - Food Science and Technology 11, nr 10 (25.10.2023): 1994–2002. http://dx.doi.org/10.24925/turjaf.v11i10.1994-2002.6154.
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The purpose of this study was to evaluate the fatty acid contents in various tissues (fillet, liver, gonad) of different ploidy (triploid and diploid) and sex (female and male) rainbow trout (Oncorhynchus mykiss) in the breeding season. In the study, diploid and triploid rainbow trouts belonging to the same age group (3+) were used. Fish were fed with commercial feed containing 45% crude protein and 20% crude fat until satiation. At the end of the 75-day study, biometric measurements of the fish were made and the tissues were stored in a deep freezer until biochemical and fatty acid analysis. The first finding of this study identified that ploidy (triploid and diploid) affects the biochemical and fatty acid composition of rainbow trout. The second major finding was that the polyunsaturated fatty acid values were higher and the saturated fatty acid values were lower in all tissues (especially female gonads) than other fatty acids. The results also indicate that the comparative among the biochemical and fatty acid composition of the fillet, liver, and gonad of rainbow trout is further illuminated by these data.
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Rieman, Bruce E., James T. Peterson i Deborah L. Myers. "Have brook trout (Salvelinus fontinalis) displaced bull trout (Salvelinus confluentus) along longitudinal gradients in central Idaho streams?" Canadian Journal of Fisheries and Aquatic Sciences 63, nr 1 (1.01.2006): 63–78. http://dx.doi.org/10.1139/f05-206.
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Invasions of non-native brook trout (Salvelinus fontinalis) have the potential for upstream displacement or elimination of bull trout (Salvelinus confluentus) and other native species already threatened by habitat loss. We summarized the distribution and number of bull trout in samples from 12 streams with and without brook trout in central Idaho and used hierarchical regression analysis to consider whether brook trout have displaced bull trout along gradients of temperature and elevation. Brook trout generally were observed in higher numbers downstream of bull trout. Brook trout presence, number, and both temperature and elevation were important variables explaining the observed distributions and number of bull trout among streams. Our analyses support the hypothesis that brook trout have displaced bull trout, but results were highly variable and stream dependent. Although brook trout appeared to have displaced bull trout to higher elevations or colder temperatures, there was no clear influence on overall number of bull trout. Brook trout probably do influence bull trout populations and facilitate if not cause local extinctions, but threats probably vary strongly with environmental conditions. Bull trout in smaller streams could be more vulnerable than those in larger streams.
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Seiler, Steven M., i Ernest R. Keeley. "Competition between native and introduced salmonid fishes: cutthroat trout have lower growth rate in the presence of cutthroat–rainbow trout hybrids". Canadian Journal of Fisheries and Aquatic Sciences 66, nr 1 (styczeń 2009): 133–41. http://dx.doi.org/10.1139/f08-194.
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When nonnative species become established within new communities, competition may play a role in determining the persistence of ecologically similar native species. In western North America, many native cutthroat trout ( Oncorhynchus clarkii ) populations have been replaced by nonnative rainbow trout ( Oncorhynchus mykiss ). Superior competitive ability of rainbow trout and cutthroat–rainbow trout hybrids is often cited for this replacement; however, few studies have tested for mechanisms that might allow introduced rainbow trout to out-compete native trout species. Our previous work found individual-based differences in swimming and foraging ability among cutthroat trout, rainbow trout, and their hybrids. In this study, we tested for the presence and strength of competition between cohorts of cutthroat trout, rainbow trout, and their reciprocal hybrids. We assayed the growth rate of juvenile cutthroat trout in allopatry versus cutthroat trout when sympatric with rainbow trout and each hybrid cross. After controlling for size and density of trout, cutthroat trout cohorts in stream channels that contained hybrid genotypes experienced lower growth than cutthroat trout in allopatry. Averaged across heterospecific treatments, cutthroat trout growth was also lower than that of cutthroat trout cohorts in allopatry. Our study suggests that juvenile cutthroat trout experience a growth disadvantage when competing against cutthroat–rainbow hybrids.
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Chivers, Douglas P., Anthony Mathiron, Janelle R. Sloychuk i Maud C. O. Ferrari. "Responses of tadpoles to hybrid predator odours: strong maternal signatures and the potential risk/response mismatch". Proceedings of the Royal Society B: Biological Sciences 282, nr 1809 (22.06.2015): 20150365. http://dx.doi.org/10.1098/rspb.2015.0365.
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Previous studies have established that when a prey animal knows the identity of a particular predator, it can use this knowledge to make an ‘educated guess' about similar novel predators. Such generalization of predator recognition may be particularly beneficial when prey are exposed to introduced and invasive species of predators or hybrids. Here, we examined generalization of predator recognition for woodfrog tadpoles exposed to novel trout predators. Tadpoles conditioned to recognize tiger trout, a hybrid derived from brown trout and brook trout, showed generalization of recognition of several unknown trout odours. Interestingly, the tadpoles showed stronger responses to odours of brown trout than brook trout. In a second experiment, we found that tadpoles trained to recognize brown trout showed stronger responses to tiger trout than those tadpoles trained to recognize brook trout. Given that tiger trout always have a brown trout mother and a brook trout father, these results suggest a strong maternal signature in trout odours. Tadpoles that were trained to recognize both brown trout and brook trout showed stronger response to novel tiger trout than those trained to recognize only brown trout or only brook trout. This is consistent with a peak shift in recognition, whereby cues that are intermediate between two known cues evoke stronger responses than either known cue. Given that our woodfrog tadpoles have no evolutionary or individual experience with trout, they have no way of knowing whether or not brook trout, brown trout or tiger trout are more dangerous. The differential intensity of responses that we observed to hybrid trout cues and each of the parental species indicates that there is a likely mismatch between risk and anti-predator response intensity. Future work needs to address the critical role of prey naivety on responses to invasive and introduced hybrid predators.
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Seiler, Steven M., i Ernest R. Keeley. "Morphological and swimming stamina differences between Yellowstone cutthroat trout (Oncorhynchus clarkii bouvieri), rainbow trout (Oncorhynchus mykiss), and their hybrids". Canadian Journal of Fisheries and Aquatic Sciences 64, nr 1 (1.01.2007): 127–35. http://dx.doi.org/10.1139/f06-175.
