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1.
Abstract – Sixty-five large (>385 mm fork length) bull trout ( Salvelinus confluentus ), a threatened relict charr (Family Salmonidae), were captured in the upper East Fork South Fork Salmon River (EFSFSR), Idaho, USA and implanted with radio tags to investigate their spatial and temporal movements and distribution throughout the South Fork Salmon River (SFSR) basin and beyond. All radio-tagged fish were migratory. Most fish displayed a fluvial migration pattern. They typically overwintered in the larger rivers downriver of the EFSFSR (SFSR and the Salmon River further downstream), migrated upriver to the EFSFSR in June and further upriver into small (<2 m wide) tributaries to spawn in August and September. Both consecutive-year and nonconsecutive-year spawners were found. A typical migration distance between the overwintering habitat and the spawning habitat was 100 km. A minor fraction (<10%) of the fish displayed an adfluvial life history pattern, overwintering in a small (2 ha) 60-year-old flooded mine pit in the EFSFSR upstream of the spawning tributaries. The stock exhibited distinct site fidelity for spawning and overwintering. Similar fluvial and adfluvial migration patterns have been reported for bull trout in the region as well as for other charr species worldwide. Effective management of this and other migratory charr stocks will require protection of a wide range of habitats, from large rivers to the smallest tributaries. 相似文献
2.
Bull trout, Salvelinus confluentus (Suckley), populations are declining in many streams of North America and are listed under the Endangered Species Act in the United States. Many small populations are isolated in fragmented habitats where spawning conditions and success are not well understood. Factors affecting habitats selected for redds by spawning bull trout and redd habitat characteristics within Gold Creek, a headwater stream in the Yakima River within the Columbia River basin, Washington State, USA, were evaluated. Most spawning (>80% of the redds) occurred in upstream habitats after dewatering of downstream channels isolated fish. Habitats were selected or avoided in proportions different to their availability. For example, most bull trout selected pools and glides and avoided riffles despite the latter being more readily available. Although preferences suggest influences of prolonged fish entrapment, site fidelity could be important. A habitat with redds commonly contained abundant cover, gravel substratum and higher stream flows. The major factors influencing habitat selection by spawning fish and their persistence in streams of the Yakima and Columbia River regions include entrapment of fish by dewatering of channels and geographical isolation by dams. The goal of the US Government's recovery plan is ‘to ensure the long‐term persistence of self‐sustaining bull trout populations’. Recovery plans linked to provisions for protecting and conserving bull trout populations and their habitats were recommended. Landscape approaches are needed that provide networks of refuge habitats and greater connectivity between populations. Concurrent recovery efforts are encouraged to focus on protecting small populations and minimizing dangers of hybridization. 相似文献
3.
Abstract – Movement and habitat use by bull trout ( Salvelinus confluentus ) was examined using radio telemetry in the Morice River watershed, north-western British Columbia, between April 2000 and November 2001. Bull trout principally utilised mainstem habitat. Throughout the watershed, little movement was observed during the winter months. From June to September, movement increased and was correlated with migration into tributaries. We directly observed spawning bull trout only in tributaries of the Morice River and never in the mainstem. Many of the fish ( N = 48) migrated to the nearest potential spawning sites, but a few fish ( N = 7) made extensive migrations to other regions of the watershed to spawn. Fish that spawned in both years of the study returned to the same spawning location. Variation in spatial and movement data, therefore, appears to be linked to availability of suitable habitat and not differences in life history that have been observed in large bull trout. 相似文献
4.
