Zeitschriftenartikel: „Downstream spawning“

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Babcock, Russ, Elke Franke und Neill Barr. „Does spawning depth affect fertilization rates? Experimental data from the sea star Coscinasterias muricata“. Marine and Freshwater Research 51, Nr. 1 (2000): 55. http://dx.doi.org/10.1071/mf98132.

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Measurements of fertilization rates in free-spawning marine invertebrates have shown that reproductive success is related to both behavioural and environmental factors. Water depth has been suggested as being one such factor affecting fertilization success. In experimental spawnings of the sea star Coscinasterias muricata, fertilization rates decreased exponentially with distance from sperm source but were frequently greater than 20% at distances >10 m downstream. Current speed did not have a significant effect on fertilization rate over the range of velocities examined. Fertilization rates directly downstream from spawning individuals were higher in shallow water (<1 m) than in deep water (>5 m). Diffusion models using empirically derived site-dependent diffusion parameters supported these findings but suggested that this would only be true for eggs released directly downstream from a sperm source. Once lateral diffusion of sperm was accounted for, the model predicted little overall difference in fertilization rates for shallow and deep spawners. These results from Coscinasterias indicate that movements into shallow water at the time of spawning, which have been reported in several asteroid species, may provide little reproductive advantage in environments experiencing net flow conditions.

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Sinnatamby, R. Niloshini, Madalena C. Pinto, Fiona D. Johnston, Andrew J. Paul, Craig J. Mushens, Jim D. Stelfox, Hillary G. M. Ward und John R. Post. „Seasonal timing of reproductive migrations in adfluvial bull trout: an assessment of sex, spawning experience, population density, and environmental factors“. Canadian Journal of Fisheries and Aquatic Sciences 75, Nr. 12 (Dezember 2018): 2172–83. http://dx.doi.org/10.1139/cjfas-2017-0542.

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Using individual tags combined with a fish fence operated at the mouth of Smith-Dorrien Creek, the primary spawning habitat for Lower Kananaskis Lake bull trout (Salvelinus confluentus), we approximated a complete census of the spawning population from 1996 to 2000 to assess whether timing of upstream and downstream spawning migrations varied with extrinsic and intrinsic factors. The timing of both upstream and downstream migrations varied with sex, previous spawning experience, density, and temperature. Inferred spawning duration based on the predicted upstream and downstream migration dates indicated that experienced female spawners spent the least amount of time upstream and first-time spawners spent the most time upstream. No consistent differences in upstream migration timing were observed between non-repetitive and repetitive spawners. We suggest that variations in spawning migration timing observed in Lower Kananaskis Lake may be linked to environmental factors that influence upstream swimming ability and acquisition and expenditure of energy with respect to reproduction.

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Brown, Richard S., und William C. Mackay. „Spawning ecology of cutthroat trout (Oncorhynchus clarki) in the Ram River, Alberta“. Canadian Journal of Fisheries and Aquatic Sciences 52, Nr. 5 (01.05.1995): 983–92. http://dx.doi.org/10.1139/f95-097.

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Spawning movements of cutthroat trout (Oncorhynchus clarki) were evaluated using radiotelemetry in a montane river and a headwater tributary. The movements of 23 fish were monitored in spring 1991 and 1992. Fish moved upstream and downstream to spawning areas. These movements fell into two distinct patterns: in one, fish emigrated to tributaries and in the other they traveled to main-stem or side-channel spawning grounds. The pre- and post-spawning movements made by fish that spawned in tributaries were longer than those made by fish that spawned in the main-stem or side-channel areas. While spawning, the fish stayed within 400-m sections of a stream but frequently moved within this area. After spawning, trout moved upstream or downstream to summer rearing habitats where they stayed until observations were ended.

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Castro-Santos, Theodore, und Benjamin H. Letcher. „Modeling migratory energetics of Connecticut River American shad (Alosa sapidissima): implications for the conservation of an iteroparous anadromous fish“. Canadian Journal of Fisheries and Aquatic Sciences 67, Nr. 5 (Mai 2010): 806–30. http://dx.doi.org/10.1139/f10-026.