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We hypothesized that body shape differences between Yellowstone cutthroat trout (Oncorhynchus clarkii bouvieri), rainbow trout (Oncorhynchus mykiss), and their hybrids may influence swimming ability and thus play an important role in the invasion of nonnative rainbow trout and hybrid trout into native cutthroat trout populations. We reared Yellowstone cutthroat trout, rainbow trout, and reciprocal hybrid crosses in a common environment and conducted sustained swimming trials in order to test for genetically based morphological and swimming stamina differences. Linear and geometric morphometric analyses identified differences in body shape, with cutthroat trout having slender bodies and small caudal peduncles and rainbow trout having deep bodies and long caudal peduncles. Hybrid crosses were morphologically intermediate to the parental genotypes, with a considerable maternal effect. Consistent with morphological differences, cutthroat trout had the lowest sustained swimming velocity and rainbow trout had the highest sustained swimming velocity. Sustained swimming ability of hybrid genotypes was not different from that of rainbow trout. Our results suggest that introduced rainbow trout and cutthroat-rainbow trout hybrids potentially out-compete native Yellowstone cutthroat trout through higher sustained swimming ability.
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Donald, David B., i David J. Alger. "Geographic distribution, species displacement, and niche overlap for lake trout and bull trout in mountain lakes". Canadian Journal of Zoology 71, nr 2 (1.02.1993): 238–47. http://dx.doi.org/10.1139/z93-034.
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Indigenous lacustrine populations of bull trout (Salvelinus confluentus) and lake trout (S. namaycush) are spatially separated within the southern part of the zone of distributional overlap (northern Montana, southwestern Alberta, and east-central British Columbia). In this area, lake trout occurred primarily in mountain lakes of 1032–1500 m elevation, while bull trout were found primarily in lakes between 1500 and 2200 m. Introductions of lake trout in the twentieth century and data obtained from beyond the study area indicated that both fishes can establish significant allopatric populations (more than 5% of the catch) in large, deep lakes (>8 ha in area and >8 m deep) over a wide elevation range. We tested the hypothesis that lake trout displace or exclude bull trout from lakes by determining the outcome of introductions of lake trout into two lakes that supported indigenous bull trout. Lake trout were introduced into Bow Lake in 1964, and by 1992 the bull trout population was decimated there and in another lake (Hector) situated 15 km downstream. Thus, lake trout can displace bull trout and may prevent bull trout from becoming established in certain low-elevation lakes. Population age-structure analyses also suggest that lake trout adversely affected bull trout. Bull trout populations in sympatry with lake trout, including the one extirpated from Hector Lake, had few old fish (18% were more than 5 years old; N = 40 fish from three lakes) compared with allopatric populations (49% were more than 5 years old; N = 235 fish from seven lakes). Niche overlap and the potential for competition between the two char species were substantial. In lakes with trophic structure ranging from simple to complex, bull trout and lake trout fed on similar foods and had similar ecological efficiencies (growth rates). Predation by lake trout on bull trout was not documented during the study.
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Kondratiuk, V. M. "PRODUCTIVITY OF RAINBOW TROUT DEPENDING ON PROTEIN LEVELS IN PRODUCTIVE FEED". Animal Science and Food Technology 11, nr 4 (grudzień 2020): 45–53. http://dx.doi.org/10.31548/animal2020.04.045.
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The article considers the efficiency of using complete feeds with different levels of protein in rearing commercial rainbow trout. The purpose of the experiment was to establish the effect of different protein levels in nutrition of two-year old trout on its productivity. For this purpose, five experimental groups were formed by the method of analogues. During the equalizing period, the experimental fish consumed feed of the control group. In the main period, the protein level in trout feed ranged from 44 to 52 % per 1 kg. As a result of the studies it was established that the increase of protein content in compound feed from 48 to 52 % leads to an increase in the weight of commercial fish by 13.0 % (p < 0.001), an increase in its growth intensity – by 7.4-16.7 %, while the reduction of protein in feed to 44 % leads to a reliable (p < 0.05) reduction in trout weight by 9.4 %, and a decrease in its growth intensity - by 6.5-12.1 %. It is proved that different levels of experimental trout’s protein nutrition have a highly reliable (p < 0.001) effect on the growth of marketable fish - the share of this factor’s influence is 89.8 %. Analysis of the feed costs, proves that using combined feed with 52 % protein for feeding two-year old trout, leads to a decrease in feed costs per 1 kg of weight gain by 5.1 %, whereas reducing this index to 44% causes increase of feed costs by 6.4 % per a unit of product, compared to feeding fish with production feed having the protein content of 48 %. At this, the preservation of experimental fish was high enough and made 94.3 to 96.2 %. In rearing trouts according to the criteria of maximum productivity, it is recommended to feed commercial trout with production combined feeds with the protein level of 52 %, whereas, in production according to the economic optimization criteria, this index should make 48 %.
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Petrosky, C. E., i T. C. Bjornn. "Response of Wild Rainbow (Salmo gairdneri) and Cutthroat Trout (S. clarki) to Stocked Rainbow Trout in Fertile and infertile Streams". Canadian Journal of Fisheries and Aquatic Sciences 45, nr 12 (1.12.1988): 2087–105. http://dx.doi.org/10.1139/f88-243.
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Wild rainbow trout (Salmo gairdneri) and cutthroat trout (S. clarki) were unaffected by stocking of catchable-size rainbow trout in two Idaho streams, except at the highest stocking rates, and even then the effects were limited. In the infertile stream, stocking 50 or 150 trout per section (doubling or tripling the density) did not reduce the abundance of wild cutthroat trout. Wild trout abundance declined at a faster rate in an unreplicated section stocked with 500 trout than in unstocked sections. In the fertile stream, stocking 50 or 100 hatchery trout in sections containing 26–120 similar-sized wild trout did not increase the dispersion or reduce the abundance, growth, or survival rates of wild rainbow trout. When we stocked 400 trout (100 on four dates) in sections containing 32–53 tagged wild trout of similar size, the summer mortality rate of wild trout was higher in stocked than in unstocked sections; the other parameters were not significantly different.
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Maier, K. "Trout". Interdisciplinary Studies in Literature and Environment 20, nr 2 (24.05.2013): 440–41. http://dx.doi.org/10.1093/isle/ist044.
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Bravo, Sandra, Ken Whelan i María Teresa Silva. "Assessment of trout populations inhabiting the Palena River, southern Chile". Latin American Journal of Aquatic Research 49, nr 1 (1.03.2021): 29–39. http://dx.doi.org/10.3856/vol49-issue1-fulltext-2577.
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A survey of trout species was carried out to assess the trout stocks' quality inhabiting the Palena River Basin, one of the most important rivers for recreational angling in Chilean Patagonia. Six sampling campaigns were carried out over 16 selected stretches of the river between February 2012 and June 2013. A total of 912 trout were collected, 57% rainbow trout (Oncorhynchus mykiss), 33.3% brown trout (Salmo trutta), and 9.6% brook trout (Salvelinus fontinalis). Also, one tiger trout (Salmo trutta × Salvelinus fontinalis) (a hybrid between brown and brook trout) was recorded. Results showed that both rainbow trout and brown trout shared the same reaches of the river, with very similar feeding habits, while brook trout inhabited smaller and more enclosed streams. Maturity stages (V-VI) were recorded from the fish sampled over the period spring-summer-autumn in the case of rainbow trout; autumn-winter for brook trout, and summer-autumn for brook trout. One of the study's most notable features was the small size of the mature brook trout, reaching 17.5 cm in length for gravid females and 12.4 cm for mature males at age 2+. The maximum age recorded for rainbow and brown trout was 6+, with a maximum length of 69.8 and 58.5cm, respectively, while for brook trout, the maximum age recorded was 3+ for a female with a length of 29.9 cm length and 2+ for a male of 16.6 cm.