Genetic population structure within streams: microsatellite analysis of bull trout populations 总被引：1，自引：1，他引：0
P. Spruell B. E. Rieman K. L. Knudsen F. M. Utter F. W. Allendorf 《Ecology of Freshwater Fish》1999,8(3):114-121
Abstract– We used six polymorphic microsatellite loci to investigate a potential metapopulation system in bull trout ( Salvelinus confluentus ) from five spawning localities in the Lightning Creek drainage, a tributary to Lake Pend Oreille, Idaho. The number of spawners as estimated by redd counts is low in all populations sampled. Analytic viability models indicate that local isolated populations of these sizes are unlikely to persist. We tested two hypotheses: (1) these are remnant populations that are vulnerable to local extinction, or (2) these populations are interconnected by migration and are being maintained at larger effective sizes than indicated by the redd counts (i. e. metapopulation dynamics). All populations within the Lightning Creek basin are significantly differentiated ( P > 0.005), and the allele frequencies appear to be stable among temporally separated subsamples within locations. It is therefore unlikely that extensive dispersal has linked tributaries in a manner consistent with a metapopulation structure. The low number of spawning individuals combined with the degree of isolation indicated by the genetic data suggest that extinction of the tributary populations is probable if temporal variability and small size is prolonged. However, these populations contain amounts of genetic variation similar to populations throughout the range of bull trout. Therefore, if the apparent demographic trends are reversed, these populations may recover without suffering the detrimental effects of a severe bottleneck. 相似文献
5.
Esben A. Kristensen Gerard P. Closs Ricky Olley Jonathan Kim Malcolm Reid Claudine Stirling 《Ecology of Freshwater Fish》2011,20(3):377-383
Abstract – Strontium (Sr) content of eggs collected from redds were used to determine the spawning contribution of resident and anadromous female brown trout in the Taieri River, New Zealand and were analysed on the catchment and tributary scale. At the catchment scale, analysis of Sr showed differences between eggs collected above and below the Taieri River Gorge. Samples collected above the gorge all had low‐Sr concentrations similar to levels found in an entirely resident brown trout population. Samples collected below the gorge exhibited a broad range in Sr concentrations, ranging from levels comparable to the known anadromous samples to levels comparable to the known freshwater‐resident samples. This suggests that the gorge prevents upstream migration by anadromous brown trout in the Taieri River. At the tributary scale, this pattern of anadromous brown trout spawning downstream of freshwater‐resident fish was repeated in one of the two tributaries located downstream of the gorge. Energetic cost of migration is the most likely explanation for the observed patterns in catchment and tributary scale distribution of spawning by resident and anadromous brown trout. It is concluded that the use of Sr concentrations in eggs collected from redds is a cost‐effective and reliable method to investigate the spawning contribution by anadromous brown trout. 相似文献
6.
Modelling individual variability in growth of bull trout in the Walla Walla River Basin using a hierarchical von Bertalanffy growth model 
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下载免费PDF全文 Julianne E. Harris Courtney Newlon Philip J. Howell Ryan C. Koch Steven L. Haeseker 《Ecology of Freshwater Fish》2018,27(1):103-115
We examined growth in length of fluvial bull trout (Salvelinus confluentus) in the Walla Walla River Basin, Washington and Oregon. Our objectives were to quantify individual variability in growth; examine growth within and among years, life history forms, life stages and sexes; and estimate von Bertalanffy growth parameters. Individual variability was evaluated by modelling asymptotic length (L∞) and the growth coefficient (k) as random variables. All models were fit with Bayesian methods and were evaluated for fit by the deviance information criterion. By incorporating individual variability, population‐level estimates of L∞ and k appeared appropriate and estimated growth trajectories for specific bull trout fit individual observed patterns in growth. Growth trajectories and positive correlation between individual estimates of L∞ and k suggest that some individuals grow at a faster rate and reach a larger maximum size than other individuals and those differences are maintained throughout life. Selected models suggest that fluvial migrants have higher estimates of L∞ and k than residents, but there were only slight differences in parameter estimates among migrants from two adjacent spawning populations in the Walla Walla River Basin, as well as between males and females. Growth rates increased for fluvial migrants after subadult emigration. Individual variability in growth is consistent with the life history diversity assumed essential for bull trout population persistence. Quantifying this variability is important for modelling population dynamics and viability to conserve this threatened species. 相似文献
7.