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We present a simulation model in which individual adult migrant American shad ( Alosa sapidissima ) ascend the Connecticut River and spawn, and survivors return to the marine environment. Our approach synthesizes bioenergetics, reproductive biology, and behavior to estimate the effects of migratory distance and delays incurred at dams on spawning success and survival. We quantified both the magnitude of effects and the consequences of uncertainty in the estimates of input variables. Behavior, physiology, and energetics strongly affected both the distribution of spawning effort and survival to the marine environment. Delays to both upstream and downstream movements had dramatic effects on spawning success, determining total fecundity and spatial extent of spawning. Delays, combined with cues for migratory reversal, also determined the likelihood of survival. Spawning was concentrated in the immediate vicinity of dams and increased with greater migratory distance and delays to downstream migration. More research is needed on reproductive biology, behavior, energetics, and barrier effects to adequately understand the interplay of the various components of this model; it does provide a framework, however, that suggests that provision of upstream passage at dams in the absence of expeditious downstream passage may increase spawning success — but at the expense of reduced iteroparity.

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Acolas, M. L., M. L. Bégout Anras, V. Véron, H. Jourdan, M. R. Sabatié und J. L. Baglinière. „An assessment of the upstream migration and reproductive behaviour of allis shad (Alosa alosa L.) using acoustic tracking“. ICES Journal of Marine Science 61, Nr. 8 (01.01.2004): 1291–304. http://dx.doi.org/10.1016/j.icesjms.2004.07.023.

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Abstract We provide a detailed description of the migratory and reproductive behaviour of allis shad (Alosa alosa L.), a species that is in decline in Europe. Adult swimming behaviour during the last part of upstream migration and on a spawning ground downstream of an insurmountable dam was studied in detail and its main features identified, “characterized” in this context. Mobile telemetry and a fixed telemetry system were used to record fish positions and to monitor 23 acoustically tagged individuals (17 females and six males) during the 2001 and 2002 reproductive seasons. Allis shad showed considerable exploratory behaviour, and a rest area was observed 1.5 km downstream of the spawning ground. Thirteen individuals were observed on the spawning area, though both males and females spent most of their time (70–99%) away from it. Male and female residency times on the spawning area were, respectively, 1–11 days and 1–7 days, and females were observed during both day and night on the spawning ground. In 2002, an analysis of the 3D swimming behaviour on the spawning ground of six individuals allowed us to estimate the number of spawning events per fish. Males participated in more spawning acts (up to 60) than females (0–2).

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Chen, Pan, Lan Li und Hongbin Zhang. „Spatio-temporal variability in the thermal regimes of the Danjiangkou reservoir and its downstream river due to the large water diversion project system in central China“. Hydrology Research 47, Nr. 1 (18.06.2015): 104–27. http://dx.doi.org/10.2166/nh.2015.210.

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Understanding water temperature variation in regulated rivers and reservoirs becomes increasingly important as the environment and ecosystem are approaching their thermal limits. In this paper, a multi-model approach is used to quantitatively access the spatio-temporal change in thermal structures of the Danjiangkou reservoir and its downstream river. The area is subject to thermal and hydrological alterations due to three large water diversion projects and related auxiliary projects, including a project to heighten the Danjiangkou dam and two small downstream reservoirs. It is found that the Danjiangkou dam heightening project alters water temperature seasonally, increasing it in winter and decreasing it in summer; while the three large water diversion projects and the two small downstream reservoirs mitigate the effect. Water temperature change in the downstream river is also studied from the aspects of release temperature and release discharge of the Danjiangkou reservoir. The former mainly changes the water temperature near the dam, while the latter affects the recovery rate and the recuperation distance. Ecological impact of the water temperature change is discussed based on the spawning of fish, indicating that the spawning periods may lag behind and the optimal spawning locations may move downstream.

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Bestgen, Kevin R., Harry J. Crockett, Matthew R. Haworth und Ryan M. Fitzpatrick. „Production of Nonadhesive Eggs by Flathead Chub and Implications for Downstream Transport and Conservation“. Journal of Fish and Wildlife Management 7, Nr. 2 (01.07.2016): 434–43. http://dx.doi.org/10.3996/022016-jfwm-018.

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Abstract Plains stream fishes in North America, including flathead chub Platygobio gracilis, are negatively affected by stream-flow alterations and fragmentation, and limited information on egg type and reproductive strategy hinders their conservation. On the basis of several lines of evidence, including laboratory culture, observations of reproduction in captivity, and capture and rearing of eggs from Fountain Creek, Colorado, we report that flathead chub produce nonadhesive eggs. Flathead chub eggs are relatively small at 2.3 mm mean diameter, have a greater yolk-to-egg volume ratio and thus sink faster, and take longer to hatch, compared with nonadhesive eggs from pelagic spawning species. Flathead chub are also longer lived compared with pelagic spawning species and the wider variety of habitat types they occupy may influence upstream egg retention. Although spawning mode (e.g., pelagic, lithopelagic, other) is incompletely known for flathead chub, habitat needs in terms of flows and reach lengths suitable for reproduction and recruitment may vary with habitat type but may be similar to that for other pelagic spawning species. Accommodating specialized reproductive life histories of fishes, including egg type and transport characteristics, in stream conservation planning may assist with maintaining or enhancing populations of all Great Plains cyprinids, including increasingly rare flathead chub.