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Spens, Johan, Anders Alanärä i Lars-Ove Eriksson. "Nonnative brook trout (Salvelinus fontinalis) and the demise of native brown trout (Salmo trutta) in northern boreal lakes: stealthy, long-term patterns?" Canadian Journal of Fisheries and Aquatic Sciences 64, nr 4 (1.04.2007): 654–64. http://dx.doi.org/10.1139/f07-040.
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This study of 193 boreal lakes of northern Sweden suggests a long-term detrimental impact of introduced brook trout (Salvelinus fontinalis) on brown trout (Salmo trutta) populations. Thirteen of 65 (20%) brown trout populations in lakes exposed to brook trout went extinct, whereas the extinction rate in unexposed lakes was significantly lower (2%). We verified other studies that indicate that altitude strongly affects the distribution of the two species; brown trout populations in our higher altitude lakes were more sensitive to impact from brook trout. In 28 lakes above 285 m, 12 trout populations exposed to brook trout went extinct, while only one population became extinct in 37 lakes below 285 m. No effects of other environmental factors were detected (e.g., water chemistry, stocking of rainbow trout (Oncorhynchus mykiss), fish species community assembly, migration barriers, or lake morphometry on brown trout extinction). The time lag between the first record of brook trout introduction and subsequent extinction of brown trout was two decades on average (maximum 70 years). Even though further stocking of brook trout has been stopped, our analysis suggest that existing sympatric populations may continue to pose an extinction threat to brown trout.
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BYRNE, C. J., C. V. HOLLAND, R. POOLE i C. R. KENNEDY. "Comparison of the macroparasite communities of wild and stocked brown trout (Salmo trutta L.) in the west of Ireland". Parasitology 124, nr 4 (kwiecień 2002): 435–45. http://dx.doi.org/10.1017/s0031182001001330.
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The aim of the present study was to compare the helminth infra and component communities of wild and stocked brown trout in Lough Feeagh, in the west of Ireland, and also to examine the establishment and development of helminth communities in stocked brown trout. Fish were sampled in May, August and November 1997 and 1998 and an additional sample of wild brown trout was examined in April 1997. In total 217 wild trout and 122 stocked trout were examined. The acanthocephalans Acanthocephalus clavula and Pomphorhynchus laevis were the first parasite species to infect stocked trout in May 1997. In May 1998 both acanthocephalan species along with the trout specialists Eubothrium crassum and Crepidostomum farionis were the first to infect trout. Mean species richness values for stocked trout increased from May to November, in 1997 and 1998. For wild trout, mean species richness values increased from April to November, in 1997 and decreased from May to November in 1998. The parasite communities of wild trout were richer than those of stocked trout in May of both years. In August the parasite communities recorded for wild and stocked trout were similar in terms of the number of species present but differed in terms of structure, and in November the parasite communities of stocked trout were richer than those of wild trout.
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Bozek, Michael A., i Wayne A. Hubert. "Segregation of resident trout in streams as predicted by three habitat dimensions". Canadian Journal of Zoology 70, nr 5 (1.05.1992): 886–90. http://dx.doi.org/10.1139/z92-126.
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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.
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Glassic, Hayley C., Christopher S. Guy, Lusha M. Tronstad, Dominique R. Lujan, Michelle A. Briggs, Lindsey K. Albertson i Todd M. Koel. "Invasive predator diet plasticity has implications for native fish conservation and invasive species suppression". PLOS ONE 18, nr 2 (24.02.2023): e0279099. http://dx.doi.org/10.1371/journal.pone.0279099.
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Diet plasticity is a common behavior exhibited by piscivores to sustain predator biomass when preferred prey biomass is reduced. Invasive piscivore diet plasticity could complicate suppression success; thus, understanding invasive predator consumption is insightful to meeting conservation targets. Here, we determine if diet plasticity exists in an invasive apex piscivore and whether plasticity could influence native species recovery benchmarks and invasive species suppression goals. We compared diet and stable isotope signatures of invasive lake trout and native Yellowstone cutthroat trout (cutthroat trout) from Yellowstone Lake, Wyoming, U.S.A. as a function of no, low-, moderate-, and high-lake trout density states. Lake trout exhibited plasticity in relation to their density; consumption of cutthroat trout decreased 5-fold (diet proportion from 0.89 to 0.18) from low- to high-density state. During the high-density state, lake trout switched to amphipods, which were also consumed by cutthroat trout, resulting in high diet overlap (Schoener’s index value, D = 0.68) between the species. As suppression reduced lake trout densities (moderate-density state), more cutthroat trout were consumed (proportion of cutthroat trout = 0.42), and diet overlap was released between the species (D = 0.30). A shift in lake trout δ13C signatures from the high- to the moderate-density state also corroborated increased consumption of cutthroat trout and lake trout diet plasticity. Observed declines in lake trout are not commensurate with expected cutthroat trout recovery due to lake trout diet plasticity. The abundance of the native species in need of conservation may take longer to recover due to the diet plasticity of the invasive species. The changes observed in diet, diet overlap, and isotopes associated with predator suppression provides more insight into conservation and suppression dynamics than using predator and prey biomass alone. By understanding these dynamics, we can better prepare conservation programs for potential feedbacks caused by invasive species suppression.
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Yau, M. M., i E. B. Taylor. "Cold tolerance performance of westslope cutthroat trout (Oncorhynchus clarkii lewisi) and rainbow trout (Oncorhynchus mykiss) and its potential role in influencing interspecific hybridization". Canadian Journal of Zoology 92, nr 9 (wrzesień 2014): 777–84. http://dx.doi.org/10.1139/cjz-2014-0047.