Howell PJ, Dunham JB, Sankovich PM. Relationships between water temperatures and upstream migration, cold water refuge use, and spawning of adult bull trout from the Lostine River, Oregon, USA.Ecology of Freshwater Fish 2010: 19: 96–106. This article is a US Government work and is in the public domain in the USA Abstract – Understanding thermal habitat use by migratory fish has been limited by difficulties in matching fish locations with water temperatures. To describe spatial and temporal patterns of thermal habitat use by migratory adult bull trout, Salvelinus confluentus, that spawn in the Lostine River, Oregon, we employed a combination of archival temperature tags, radio tags, and thermographs. We also compared temperatures of the tagged fish to ambient water temperatures to determine if the fish were using thermal refuges. The timing and temperatures at which fish moved upstream from overwintering areas to spawning locations varied considerably among individuals. The annual maximum 7‐day average daily maximum (7DADM) temperatures of tagged fish were 16–18 °C and potentially as high as 21 °C. Maximum 7DADM ambient water temperatures within the range of tagged fish during summer were 18–25 °C. However, there was no evidence of the tagged fish using localized cold water refuges. Tagged fish appeared to spawn at 7DADM temperatures of 7–14 °C. Maximum 7DADM temperatures of tagged fish and ambient temperatures at the onset of the spawning period in late August were 11–18 °C. Water temperatures in most of the upper Lostine River used for spawning and rearing appear to be largely natural since there has been little development, whereas downstream reaches used by migratory bull trout are heavily diverted for irrigation. Although the population effects of these temperatures are unknown, summer temperatures and the higher temperatures observed for spawning fish appear to be at or above the upper range of suitability reported for the species. 相似文献
8.
Abstract – Redband trout (Oncorhynchus mykiss gairdneri) migrations were tracked between March 2007 and June 2009 in the Donner und Blitzen River, Oregon, USA, using radio telemetry and PIT tags. We investigated the upstream extent and timing of spawning migrations for two groups of trout, considered the factors that influenced the rate of trout migration and explored the seasonal patterns of redband trout migration related to temperature and flow conditions. We found that trout made long‐distance migrations (up to 91 km) to spawn. Spawning trout from the lower river and middle river migrated to the same reaches, but lower river trout reached spawning habitats later than individuals from the middle river. Migration rate had a positive relationship with fork length and mean river discharge. We also found that redband trout made upstream spring migrations as sub‐adults and as adults. Whereas adult trout migrated to spawn, immature individuals migrated to river segments with more favourable thermal conditions. In both cases, migrations occurred where seasonally appropriate or life‐stage‐specific habitat patches for growth, survival, or reproduction were spatially segregated. 相似文献
9.
Migratory behaviour of brown trout, Salmo trutta L: importance of genetic and environmental influences 总被引：1，自引：1，他引：0
I. Näslund 《Ecology of Freshwater Fish》1993,2(2):51-57
Lake Storvindeln in northern Sweden supports a population of fast-growing lake-run brown trout. Spawning and early rearing take place in the River Vindelälven, while most growth occurs in the lake (piscivory). A smaller tributary to the lake, Låktabäcken Creek, holds a resident, early maturing, short-lived brown trout population, although no migratory barriers have existed since 1947. To establish a lake-run trout population, fry from the migratory R. Vindelälven stock were introduced into the creek during 1985–1991. Introduced trout descended to the lake prior to maturing. As a result of the introduction, large adult trout returned from L. Storvindeln to the creek to spawn in 1991 and 1992; i. e., the introduced trout were able to complete a migratory life cycle. Genetic factors appeared to have a primary influence on the predisposition to migrate in this case, and it is suggested that migratory populations rarely develop from strictly resident ones. 相似文献
10.