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Kantoush, Sameh, Takamasa Suzuki, Yasuhiro Takemon, Kamal El kadi Abderrezzak, Riadh Ata, Tetsuya Sumi und Mohamed Saber. „Numerical study on reservoir sediment management through adding excavated sediment downstream of dams in Japan“. E3S Web of Conferences 40 (2018): 03033. http://dx.doi.org/10.1051/e3sconf/20184003033.

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Dam related issues have become preoccupying, with raising concerns about detrimental environmental impacts and sedimentation in reservoirs. Reduction of the Ayu-fish production is due to increasing turbidity and decreasing coarse sediment supply by dams in the Tenryu River, Japan. The paper summarizes various case studies on excavated sediment supply in Japan and a case of numerical study to evaluate the effect of the supplied sediment on the spawning redds of Ayu-fish in the Tenryu River. Results of numerical simulations show that under the present management scheme of non-supplied sediment from the upstream dams, suitable spawning redds are formed on sandbars at the confluence instead of riffles. However, field surveys indicate that riffles with newly deposited sediment are more suitable for fish spawning.

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Bradford, M. J., und G. C. Taylor. „Individual variation in dispersal behaviour of newly emerged chinook salmon (Oncorhynchus tshawytscha) from the Upper Fraser River, British Columbia“. Canadian Journal of Fisheries and Aquatic Sciences 54, Nr. 7 (01.07.1997): 1585–92. http://dx.doi.org/10.1139/f97-065.

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Immediately after emergence from spawning gravels, fry of stream-type chinook salmon (Oncorhynchus tshawytscha) populations from tributaries of the upper Fraser River, British Columbia, distribute themselves downstream from the spawning areas, throughout the natal stream, and into the Fraser River. We tested the hypothesis that this range in dispersal distances is caused by innate differences in nocturnal migratory tendency among individuals. Using an experimental stream channel, we found repeatable differences in downstream movement behaviour among newly emerged chinook fry. Fish that moved downstream were larger than those that held position in the channel. However, the incidence of downstream movement behaviours decreased over the first 2 weeks after emergence. We propose that the variation among individuals in downstream movement behaviour we observed leads to the dispersal of newly emerged fry throughout all available rearing habitats. Thus, between- and within-population variation in the freshwater life history observed in these populations may be caused by small differences in the behaviour of individuals.

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Chen, Bing Yu, Hui Huang Luo, Qing Rui Yang, Wei Huang und Hui Ling Han. „The Eco-Hydrological Demand Research on Coreiusheterodon Reproduction in the Upper Yangtze River Reserve“. Applied Mechanics and Materials 641-642 (September 2014): 226–31. http://dx.doi.org/10.4028/www.scientific.net/amm.641-642.226.

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The upper Yangtze river rare and endemic national nature reserve was set up to protect the rare and endemic fish. Affected by the cascade development of the downstream reach of the jinsha river, fish habitat in the national nature reserve have been changed significantly, which will affect the reproduction and growth of the fishes.The Coreius heterodon spawning grounds were located in the Main stream of the natural reserve, andits spawning season needs certain overflowing process to lay eggs. This article used the water level and flow data from 1956 to 2012 in the Zhu Tuo stationto analysis the eco-hydrologicaldemand for Coreiusheterodon breeding. and this result can provide the reference for the ecological operation of cascade reservoirs in the downstreamof jinsha river.

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Kaev, A. M., G. N. Dzen, P. S. Sukhonos und I. S. Bobrov. „ESTIMATION OF ABUNDANCE FOR THE MIGRATING JUVENILE PINK SALMON IN THE RIVERS OF SAKHALIN AND ITURUP ISLANDS IN 2019“. Izvestiya TINRO 200 (26.03.2020): 82–100. http://dx.doi.org/10.26428/1606-9919-2020-200-82-100.