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Hybridization between rainbow trout (Oncorhynchus mykiss (Walbaum, 1792)) and westslope cutthroat trout (Oncorhynchus clarkii lewisi (Girard, 1856)) occurs commonly when rainbow trout are introduced into the range of westslope cutthroat trout. Typically, hybridization is most common in warmer, lower elevation habitats, but much less common in colder, higher elevation habitats. We assessed the tolerance to cold water temperature (i.e., critical thermal minimum, CTMin) in juvenile rainbow trout and westslope cutthroat trout to test the hypothesis that westslope cutthroat trout better tolerate low water temperature, which may explain the lower prevalence of rainbow trout and interspecific hybrids in higher elevation, cold-water habitats (i.e., the “elevation refuge hypothesis”). All fish had significantly lower CTMin values (i.e., were better able to tolerate low temperatures) when they were acclimated to 15 °C (mean CTMin = 1.37 °C) versus 18 °C (mean CTMin = 1.91 °C; p < 0.001). Westslope cutthroat trout tended to have lower CTMin than rainbow trout from two populations, second–generation (F2) hybrids between two rainbow trout populations, and backcrossed rainbow trout at 15 °C (cross type × acclimation temperature interaction; p = 0.018). Differential adaptation to cold water temperatures may play a role in influencing the spatial distribution of hybridization between sympatric species of trout.
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Öhlund, Gunnar, Fredrik Nordwall, Erik Degerman i Torleif Eriksson. "Life history and large-scale habitat use of brown trout (Salmo trutta) and brook trout (Salvelinus fontinalis) — implications for species replacement patterns". Canadian Journal of Fisheries and Aquatic Sciences 65, nr 4 (1.04.2008): 633–44. http://dx.doi.org/10.1139/f08-003.
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Simple models of temperature-mediated interference competition have generally failed to explain salmonid species replacement patterns along altitudinal gradients, a fact that emphasizes the need to link individual features and their relation to habitat characteristics to population-level dynamics. We compared life history parameters in stream-resident populations of brook trout (Salvelinus fontinalis) and brown trout (Salmo trutta) in eight boreal streams. By use of electrofishing data from 1000 sites, we analyzed and related differences in life history traits to habitat- and interaction-related patterns of growth and densities of brook and brown trout, respectively. Brown trout were competitively dominant throughout the size span of sampled sympatric sites and lowered growth rates in sympatry were mainly caused by environmental factors, revealing a link between brook trout invasions and habitat-related limitations on brown trout performance. Still, the frequency of allopatric brook trout sites increased in the smallest watersheds, indicating that localities with a high degree of brook trout dominance rarely sustain brown trout over time. Brook trout populations had higher turnover rates and proportions of mature females than brown trout populations. Our results suggest growth potential and its effect on population fecundity as a critical factor limiting competitive ability and distribution of brown trout in Swedish brook trout dominated headwaters.
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Wenger, Seth J., Daniel J. Isaak, Jason B. Dunham, Kurt D. Fausch, Charles H. Luce, Helen M. Neville, Bruce E. Rieman i in. "Role of climate and invasive species in structuring trout distributions in the interior Columbia River Basin, USA". Canadian Journal of Fisheries and Aquatic Sciences 68, nr 6 (czerwiec 2011): 988–1008. http://dx.doi.org/10.1139/f2011-034.
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Recent and projected climate warming trends have prompted interest in impacts on coldwater fishes. We examined the role of climate (temperature and flow regime) relative to geomorphology and land use in determining the observed distributions of three trout species in the interior Columbia River Basin, USA. We considered two native species, cutthroat trout ( Oncorhynchus clarkii ) and bull trout ( Salvelinus confluentus ), as well as nonnative brook trout ( Salvelinus fontinalis ). We also examined the response of the native species to the presence of brook trout. Analyses were conducted using multilevel logistic regression applied to a geographically broad database of 4165 fish surveys. The results indicated that bull trout distributions were strongly related to climatic factors, and more weakly related to the presence of brook trout and geomorphic variables. Cutthroat trout distributions were weakly related to climate but strongly related to the presence of brook trout. Brook trout distributions were related to both climate and geomorphic variables, including proximity to unconfined valley bottoms. We conclude that brook trout and bull trout are likely to be adversely affected by climate warming, whereas cutthroat trout may be less sensitive. The results illustrate the importance of considering species interactions and flow regime alongside temperature in understanding climate effects on fish.
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Taniguchi, Yoshinori, Frank J. Rahel, Douglas C. Novinger i Kenneth G. Gerow. "Temperature mediation of competitive interactions among three fish species that replace each other along longitudinal stream gradients". Canadian Journal of Fisheries and Aquatic Sciences 55, nr 8 (1.08.1998): 1894–901. http://dx.doi.org/10.1139/f98-072.
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Competitive ability changed across a range of 3-26°C among three fish species that show longitudinal replacement in Rocky Mountain streams: brook trout (Salvelinus fontinalis) at high elevations, brown trout (Salmo trutta) at middle elevations, and creek chub (Semotilus atromaculatus) at low elevations. Competitive ability was measured by food consumption and aggression in a stream tank. At 20°C, the trout species were competitively equal, and both were competitively superior to creek chub. Creek chub began to have competitive success against brook trout at 22°C and brown trout at 24°C, temperatures stressful but not lethal for the trout. Creek chub became competitively dominant over brook trout at 24°C and brown trout at 26°C, temperatures lethal to a portion of each trout species. We examined whether reduced food consumption was due to appetite loss or the presence of other species. For brook trout, interactions influenced feeding behavior at 22°C, but appetite loss became important at 24°C. For brown trout, interactions influenced feeding behavior at 24°C, but appetite loss became important at 26°C. For creek chub, there was an interaction between behavioral interactions and appetite in determining food consumption. Field data support a transition from trout to non-trout fishes at 22-25°C.
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Peterson, Douglas P., i Kurt D. Fausch. "Upstream movement by nonnative brook trout (Salvelinus fontinalis) promotes invasion of native cutthroat trout (Oncorhynchus clarki) habitat". Canadian Journal of Fisheries and Aquatic Sciences 60, nr 12 (1.12.2003): 1502–16. http://dx.doi.org/10.1139/f03-128.
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To understand how immigration and emigration influence the processes by which invading nonnative brook trout (Salvelinus fontinalis) displace native cutthroat trout (Oncorhynchus clarki), we studied trout movement in long segments of three mountain streams in Colorado during 1999–2001. Over 3500 trout were captured and marked at weirs and during electrofishing, both within and downstream of stream segments. Nearly 80% of brook trout captured at weirs were moving upstream, whereas almost 65% of cutthroat trout were moving downstream. Brook trout movements peaked in early summer and again in fall. Brook trout immigration rates from downstream source populations were high, and in one stream, invaders repopulated a segment where they were removed within 8 months. Immigrant brook trout were typically mature adults in similar body condition to the general population. Brook trout immigrated from a range of distances, with local movement within 250 m more frequently detected, but fish also moved from many distances up to 2 km away within a summer. Brook trout encroachment and invasion was characterized by a wave of local movement exerting biotic pressure on the downstream limit of the cutthroat trout population and jump dispersers moving upstream beyond the invasion front promoting rapid population spread.