Abstract Telemetry was used to examine spawning migration of sea trout, Salmo trutta L. (n = 126), in two rivers in northern Sweden. The spawning areas defined by radio‐tagged fish differed between the river systems. In the River Vindelälven, sea trout spawned in the main stem and 80% of tagged individuals returned to areas where hatchery‐reared juveniles had been previously stocked. In the River Piteälven, 74% of tagged sea trout ascended tributaries for spawning. Tagged fish were categorised into three groups of migratory pattern. cart (classification and regression tree) analysis indicated that distance from tagging location to spawning site (Sdist) explained the migratory patterns. Large Sdist separated fish with stepwise upstream migration from those with up‐ and downstream migrations and one‐directional direct migration. Fish tagged early in the season migrated the longest distance to spawning areas. Stocking locations and sex explained the large search behaviour up‐ and downstream in the rivers. The findings are important for the sustainable management of sea trout in the Gulf of Bothnia. 相似文献
11.
Eric B. Taylor Rachel Chudnow Ray Pillipow Ian Spendlow Brett van Poorten 《Fisheries Management and Ecology》2021,28(3):219-229
A mixed-stock fishery occurs when multiple populations of a fish species are exploited together in a common area where they aggregate outside the breeding season (e.g. for feeding or overwintering), and the aggregation is known as a mixture. Recreational fishing often exploits such mixtures, and estimating the proportional contributions of populations to fisheries promotes more sustainable resource use. Ten DNA microsatellites were assayed in a mixture of bull trout Salvelinus confluentus Suckley overwintering in the Nechako River, upper Fraser River, British Columbia, and in baseline population samples from 14 tributaries putatively contributing to the overwintering mixture. A DNA microsatellite-based mixed-stock fishery analysis suggested that five populations together contributed 0.80 to the mixture. Most of the errors associated with the mixture estimates were attributable to uncertainty in baseline allele frequencies. Radiotracking data confirmed that tributary populations contributing to the mixture estimated by genetic analysis also contained individuals that moved between spawning tributaries and overwintering sites. The results better resolve habitat use by potadromous bull trout in the upper Fraser River and, in combination with assessments of baseline population-specific spawning abundances and productivity, will better inform a decision of whether or not allowing some harvest within the current catch-and-release fishery is biologically sustainable. 相似文献
12.
C. M. HORSCH 《Journal of fish diseases》1987,10(6):453-460
Abstract. Whirling disease was diagnosed in steelhead trout, Salmo gairdneri Richardson, during 1985 at Coleman National Fish Hatchery in the Battle Creek drainage of the upper Sacramento River basin, California, USA. Early confirmation of the aetiologic agent, Myxobolus cerebralis Hofer, 1903, was difficult. However, later investigation confirmed the identity of the agent and led to a management decision to destroy the 1985 brood year of steelhead trout at the hatchery. Sentinel fish and collections of feral trout were used to survey Battle Creek watershed to determine the source of infectivity. Feral rainbow trout, Salmo gairdneri Richardson, from South Fork Battle Creek were found to be infected with M. cerebralis and other infected trout were later found at two commercial rainbow trout hatcheries. No reinfection with M. cerebralis has been detected at the Coleman hatchery since ozonation was begun in early 1986. 相似文献
13.
The South Fork Snake River (Idaho, USA) supports a native Yellowstone cutthroat trout (YCT) population Oncorhynchus clarkii bouvieri (Richardson) threatened by non‐native rainbow trout O. mykiss (Walbaum). Electric weirs prevent rainbow trout passage into YCT spawning tributaries but may cause spinal injuries. YCT captured at electric weirs on Palisades and Pine Creeks and a control waterfall‐velocity weir on Burns Creek were X‐rayed in 2012 and 2013 to estimate spinal injury rates. Electrical pulse frequency was increased from 2012 to 2013 at the Palisades (from 11.5 to 20 Hz) and Pine weirs (13–20 Hz), and spinal injury rates were found to increase from 11.3 to 21.3% at Palisades and from 6.5 to 14.7% at Pine, while Burns injury rates remained constant (4.5% in 2012 and 6.0% in 2013), suggesting the electric weirs caused spinal injuries in YCT. Lower pulse frequencies may minimise YCT spinal injury but still prevent rainbow trout from accessing YCT spawning tributaries. 相似文献
14.