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Number of the pink salmon fry migrating downstream from their spawning grounds in the control rivers in 2019 is assessed as 17546.2 . 103 and 14795.7 . 103 ind. for the Dagi and Bolshoi Khuzi Rivers (northeastern Sakhalin), as 89.1 . 103 and 2636.1 . 103 ind. for the Poronai River tributaries — the Kholodny and Orlovka, as 2759.8 . 103 and 21456.0 . 103 ind. for the Lazovaya and Pugachevka Rivers (western coast of the Patience/Terpeniya Bay), as 5803.8 . 103 and 19020.0 . 103 ind. for the Voznesenka and Ochepuha Rivers (southeastern Sakhalin), as 1822.4 . 103 and 2139.0 . 103 for the Taranai and Kura Rivers (Aniva Bay coast), and as 15834.1 . 103 and 7626.1 . 103 ind. for the Rybatskaya and Olya Rivers (Iturup Island), respectively. In all areas, the pink juveniles migrated from the spawning grounds earlier than usual, obviously because of accelerated development of the embryos in conditions of abnormally warm autumn. The number of juveniles migrated from all spawning grounds in the rivers of respective regions is estimated taking into account the escapement of pink salmon spawners and the downstream migration index determined for the control rivers (ratio of the spawners escapement and the number of subsequent downstream migrating juveniles): the total number for the natural spawning grounds is estimated as 1168.9 . 106 ind. for the rivers of the eastern coast of Sakhalin (including the Aniva Bay) and 471.1 . 106 ind. for the rivers of Iturup Island (Okhotsk Sea coast). Additional 141.3 . 106 ind. were released from artificial hatcheries of eastern Sakhalin and 122.0 . 106 ind. — from artificial hatcheries of Iturup Island. The downstream migration is considered as highly abundant for northeastern Sakhalin and Iturup Island, but is insufficiently abundant for the Patience/Terpeniya Bay and Aniva Bay where the landings of this generation should be limited. The pink salmon return to southeastern Sakhalin in 2020 is expected to be better than in 2018 due to satisfactory abundance of the juveniles from natural spawning grounds.

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Fortin, Réjean, Martin Léveillé, Paul Laramée und Yves Mailhot. „Reproduction and year-class strength of the Atlantic tomcod (Microgadus tomcod) in the Sainte-Anne River, at La Pérade, Quebec“. Canadian Journal of Zoology 68, Nr. 7 (01.07.1990): 1350–59. http://dx.doi.org/10.1139/z90-202.

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Experimental catches of a fyke-net fishery operated in the Sainte-Anne River during the 1980–1981 to 1983–1984 spawning seasons showed that although the majority of adult tomcod migrate upstream during rising tide, significant numbers do so against the tidal current. Most spawners return to the Saint Lawrence River during a falling tide. In the first 2 years, peak upstream migration occurred during the second half of December, and in the last 2 years, early in the second half of January. The date of peak upstream migration is significantly correlated with September and October air temperature in the summer habitat. Peak downstream migration of spawned-out adults occurred during the second half of January in 3 years and on 1 February in 1 year. The peak of the upstream and downstream migration of males and females generally occurred on the same dates. The spawning period extends minimally from mid-December to mid-February, but probably peaks close to the maximum of the downstream migration. The length and age composition of the Sainte-Anne River tomcod spawning stock remained relatively stable between the 1980–1981 and the 1983–1984 seasons. For the 1975–1976 to 1981–1982 period, the environmental variable to which year-class strength showed the highest parametric correlation was mean December Sainte-Anne River discharge. Stronger year-classes were produced in years of high water levels and discharge during the spawning period.

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Hinckley, Sarah, Kevin M. Bailey, Susan J. Picquelle, James D. Schumacher und Phyllis J. Stabeno. „Transport, Distribution, and Abundance of Larval and Juvenile Walleye Pollock (Theragra chalcogramma) in the Western Gulf of Alaska“. Canadian Journal of Fisheries and Aquatic Sciences 48, Nr. 1 (01.01.1991): 91–98. http://dx.doi.org/10.1139/f91-013.

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The spawning distribution of walleye pollock (Theragra chalcogramma) and subsequent southwesterly drift of eggs, larvae, and juveniles were investigated in Shelikof Strait, March–September 1987. In mid-March, a hydroacoustics survey found that spawning adults were concentrated in the deeper parts of Shelikof Strait, as were eggs collected in this area during an ichthyoplankton survey about 1 mo later. In May, a concentration of young larvae was found 100–150 km to the southwest of the spawning area. In late June and early July, the center of distribution of late larval and early juvenile walleye pollock was further to the southwest, between the Shumagin and Semidi Islands. By August and September, juveniles were mostly distributed downstream of the Shumagin Islands. The rate of drift of eggs and larvae through June was estimated at 4–6 cm/s. The trajectories of satellite-tracked buoys deployed in the region of greatest egg abundance revealed similar patterns to those of the early life stages of walleye pollock. These observations demonstrate that transport is an important factor determining the distribution of pollock larvae in downstream coastal nursery areas.