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McHugh, Peter, i Phaedra Budy. "An experimental evaluation of competitive and thermal effects on brown trout (Salmo trutta) and Bonneville cutthroat trout (Oncorhynchus clarkii utah) performance along an altitudinal gradient". Canadian Journal of Fisheries and Aquatic Sciences 62, nr 12 (1.12.2005): 2784–95. http://dx.doi.org/10.1139/f05-184.
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Temperature-mediated competition (i.e., dominance shifts between species depending on temperature) may explain the segregation of salmonid species along altitudinal stream gradients. We evaluated this hypothesis for exotic brown trout (Salmo trutta) and native Bonneville cutthroat trout (Oncorhynchus clarkii utah) by rearing them in experimental sympatry and allopatry using enclosures constructed at six sites spaced along a 45-km segment of a mountain stream. For both species, we compared condition and growth between allopatric and sympatric treatment groups. We found that brown trout negatively affected cutthroat trout performance, whereas cutthroat trout failed to impart an effect in the reverse direction, regardless of temperature. Thus, we documented asymmetric competition between these species but found little evidence indicating that its outcome was influenced by temperature. Brown trout cutthroat trout segregation is therefore unlikely to be due to temperature-mediated competition. Instead, brown trout may have displaced cutthroat trout from downstream areas through competition or other mechanisms, while abiotic factors preclude their (brown trout) invasion of upper elevations. Given the magnitude of effect observed in our study, we recommend that brown trout receive greater consideration in cutthroat trout conservation.
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Zimmerman, Julie KH, i Bruce Vondracek. "Interactions of slimy sculpin (Cottus cognatus) with native and nonnative trout: consequences for growth". Canadian Journal of Fisheries and Aquatic Sciences 63, nr 7 (1.07.2006): 1526–35. http://dx.doi.org/10.1139/f06-054.
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We examined growth of native slimy sculpin (Cottus cognatus), native brook trout (Salvelinus fontinalis), and nonnative brown trout (Salmo trutta) to investigate potential interactions of a native nongame fish with native and nonnative trout. Enclosures (1 m2) were stocked with five treatments (juvenile brown trout with sculpin, juvenile brook trout with sculpin, and single species controls) at three densities. Treatments (with replication) were placed in riffles in Valley Creek, Minnesota, and growth rates were measured for six experiments. We examined the difference in growth of each species in combined species treatments compared with each species alone. We did not find evidence of inter actions between brook trout and sculpin, regardless of density or fish size. However, sculpin gained greater mass when alone than with brown trout when sculpin were >16 g. Likewise, brown trout grew more when alone than with sculpin when brown trout were >24 g. In contrast, brown trout ≤5 g grew more with sculpin compared with treatments alone. We suggest that native brook trout and sculpin coexist without evidence of competition, whereas nonnative brown trout may compete with sculpin.
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Warnock, Will G., i Joseph B. Rasmussen. "Abiotic and biotic factors associated with brook trout invasiveness into bull trout streams of the Canadian Rockies". Canadian Journal of Fisheries and Aquatic Sciences 70, nr 6 (czerwiec 2013): 905–14. http://dx.doi.org/10.1139/cjfas-2012-0387.
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An information-theoretic approach was used to determine the association between brook trout (Salvelinus fontinalis) invasiveness and a suite of abiotic and biotic factors, measured at 80 sites from 51 streams in the Canadian Rockies. The streams selected had confirmed brook trout invasions and were identified as current or historical nursery habitat for native bull trout (Salvelinus confluentus). The biomass at most sites was strongly or completely dominated (95%–100%) by one species or the other, and sites were classified as having high brook trout invasiveness (>60% of the biomass of the community relative to remnant bull trout) or low invasiveness (<40%). Among abiotic factors, high brook trout invasiveness was positively associated with stream temperature and undercut bank habitat, but negatively associated with large in-stream substrate (cobbles and boulders). Among biotic factors, brook trout invasiveness was negatively associated with co-occurring rainbow trout (Oncorhynchus mykiss) or brown trout (Salmo trutta), two other introduced species. Brook trout appear to dominate communities over native bull trout where thermal or habitat niche opportunities are provided for them, although other non-native species may restrict their invasion into bull trout streams.
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Al-Chokhachy, Robert, David Schmetterling, Chris Clancy, Pat Saffel, Ryan Kovach, Leslie Nyce, Brad Liermann, Wade Fredenberg i Ron Pierce. "Are brown trout replacing or displacing bull trout populations in a changing climate?" Canadian Journal of Fisheries and Aquatic Sciences 73, nr 9 (wrzesień 2016): 1395–404. http://dx.doi.org/10.1139/cjfas-2015-0293.
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Understanding how climate change may facilitate species turnover is an important step in identifying potential conservation strategies. We used data from 33 sites in western Montana to quantify climate associations with native bull trout (Salvelinus confluentus) and non-native brown trout (Salmo trutta) abundance and population growth rates (λ). We estimated λ using exponential growth state-space models and delineated study sites based on bull trout use for either spawning and rearing (SR) or foraging, migrating, and overwintering (FMO) habitat. Bull trout abundance was negatively associated with mean August stream temperatures within SR habitat (r = −0.75). Brown trout abundance was generally highest at temperatures between 12 and 14 °C. We found bull trout λ were generally stable at sites with mean August temperature below 10 °C but significantly decreasing, rare, or extirpated at 58% of the sites with temperatures exceeding 10 °C. Brown trout λ were highest in SR and sites with temperatures exceeding 12 °C. Declining bull trout λ at sites where brown trout were absent suggest brown trout are likely replacing bull trout in a warming climate.
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Madenjian, Charles P., Daniel V. O'Connor i David A. Nortrup. "A new approach toward evaluation of fish bioenergetics models". Canadian Journal of Fisheries and Aquatic Sciences 57, nr 5 (1.05.2000): 1025–32. http://dx.doi.org/10.1139/f99-280.
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A new approach was used to evaluate the Wisconsin bioenergetics model for lake trout (Salvelinus namaycush). Lake trout in laboratory tanks were fed alewife (Alosa pseudoharengus) and rainbow smelt (Osmerus mordax), prey typical of lake trout in Lake Michigan. Food consumption and growth by lake trout during the experiment were measured. Polychlorinated biphenyl (PCB) concentrations of the alewife and rainbow smelt, as well as of the lake trout at the beginning and end of the experiment, were determined. From these data, we calculated that lake trout retained 81% of the PCBs contained within their food. In an earlier study, application of the Wisconsin lake trout bioenergetics model to growth and diet data for lake trout in Lake Michigan, in conjunction with PCB data for lake trout and prey fish from Lake Michigan, yielded an estimate of PCB assimilation efficiency from food of 81%. This close agreement in the estimates of efficiency with which lake trout retain PCBs from their food indicated that the bioenergetics model was furnishing accurate predictions of food consumption by lake trout in Lake Michigan.