Abstract A severe fish kill event caused by agricultural pollution impacted 2.4 km of the River Blackwater, Northern Ireland, in August 2007. A post‐kill monitoring programme sampled existing monitoring sites in the fish kill zone as well as upstream and downstream control sites. Post‐kill monitoring in combination with historical background data facilitated an assessment of the extent and severity of the disturbance episode on local salmonid populations. Subsequent recovery patterns indicated that total salmonid abundance returned to control levels within 1 year. Total salmonid biomass recovered within 2 years, whereas brown trout age structure took up to 3 years to return to background levels. Recovery dynamics were dominated by large‐scale directional migrations rather than random local movements. This included an initial autumnal immigration of 0+ age class brown trout, Salmo trutta L., in late 2007 followed by spawning migrations of adult migratory salmonids. The significance of relatively rapid natural recovery patterns is discussed in the context of potential management options such as restocking. 相似文献
15.
The population dynamics of Atlantic salmon (Salmo salar L.) and brown trout (Salmo trutta L.) were compared in a small tributary of the River Scorff (Brittany, France) from spawning time to the beginning of the third growing season. The spawning and fry emergence of the two species took place at approximately the same time. In the first autumn, the densityof 0+ juveniles and settling rate from the egg stage were much higher in trout than in salmon. The emigration rate from 0+ population was much higher in trout than in salmon. The size of resident and migrating fish was always smaller in salmon than in trout, whatever the age. The low level of salmon production in the brook, compared with trout, was the result of low survival from egg to 0+ stage in autumn, combined with the small proportion of juveniles migrating after the first growing season. This was not compensated by a high number of migrants the next year. The role of physical habitat, inter-and intraspecific competition, predation and migration dependence on size and early sexual maturity is discussed. Indications are that small tributaries of the type studied are of great value for recruitment in trout but not very productive for juvenile salmon. 相似文献
16.
Seasonal changes in spatial patterns of Oncorhynchus mykiss growth require year‐round monitoring 下载免费PDF全文
下载免费PDF全文 Ian A. Tattam Hiram W. Li Guillermo R. Giannico James R. Ruzycki 《Ecology of Freshwater Fish》2017,26(3):434-443
Growth and movement of juvenile salmonids influence the expression of individual life history traits and production of adults at the population scale. We individually marked and recaptured juvenile Oncorhynchus mykiss over the course of a year in Murderers Creek, a semi‐arid tributary to the South Fork John Day River in Northeast Oregon. We tagged O. mykiss in three reaches with differing stream gradient, stream temperature and fish density. Mean growth rates differed significantly among reaches and seasons with a significant interaction between reach and season. Reaches with high growth rates shifted across Murderers Creek among seasons. Stream reaches with high growth during the winter had low growth during summer and vice‐versa. The proportion of individuals moving at the reach scale during summer was low (≤2.6%), suggesting that individuals did not track resources at the reach scale. The spatio‐temporal variation in growth indicates that monitoring stream salmonids across multiple seasons is necessary to accurately characterise the production of different stream reaches. 相似文献
17.
水利设施运行影响下的鱼类早期资源发生规律被逐渐关注,坝下区域也成为鱼类产卵生境的关注热点。西苕溪作为太湖上游的重要补充支流,是太湖流域鱼类完成生活史过程的重要载体。为解析电站影响下的坝下河流生境变量与鱼类早期资源的内在联系,本研究于2022年4—7月在西苕溪江东电站坝下的东山段开展了持续90 d的鱼类早期资源调查以及时空格局研究。结果显示,该区域鱼卵日平均密度为(0.5±0.7)ind/m3,仔鱼日平均密度为(0.5±0.6) ind/m3。运用形态学结合分子生物学方法进行种类鉴定,共鉴定鱼类35种,隶属4目14科22属,其中产沉性卵鱼类9种,产浮性卵5种,产黏性卵9种,产漂流性卵12种。5月下旬、6月上旬和6月下旬为产卵高峰期。左右岸样线以沉性卵和以水生植物为黏附基质的产黏性卵鱼类为主,河心样线则以产漂流性卵、产黏性卵和浮性卵鱼类为主。该区域鱼类卵苗数量受水温、流速、水位影响较大,水位、流速是影响鱼类繁殖的主要因子,电站调度对卵苗量有显著影响。基于卵苗收获量、卵苗发育时期等结果,判定该采样区域——西苕溪江东电站坝下东山段为适宜多种鱼类繁殖的复合型产卵场,对太湖流域鱼类多样性和渔业资源... 相似文献
18.