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Beer, W. Nicholas, und James J. Anderson. „Effect of spawning day and temperature on salmon emergence: interpretations of a growth model for Methow River chinook“. Canadian Journal of Fisheries and Aquatic Sciences 58, Nr. 5 (01.05.2001): 943–49. http://dx.doi.org/10.1139/f01-049.

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A mechanistic temperature-dependent model for preemergent growth coupled with spawning and river temperature data is used to evaluate early life history strategies for chinook salmon (Oncorhynchus tshawytscha) in the Methow River, Washington, U.S.A. Since the model provides a predictable coupling between time of spawning and fry emergence, it helps explain the spatial and temporal patterns observed for the sympatric stocks. The model suggests that progeny of August-spawning chinook in upper river habitats emerge at button-up (no visible yolk sac) over a wide range of days in the early spring. The eggs grow efficiently, which maximizes fry mass. The progeny of October-spawning downstream chinook can exploit a wide range of habitats in the river because their emergence mass is not sensitive to location in the river, but the adults must spawn later in the season to avoid summer high temperatures. Late spawning forces fry to emerge prior to button-up to avoid scouring flows but synchronizes their emergence times. The trade-offs between the spawning strategies of these two salmon runs are complex and the seasonal and spatial distribution of temperatures plays a critical role in these trade-offs.

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Heggberget, Tor G., Lars P. Hansen und Tor F. Næsje. „Within-River Spawning Migration of Atlantic Salmon (Salmo salar)“. Canadian Journal of Fisheries and Aquatic Sciences 45, Nr. 10 (01.10.1988): 1691–98. http://dx.doi.org/10.1139/f88-200.

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The migration pattern of adult spawners of Atlantic salmon (Salmo salar) in two Norwegian streams was analysed by ultrasonic and mechanical tagging to investigate within-river migration. Salmon were tagged in the estuary as they approached the river before spawning. They displayed a systematic and directional upstream pattern of movement in the river. Seventy-one percent of the fish transplanted 6 km downstream from the capture site about 2 mo before spawning returned to the donor area. Fish transported 7 km upstream from the capture site exhibited a low degree of backtracking to the donor site (one of seven fish). Mechanical tagging of salmon on spawning grounds showed that both male and female spawners released 150 and 600 m upstream from the spawning area were able to return to the original site of spawning with a mean precision of 87%. In both streams, the migration pattern and the return to original site of capture support the hypothesis of local homing of Atlantic salmon, although some fish stray to other areas of the stream.

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Dębowski, Piotr, Rafał Bernaś, Michał Skóra und Jacek Morzuch. „Mortality of silver eel (Anguilla anguilla) migrating downstream through a small hydroelectric plant on the Drawa River in northern Poland“. Archives of Polish Fisheries 24, Nr. 2 (01.06.2016): 69–75. http://dx.doi.org/10.1515/aopf-2016-0008.

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Abstract The European eel, Anguilla anguilla L., is an endangered species. Barriers to its downstream spawning migration are one of the greatest threats this species faces. There are hundreds of hydroelectric plants (HEP) on rivers in Poland (> 600), and thousands throughout Europe. Eel that pass through HEP turbines as they migrate downstream suffer high mortality, but this depends mainly on local and technical conditions. Silver eel mortality was estimated and the possibility of the fish bypassing the turbines was studied between November 2013 and June 2014 at a typical HEP in northern Poland. Two telemetry methods were used with 49 eel: passive integrated transponder (PIT) system and acoustic telemetry. Fifty five percent of eel migrated downstream in fall 2013, soon after their release, and 45% migrated the next spring. The eel did not use the fish passes designed for upstream migration; thus, they were forced to go through the turbines, which resulted in 55% mortality. HEPs cause interruptions and delays in eel spawning migrations and are responsible for high eel mortality. This can make implementing an eel restitution plan difficult or even impossible in river systems with many barriers.

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Duong, Thuy Yen, Kim T. Scribner, James A. Crossman, Patrick S. Forsythe und Edward A. Baker. „Environmental and maternal effects on embryonic and larval developmental time until dispersal of lake sturgeon (Acipenser fulvescens)“. Canadian Journal of Fisheries and Aquatic Sciences 68, Nr. 4 (April 2011): 643–54. http://dx.doi.org/10.1139/f2011-008.