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Guy, Christopher S., Thomas E. McMahon, Wade A. Fredenberg, Clinton J. Smith, David W. Garfield i Benjamin S. Cox. "Diet Overlap of Top-Level Predators in Recent Sympatry: Bull Trout and Nonnative Lake Trout". Journal of Fish and Wildlife Management 2, nr 2 (1.12.2011): 183–89. http://dx.doi.org/10.3996/012011-jfwm-004.
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Abstract The establishment of nonnative lake trout Salvelinus namaycush in lakes containing lacustrine–adfluvial bull trout Salvelinus confluentus often results in a precipitous decline in bull trout abundance. The exact mechanism for the decline is unknown, but one hypothesis is related to competitive exclusion for prey resources. We had the rare opportunity to study the diets of bull trout and nonnative lake trout in Swan Lake, Montana during a concomitant study. The presence of nonnative lake trout in Swan Lake is relatively recent and the population is experiencing rapid population growth. The objective of this study was to evaluate the diets of bull trout and lake trout during the early expansion of this nonnative predator. Diets were sampled from 142 bull trout and 327 lake trout during the autumn in 2007 and 2008. Bull trout and lake trout had similar diets, both consumed Mysis diluviana as the primary invertebrate, especially at juvenile stages, and kokanee Oncorhynchus nerka as the primary vertebrate prey, as adults. A diet shift from primarily M. diluviana to fish occurred at similar lengths for both species, 506 mm (476–545 mm, 95% CI) for bull trout and 495 mm (470–518 mm CI) for lake trout. These data indicate high diet overlap between these two morphologically similar top-level predators. Competitive exclusion may be a possible mechanism if the observed overlap remains similar at varying prey densities and availability.
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Alimova, Aziza, Boymakhmat Kakhramanov i Feruza Safarova. "Water quality indicators in high-density cage farming of trout". BIO Web of Conferences 65 (2023): 04003. http://dx.doi.org/10.1051/bioconf/20236504003.
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Trout fishing means raising fish in water whose temperature does not exceed +18°C under completely or partially artificial conditions. Today, several fish belonging to the salmon family are bred in cold water fisheries in the world. These are river trout (Rainbow trout - Oncorhynchus mykiss), brook trout (Brown trout - Salmo trutta), and brown trout (Brook trout - Salvelinus fontinalis). Currently, river trout breeding dominates global production. Its cultivation has been mastered in almost all regions [8]. In the article, the water quality indicators were studied during high-density breeding of trout in the cage method at the “Golden Fish” fishery LLC, located in the Khojakent reservoir in the Tashkent region of Uzbekistan. This includes water temperature, dissolved oxygen content, and water hydrogen potential, as well as information on fish growth, development, nutrition, and reproduction.
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Meyer, Kevin A., Erin I. Larson, Christopher L. Sullivan i Brett High. "Trends in the Distribution and Abundance of Yellowstone Cutthroat Trout and Nonnative Trout in Idaho". Journal of Fish and Wildlife Management 5, nr 2 (1.06.2014): 227–42. http://dx.doi.org/10.3996/092013-jfwm-062.
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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.
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CAMPBELL, MATTHEW A., ENSIEH HABIBI, GRACE AURINGER, MOLLY STEPHENS, JEFF RODZEN, KEVIN W. CONWAY i AMANDA J. FINGER. "Molecular Systematics of Redband Trout from Genome-Wide DNA Sequencing Substantiates the Description of a New Taxon (Salmonidae: Oncorhynchus mykiss calisulat) from the McCloud River". Zootaxa 5254, nr 1 (9.03.2023): 1–29. http://dx.doi.org/10.11646/zootaxa.5254.1.1.
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Rainbow Trout, Oncorhynchus mykiss, exhibit high levels of phenotypic diversity leading to the recognition of numerous subspecies. A major distinction among Rainbow Trout subspecies exists between Coastal Rainbow Trout (O. m. irideus), which occurs west of the Cascade and Sierra Nevada mountain ranges, and interior Redband Trout (O. mykiss sspp.), largely distributed to the east. Interior Redband Trout are composed of three primary lineages and can share various outward, anatomical or physiological characteristics that are often symplesiomorphies or examples of convergence. We examine high-throughput DNA sequence data from Sacramento Redband Trout O. m. stonei from the Upper Pit and Upper McCloud Rivers along with representatives of Rainbow Trout and Golden Trout lineages to clarify the composition and relationships of the Sacramento Redband Trout. We find O. m. stonei to be polyphyletic, divided between populations in the Pit River and the Upper McCloud River. Redband Trout obtained from the Pit River are most-closely related to Great Basin Redband Trout O. m. newberrii and to fish of the Warner Lakes Basin and Surprise Valley within the O. m. newberrii lineage. The type specimen of O. m. stonei, collected from the Lower McCloud River, is phenotypically similar to Great Basin Redband Trout. We find as well that the isolated populations of trout in the Upper McCloud River Basin represent a lineage of Rainbow Trout now restricted to that region, are monophyletic and are not most closely related to the interior Redband Trout lineages of O. m. newberrii or O. m. gairdnerii. Furthermore, they are not represented by the type specimens of O. m. stonei or O. m. shasta. Consequently, we formally describe the McCloud River Redband Trout O. mykiss calisulat, new subspecies.
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Hitt, Nathaniel P., Erin L. Snook i Danielle L. Massie. "Brook trout use of thermal refugia and foraging habitat influenced by brown trout". Canadian Journal of Fisheries and Aquatic Sciences 74, nr 3 (marzec 2017): 406–18. http://dx.doi.org/10.1139/cjfas-2016-0255.
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The distribution of native brook trout (Salvelinus fontinalis) in eastern North America is often limited by temperature and introduced brown trout (Salmo trutta), the relative importance of which is poorly understood but critical for conservation and restoration planning. We evaluated effects of brown trout on brook trout behavior and habitat use in experimental streams across increasing temperatures (14–23 °C) with simulated groundwater upwelling zones providing thermal refugia (6–9 °C below ambient temperatures). Allopatric and sympatric trout populations increased their use of upwelling zones as ambient temperatures increased, demonstrating the importance of groundwater as thermal refugia in warming streams. Allopatric brook trout showed greater movement rates and more even spatial distributions within streams than sympatric brook trout, suggesting interference competition by brown trout for access to forage habitats located outside thermal refugia. Our results indicate that removal of introduced brown trout may facilitate native brook trout expansion and population viability in downstream reaches depending in part on the spatial configuration of groundwater upwelling zones.
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Johnsson, Jörgen I., W. Craig Clarke i Ruth E. Withler. "Hybridization with Domesticated Rainbow Trout (Oncorhynchus mykiss) Reduces Seasonal Variation in Growth of Steelhead Trout (O. mykiss)". Canadian Journal of Fisheries and Aquatic Sciences 50, nr 3 (1.03.1993): 480–87. http://dx.doi.org/10.1139/f93-056.