Abstract Low-head dams in arid regions restrict fish movement and create novel habitats that have complex effects on fish assemblages. The influence of low-head dams and artificial wetlands on fishes in Muddy Creek, a tributary of the Colorado River system in the USA was examined. Upstream, fish assemblages were dominated by native species including two species of conservation concern, bluehead sucker, Catostomus discobolus Cope, and roundtail chub, Gila robusta Baird and Girard. The artificial wetlands contained almost exclusively non-native fathead minnow, Pimephales promelas Rafinesque, and white sucker, Catostomus commersonii (Lacepède). Downstream, fish assemblages were dominated by non-native species. Upstream spawning migrations by non-native white suckers were blocked by dams associated with the wetlands. However, the wetlands do not provide habitat for native fishes and likely inhibit fish movement. The wetlands appear to be a source habitat for non-native fishes and a sink habitat for native fishes. Two non-native species, sand shiner, Notropis stramineus (Cope), and redside shiner, Richardsonius balteatus (Richardson), were present only downstream of the wetlands, suggesting a beneficial role of the wetlands in preventing upstream colonisation by non-native fishes. 相似文献
19.
- 1. The lacustrine brown trout (Salmo trutta) is endangered and of high conservation importance. In the only spawning habitat of the population in the Bavarian Lake Walchensee, the River Obernach, a substantial decrease in spawning runs has been reported. In this study, the present ecological state of the spawning stream was analysed with the objective of identifying life‐stage specific limitations to successful recruitment attributable to deficiencies in (i) spawning migration, (ii) spawning habitat quality, and (iii) habitat quality for juveniles.
- 2. Structural stream analysis showed that discharge and several migration barriers — particularly near the river outlet into the lake — prevent successful spawning migrations at normal water levels. Migration barriers are probably the main limiting factor for reproduction of lacustrine brown trout, whereas structural variability of the Obernach meets the habitat requirements of both spawners and juveniles.
- 3. Spawning site quality was suitable for trout, as indicated by stream substratum texture and high exchange rates between free‐flowing water and the interstitial zone in physico‐chemical parameters (redox potential, dissolved oxygen, pH, temperature and conductivity).
- 4. Analyses of fish community structure revealed dominance of lithophilic species, in particular of riverine brown trout (Salmo trutta). Its density and intact demographic population structure suggest that spawning and juvenile habitat quality for salmonids is not limiting. Recapture of stocked lacustrine trout juveniles also indicates habitat suitability for the juvenile stage.
- 5. In conclusion, the results show that the methodology used in this study is suitable for the identification of life‐stage specific habitat deficiencies in lacustrine brown trout and other fish species. Availability of habitat data throughout the species' distribution range is a first crucial step for the development of an effective recovery plan. Copyright © 2009 John Wiley & Sons, Ltd.
20.
Abstract – We examined the expected changes in the life history trajectory of an Arctic species, broad whitefish, in the lower Mackenzie River between an anadromous population with spawning migrations of 350–450 km and a potamodromous population with spawning migrations of 5–12 km. Based on life history theory we predicted that the anadromous population would have faster growth, later age-at-maturity, and greater reproductive investment than the potamodromous population. Early in its life the anadromous population had faster growth than the potamodromous but later growth was slower. Age-at-maturity was greater in the anadromous population than the potamodromous. Reproductive investment was higher in the anadromous population. We conclude that the broad whitefish did not conclusively follow the pattern of variation observed between migratory and relatively sedentary populations in temperate zones. Fecundity was greater in the migratory population but not conclusively linked to age-at-maturity or growth-rate differences. 相似文献