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For migratory fish like lake sturgeon ( Acipenser fulvescens ), the period from egg deposition through embryonic and larval development until dispersal (ELDTUD) contributes substantially to variation in survival at the individual level and to population levels of recruitment. Using genetically determined parentage, we examined the relative importance of environmental variables in a stream environment (e.g., temperature and discharge) and maternal effects (including individual female body size, spawning time, and location) to ELDTUD on an individual basis. Adult lake sturgeon (n = 208) spawning in the Upper Black River (Michigan, USA), and larvae (n = 1444) dispersing downstream were captured during the 2007 spawning season. We used generalized mixed models and multimodel inference based on Kullback–Leibler information-theoretic criteria to demonstrate that environmental variables and the maternal effects of individual female and spawning time were both important predictors of ELDTUD. Decreasing ELDTUD during the season resulted from linearly increasing temperature and nonlinearly decreasing river discharge. Spawning time and individual female explained a large proportion of variation in ELDTUD. The individual-based approach used in this study provided precise estimates of ELDTUD and also facilitated the partitioning of variation in ELDTUD of larvae produced by the same female and among females spawning at different times and different environmental conditions.

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Warrillow, J. A., D. C. Josephson, W. D. Youngs und C. C. Krueger. „Differences in sexual maturity and fall emigration between diploid and triploid brook trout (Salvelinus fontinalis) in an Adirondack lake“. Canadian Journal of Fisheries and Aquatic Sciences 54, Nr. 8 (01.08.1997): 1808–12. http://dx.doi.org/10.1139/f97-087.

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High levels of emigration coincident with maturity and spawning have been reported from brook trout (Salvelinus fontinalis) populations in Adirondack lakes. These lakes typically had few spawning areas and required stocking to maintain populations. We compared diploid and triploid brook trout to identify differences in gonadal development and emigration. Age 1 + and 2 + diploid and triploid brook trout held in captivity were examined internally for gonadal development. More diploid trout were mature than triploid fish (p < 0.01). Of triploid brook trout that matured, all were males. Yearling diploid and triploid brook trout were also stocked into a lake that had an outlet but no spawning areas. During the fall spawning season, only mature yearling triploid males, diploid males, and diploid females were caught in an outlet trap. No triploid females were caught. A greater proportion of diploids emigrated than triploids (p < 0.01). Triploidy in females arrested emigration by preventing sexual maturation. Triploid male brook trout should not be stocked because they can pose a reproductive risk to wild brook trout downstream from lakes. Stocking triploid females could reducefall emigration and thus reduce the loss of catchable brook trout from Adirondack lakes with outlets and little spawning habitat.

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Gresswell, Bob, und Kris Homel. „Evaluating the Movement Patterns of Snake River Finespotted Cutthroat Trout in the Snake River Below Jackson Lake Dam, Grand Teton National Park“. UW National Parks Service Research Station Annual Reports 31 (01.01.2008): 23–28. http://dx.doi.org/10.13001/uwnpsrc.2008.3693.

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The Snake River finespotted cutthroat trout Oncorhynchus clarkii behnkei has been formally recognized as a subspecies of cutthroat trout Oncorhynchus clarkii, but it is more generally perceived as a morphologically divergent ecotype of the more broadly distributed Yellowstone cutthroat trout Oncorhynchus clarkii bouvieri. This large-river cutthroat trout has persisted in the Snake River downstream of Jackson Lake Dam through a century of flow regulation. Although there is a popular sport fishery focused on this native trout, spawning and distribution patterns throughout its range are poorly understood. Consequently, it is difficult to predict how future disturbances (e.g., climate change or an increase in the prevalence of nonnative species) may affect behavior or persistence. In 2008, radio telemetry techniques were used to identify spawning patterns of cutthroat trout. From August-October, 2007, 49 radio telemetry tags were implanted into cutthroat trout in the Snake River, Grand Teton National Park and fish movements were tracked during the spawning season. Significant temporal and spatial variability in spawning behavior was observed (n = 22 fish with distinct spawning migrations). The earliest spawning migration began at the end of April, and the last spawning migration was initiated in mid-July. Spawning was observed in the mainstem and side channels of the Snake River, several tributaries, and three major spring creek complexes. Although the majority of this spawning activity occurred within 40 km of the respective original tagging location, three fish migrated to spawning areas 75-100 river kilometers away. Ultimately, developing a comprehensive understanding of the behavioral variability of Snake River finespotted cutthroat trout and the habitat connectivity required to complete the life cycle will provide new insights into the management of this portion of the Snake River.

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Koster, W. M., D. R. Dawson, J. R. Morrongiello und D. A. Crook. „Spawning season movements of Macquarie perch (Macquaria australasica) in the Yarra River, Victoria“. Australian Journal of Zoology 61, Nr. 5 (2013): 386. http://dx.doi.org/10.1071/zo13054.