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We tested the hypothesis that hybridization with domesticated rainbow trout (Oncorhynchus mykiss) reduces the seasonal variation in growth in both fresh and salt water in anadromous steelhead trout (O. mykiss). The seasonal variation in freshwater growth was more pronounced in the steelhead trout than in the hybrid and domesticated trout. Consequently, differences in growth rate among groups were considerably higher during winter than in fall or spring. We suggest that high feeding activity during unfavourable winter conditions in natural waters is maladaptive, but is not selected against in protected hatchery environments with a continuous food supply. This may lead to genetic divergence in feeding physiology and/or behaviour between steelhead trout and domesticated rainbow trout. Growth rates in experimental groups transferred to seawater in December relative to groups transferred in April were faster in rainbow and hybrid trout than in steelhead trout. The results support the hypothesis that seasonal variation in seawater growth in steelhead trout is reduced by crossing with domesticated rainbow trout.
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Bazaz, Asim Iqbal, Tasaduq H. Shah, Farooz A. Bhat, Irfan Ahmad, Nafhat-ul-Arab -, Maheen Altaf, Saima Andleeb, Zaib Hafiz, Bisma Shafi i Azra Shah. "Assessment of Spawning Fecundity and Its Relationship with Body Parameters of Rainbow Trout (Oncorhynchus mykiss) and Brown Trout (Salmo trutta fario)". International Journal of Bio-resource and Stress Management 13, nr 10 (31.10.2022): 1115–23. http://dx.doi.org/10.23910/1.2022.3066a.
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The present investigations were carried out at Trout Culture Farm Laribal, Srinagar (J&K Govt.), India during December, 2020. Relationship between length-weight, spawning fecundity and relative fecundity was observed in rainbow trout (O. mykiss) and brown trout (S. trutta fario). The mean length of male rainbow trout was (38.77±1.38 cm) and mean length of (38.05±1.32 cm) was observed in female rainbow trout. While as, the mean length of male brown trout was (38.86±1.41 cm) and for female brown trout mean length of (37.98±1.30 cm) was observed. The mean weight of male and female rainbow trout recorded was 794.6±49.3 g and 766.3±64.3 g respectively, while as, the average weight of male and female brown trout was 772.7±41.4 g and 757.6±57.22 g respectively. The spawning fecundity female-1 of rainbow trout ranged from 2002−2804 eggs and mean relative fecundity of 3.13±0.12 g-1 body weight was observed and for brown trout the spawning fecundity female-1 fish ranged from 961 to 1604 eggs, with a relative fecundity of 1.41 g-1 body weight to 1.56 g-1 body weight. The present study recorded a significant positive correlation between total body length and total body weight of male rainbow trout (r=0.938, p<0.05) and total body length and total body weight of female rainbow trout (r=0.989, p<0.05) and for brown trout a significant positive correlation was recorded between total body length and spawning fecundity, body weight and spawning fecundity was observed. However, relative fecundity formed a significant negative correlation between total length, body weight and spawning fecundity in brown trout.
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Warnock, Will G., i Joseph B. Rasmussen. "Assessing the effects of fish density, habitat complexity, and current velocity on interference competition between bull trout (Salvelinus confluentus) and brook trout (Salvelinus fontinalis) in an artificial stream". Canadian Journal of Zoology 91, nr 9 (wrzesień 2013): 619–25. http://dx.doi.org/10.1139/cjz-2013-0044.
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In this experiment, competition was observed among native bull trout (Salvelinus confluentus (Suckley, 1859)) and non-native brook trout (Salvelinus fontinalis (Mitchill, 1814)) in artificial streams. In intraspecific competitions, brook trout engaged in territorial interference foraging strategies, and their foraging success was correlated with occupancy of the lead position in the stream. No correlation was apparent for bull trout, most of which engaged in nonterritorial scramble foraging tactics. In interspecific competitions, four stream environments were constructed in which fish density, habitat complexity, and current velocity were altered. Bull trout outcompeted brook trout for food in simple pool habitat devoid of cover when competition was head-to-head (density = 3 fish·m−2) between the species. When competitor number was doubled in this habitat, the two became equal competitors. At this higher density, bull trout again outcompeted brook trout for food when the habitat was changed to a complex riffle with substrate cover. Brook trout were more aggressive towards bull trout than vice versa, and interspecific aggression was decreased by low density, cover, and high stream velocity. Territorial brook trout aggressively interfere with their competitor for access to resources, but the success and intensity of this tactic against bull trout may be mitigated by environmental factors.
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Reeves, Gordon H., Fred H. Everest i James D. Hall. "Interactions Between the Redside Shiner (Richardsonius balteatus) and the Steelhead Trout (Salmo gairdneri) in Western Oregon: The Influence of Water Temperature". Canadian Journal of Fisheries and Aquatic Sciences 44, nr 9 (1.09.1987): 1603–13. http://dx.doi.org/10.1139/f87-194.
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Water temperature influenced interactions between redside shiner (Richardsonius balteatus) and juvenile steelhead trout (Salmo gairdneri) (≥1 +) in the field and laboratory. Trout in cool water when shiner were absent and at intermediate water temperatures with shiner present occupied a similar range of habitats. Shiner alone in warm water occupied habitats similar to trout, but in the presence of trout occupied slower, deeper areas than when alone. In laboratory streams, production by trout was the same in the presence and absence of shiner in cool water (12–15 °C). In warm water (19–22 °C), production by trout decreased by 54% in the presence of shiner compared with when shiner were absent. Production of shiner in cool water decreased in the presence of trout, −0.3 g∙m−2∙d−1 together compared with 0.5 g∙m−2∙d−1 alone, but was not affected by the presence of trout in warm water. Trout distribution was not influenced by shiner in cool waters, but was influenced at warm temperatures. Shiner occupied all areas of the laboratory channels in the absence of trout in cool waters but were restricted to a few pools in the presence of trout. Distribution of shiner was not influenced by trout at warm temperatures.
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Swanson, Heidi K., Karen A. Kidd, John A. Babaluk, Rick J. Wastle, Panseok P. Yang, Norman M. Halden i James D. Reist. "Anadromy in Arctic populations of lake trout (Salvelinus namaycush): otolith microchemistry, stable isotopes, and comparisons with Arctic char (Salvelinus alpinus)". Canadian Journal of Fisheries and Aquatic Sciences 67, nr 5 (maj 2010): 842–53. http://dx.doi.org/10.1139/f10-022.