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The Macquarie perch (Macquaria australasica) is a threatened fish species that inhabits rivers and impoundments in south-eastern Australia. Previous studies have shown that Macquarie perch in impoundments exhibit synchronised upstream spawning migrations to shallow, fast-flowing habitats in the lower reaches of inflowing streams. There has been little study of movement behaviours of entirely riverine populations of Macquarie perch despite this being the species’ natural habitat. Here, radio-telemetry is used to test the hypothesis that riverine populations exhibit synchronised migrations during the spawning season. Thirty Macquarie perch in the Yarra River, Victoria, a translocated population outside of the species’ natural range, were radio-tagged before the late spring–early summer spawning season and their movements followed over a 10-month period (May 2011 to February 2012). Tagged fish typically occupied restricted reaches of stream (<450 m). Sixteen of the fish undertook occasional upstream or downstream movements (~250–1000 m) away from their usual locations, particularly associated with large flow variations during the spawning season. There was no evidence of synchronised migratory behaviour or movement of multiple fish to specific locations or habitats during the spawning season. Whilst further research over more years is needed to comprehensively document the spawning-related behaviours of riverine Macquarie perch, our study demonstrates that management of riverine populations of this threatened species cannot necessarily be based on the model of spawning behaviour developed for lacustrine populations.

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Harper, Ken C., Frank Harris, Steve J. Miller, John M. Thalhauser und Scott D. Ayers. „Life History Traits of Adult Broad Whitefish and Humpback Whitefish“. Journal of Fish and Wildlife Management 3, Nr. 1 (01.06.2012): 56–75. http://dx.doi.org/10.3996/022011-jfwm-011.

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Abstract Broad whitefish Coregonus nasus and humpback whitefish C. pidschian are important to the regional subsistence economy of the Kuskokwim River watershed, Alaska, where they and other whitefish constitute greater than half of the nonsalmon fish harvests. Harvest occurs year-round from lakes, ponds, and the mainstem by subsistence fishermen and through a limited number of commercial permits. Little is known about the life history (e.g., migration patterns) of these species, and subsistence fishers have raised concerns about declining body size and abundance. Project objectives were to 1) characterize annual movement patterns of mature broad whitefish and humpback whitefish, 2) verify suspected spawning locations and locate new spawning locations for broad whitefish and humpback whitefish, 3) describe overwintering locations for broad whitefish and humpback whitefish, 4) characterize age and length at maturity for broad whitefish and humpback whitefish, and 5) characterize the habitat of at least one humpback whitefish spawning area. During 2006–2009, we implanted radiotransmitters in 135 mature broad whitefish and 83 humpback whitefish and tracked movements in the Kuskokwim River drainage. We identified two mainstem spawning areas used by broad whitefish and three tributary spawning areas and one mainstem spawning area used by humpback whitefish. Broad whitefish continued to move into spawning areas under the ice and spawned in late October or early November. Humpback whitefish spawned in early October before the river froze over. Individuals of each species migrated as far as 800 river kilometers to spawning areas. Both species migrated downstream after spawning, overwintered in the mainstem Kuskokwim River, and exhibited fidelity to oxbow and tundra lake feeding areas in the summer. Consecutive year spawning was exhibited by individuals of both species and occurred more frequently in males than females for broad whitefish. The median age (5 y) of broad whitefish captured for radiotagging was younger than ages observed in samples collected from other broad whitefish populations in Alaska and Canada. Only mature humpback whitefish in spawning condition were found during October in suspected spawning areas in the Holitna and Swift rivers.

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Harding, D. J., D. T. Roberts, D. Sternberg, T. M. Mullins, M. J. Kennard und R. G. Dwyer. „Flow-related migration, juvenile dispersal and gonad development in two co-occurring mullet species, Mugil cephalus and Trachystoma petardi, in a regulated river system“. Marine and Freshwater Research 70, Nr. 8 (2019): 1105. http://dx.doi.org/10.1071/mf18365.

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Catadromous fish species often use elevated flows to migrate from freshwater to downstream spawning grounds. However, in regulated river systems, artificial barriers and flow alteration can disrupt movement cues, affecting fish migration. Using a combination of acoustic telemetry, passive integrated transponder (PIT) tags and gonad maturity data, we assessed the migratory timing and flow requirements for downstream spawning migrations and upstream dispersal in two co-occurring mullet species in the Logan River, eastern Australia. Over 4 years, 141 adult sea mullet (Mugil cephalus) and 28 adult pinkeye mullet (Trachystoma petardi) were implanted with acoustic transmitters and broad-scale movements tracked using an array of 49 acoustic receivers. Juvenile upstream dispersal was monitored using implanted PIT tags and readers deployed in weir fishways. Sea mullet and pinkeye mullet undertook large-scale downstream migrations from February to March. Movements past weirs only occurred once sufficient flow had occurred and, in the case of pinkeye mullet, when gonads were mature. In contrast, juvenile dispersal into upstream habitats occurred primarily between November and April on low flows. This study advances our understanding of bidirectional movement ecology and flow requirements of two co-occurring mullet species to inform environmental flow management (e.g. to facilitate fish passage) in a regulated river system.