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In the family Salmonidae, lake trout ( Salvelinus namaycush ) are considered the least tolerant of salt water. There are, however, sporadic reports of lake trout in coastal, brackish habitats in the Canadian Arctic. Otolith microchemistry analyses conducted on lake trout and Arctic char ( Salvelinus alpinus ) from four Arctic lakes in the West Kitikmeot region of Nunavut, Canada, revealed that 37 of 135 (27%) lake trout made annual marine migrations. Anadromous lake trout were in significantly better condition (K = 1.17) and had significantly higher C:N ratios (3.71) than resident lake trout (K = 1.05 and C:N = 3.34). Anadromous lake trout also had significantly higher δ15N (mean = 16.4‰), δ13C (mean = –22.3‰), and δ34S (mean = 13.43‰) isotope ratios than resident lake trout (means = 12.84‰, –26.21‰, and 1.93‰ for δ15N, δ13C, and δ34S, respectively); results were similar for Arctic char and agree with results from previous studies. Mean age of first migration for lake trout was 13 years, which was significantly older than that for Arctic char (5 years). This could be a reflection of size-dependent salinity tolerance in lake trout, but further research is required. These are the first detailed scientific data documenting anadromy in lake trout.
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Maki-Petäys, A., T. Muotka, A. Huusko, P. Tikkanen i P. Kreivi. "Seasonal changes in habitat use and preference by juvenile brown trout, Salmo trutta, in a northern boreal river". Canadian Journal of Fisheries and Aquatic Sciences 54, nr 3 (1.03.1997): 520–30. http://dx.doi.org/10.1139/f96-311.
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By means of electrofishing, we examined seasonal and size-class variation in habitat preference by juvenile brown trout (Salmo trutta) in a third-order river in northern Finland. Larger trout preferred deeper stream areas than young-of-the-year fish. At the onset of winter, all trout size-classes moved into shallower water, but this mainly reflected seasonal variation in habitat availability. In winter, trout preferred slowly flowing stream areas, whereas in other seasons the mean water velocities used by trout parallelled habitat availability. In summer and autumn, age-0 fish favoured stream areas with large amounts of aquatic vegetation to provide cover. The largest trout (16-22 cm) occupied habitats with little cover throughout the year, and in winter, all trout avoided areas with high instream cover. In summer, all size-classes preferred small substrates, whereas in winter, areas with cobble-boulder substrates were preferred, especially by trout larger than 10 cm. Wintering trout often shelter among the interstitial spaces of coarse substrates, and to facilitate the survival of juvenile trout through winter, stream management programmes need to ensure that such particles are abundantly available in trout wintering areas.
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Banish, Nolan P., William R. Tinniswood i Terry A. Smith. "Electrofishing, Snorkel Spearing, and Piscicide Eradicate Brook Trout From a Small, Isolated Bull Trout Population". Journal of Fish and Wildlife Management 10, nr 1 (1.02.2019): 219–27. http://dx.doi.org/10.3996/092018-jfwm-088.
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Abstract In 1992, a sampling crew from a multiagency group discovered a population of Bull Trout Salvelinus confluentus estimated at approximately 50 individuals in Threemile Creek, Oregon threatened with competition and hybridization with nonnative Brook Trout Salvelinus fontinalis. The group implemented Brook Trout and Bull Trout × Brook Trout hybrid removal using multiple techniques to conserve this population of Bull Trout in the Klamath River basin. From 1996 to 2000, backpack electrofishing and night snorkel spearing were used upstream of a culvert barrier to eradicate Brook Trout and hybrid trout from a 3.59-km section of Threemile Creek over 101 total days of effort (274 person-days of effort). Night snorkel spearing removed a lower percentage (7%) of target fish relative to electrofishing (93%), although this technique eliminated the risk of electrofishing injury to Bull Trout. Concurrent with the reduction and subsequent removal of Brook Trout, Bull Trout observations increased over 15-fold from 19 in 1996 to 299 in 2012 and Bull Trout distribution more than doubled, from 1.48 to 3.43 km during that same time. Immediately downstream in a separate 2.3-km section, the group eradicated Brook Trout using backpack electrofishing and rotenone application upstream of two man-made barriers from 2004 to 2010 over 43 total days of effort (150 person-days of effort). By 2016, Bull Trout had expanded their distribution throughout the upper 3.59-km section of Threemile Creek. Effort expended to eradicate Brook Trout was similar to successful eradication in other streams with comparable habitat characteristics and similar treatment length (< 3.0 km). However, similar removal attempts have not been successful in streams with comparable habitat characteristics that had longer treatment length (> 7.0 km). Application of piscicide may be more cost effective than manual techniques to remove Brook Trout when there is no risk to native fish of conservation concern, where target species are allopatric, and when piscicide use is publicly accepted. Brook Trout eradication proved valuable in providing Bull Trout the opportunity for range expansion and increased abundance necessary for recovery in the Klamath River basin.
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Meeuwig, Michael H., i Mary M. Peacock. "Food Web Interactions Associated With a Lahontan Cutthroat Trout Reintroduction Effort in an Alpine Lake". Journal of Fish and Wildlife Management 8, nr 2 (1.07.2017): 449–64. http://dx.doi.org/10.3996/092016-jfwm-073.
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Abstract Fisheries managers have stocked Lahontan Cutthroat Trout Oncorhynchus clarkii henshawi into Fallen Leaf Lake, California, since 2002 in an attempt to reestablish a naturally reproducing lacustrine population. However, the food web in Fallen Leaf Lake has been altered by the past introduction of nonnative species that may prey on or compete with reintroduced Lahontan Cutthroat Trout. Therefore, we used a combination of stomach content and stable isotope analyses to evaluate trophic characteristics within the aquatic species assemblage in Fallen Leaf Lake. Lahontan Cutthroat Trout preyed on mysid shrimp Mysis diluviana, aquatic insects, terrestrial arthropods, signal crayfish Pacificus leniusculus, and fishes. Diet overlap was greatest between Lahontan Cutthroat Trout and Mountain Whitefish Prosopium williamsoni; however, these species exhibited a generalized feeding strategy that may allow them to partition prey resources in order to avoid competitive interactions. Nonnative Lake Trout Salvelinus namaycush and Brown Trout Salmo trutta are top-level predators in Fallen Leaf Lake and both consumed Lahontan Cutthroat Trout during this study. Lake Trout δ13C and δ15N increased following Lahontan Cutthroat Trout stocking, a change consistent with incorporating isotopically enriched Lahontan Cutthroat Trout into their diet. Managers should consider the effects of predation by Lake Trout and Brown Trout on Lahontan Cutthroat Trout when developing future management and stocking programs for Fallen Leaf Lake. Additionally, intentional manipulation of the isotopic composition of hatchery-reared fish prior to stocking may be useful for evaluating predation in Fallen Leaf Lake and other systems.
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Mruk, A., G. Kucheruk, L. Galoyan i N. Mykhailenko. "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". Ribogospodarsʹka nauka Ukraïni., nr 4(58) (22.12.2021): 40–55. http://dx.doi.org/10.15407/fsu2021.04.040.
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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.