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Nyqvist, D., O. Calles, E. Bergman, A. Hagelin und L. A. Greenberg. „Post-Spawning Survival and Downstream Passage of Landlocked Atlantic Salmon (Salmo salar ) in a Regulated River: Is There Potential for Repeat Spawning?“ River Research and Applications 32, Nr. 5 (19.06.2015): 1008–17. http://dx.doi.org/10.1002/rra.2926.

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Merz, Joseph E., Jose D. Setka, Gregory B. Pasternack und Joseph M. Wheaton. „Predicting benefits of spawning-habitat rehabilitation to salmonid (Oncorhynchus spp.) fry production in a regulated California river“. Canadian Journal of Fisheries and Aquatic Sciences 61, Nr. 8 (01.08.2004): 1433–46. http://dx.doi.org/10.1139/f04-077.

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We tested the hypothesis that spawning-bed enhancement increases survival and growth of chinook salmon (Oncorhynchus tshawytscha) embryos in a regulated California stream with a gravel deficit. We also examined how 12 physical parameters correlated within spawning sites and how well they predicted survival and growth of chinook salmon and steelhead (Oncorhynchus mykiss) embryos. Salmon embryos planted in enhanced gravels had higher rates of survival to the swim-up stage than embryos planted in unenhanced spawning gravels. No significant increase in growth was observed. Intergravel temperature and substrate size were strongly correlated with distance downstream from the lowest nonpassable dam. Intergravel turbidity and total suspended and volatile solids were also strongly correlated. Multiple-regression models were built with a combination of physical measurements to predict survival and length of salmon and steelhead embryos. Survival models accounted for 87% of the variation around the mean for salmon and 82% for steelhead. Growth models accounted for 95% of the variation around the mean for salmon and 89% for steelhead. These findings suggest that spawning-bed enhancement can improve embryo survival in degraded habitat. Additionally, measurements of a suite of physical parameters before and after spawning-bed manipulation can accurately predict benefits to target species.

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Goto, Akira. „Reproductive Behavior and Homing after Downstream Spawning Migration in the River Sculpin, Cottus hangiongensis“. Ichthyological Research 34, Nr. 4 (Januar 1988): 488–96. http://dx.doi.org/10.1007/bf02905655.

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MacDonald, D. D., und L. E. McDonald. „The Influence of Surface Coal Mining on Potential Salmonid Spawning Habitat in the Fording River, British Columbia“. Water Quality Research Journal 22, Nr. 4 (01.11.1987): 584–95. http://dx.doi.org/10.2166/wqrj.1987.047.

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Abstract A total of six sites, with similar physical and hydraulic characteristics, located upstream and downstream of the Fording Coal Ltd. mining operation were selected to assess the Influence of mining activities on the quality of stream-bed substrates. The particle size distributions of gravel-bed materials in the Fording River were described using substrate statistics commonly found in the literature. Statistically significant differences (p < 0.001) between upstream (control) and downstream sites were detected in the percentage of sediments smaller than 2.00 mm and 6.35 mm. The differences between upstream and downstream sites were also statistically significant (p < 0.005) for the variables geometric mean particle diameter and Fredle Index. Differences between areas were evident for both sampling periods (September 1985 and April 1986). The biological significance of these differences in stream-bed composition was examined using empirically derived egg to fry survival models for salmonids currently available in the literature. The preliminary results of this study suggest that activities associated with coal mining can increase the content of fine sediment in stream-bed substrates, and thereby compromise the production of salmonids when stream reaches downstream of the development are used as spawning habitats.

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Usvyatsov, Sima, Jeffrey Picka, Ryan Scott Hardy, Travis Dawson Shepherd, James Watmough und Matthew Kenneth Litvak. „Modeling the timing of spawning and hatching of shortnose sturgeon, Acipenser brevirostrum, in the Saint John River, New Brunswick, Canada“. Canadian Journal of Fisheries and Aquatic Sciences 69, Nr. 8 (August 2012): 1316–28. http://dx.doi.org/10.1139/f2012-062.

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Timing of spawning and hatching of shortnose sturgeon, Acipenser brevirostrum , in the Saint John River, New Brunswick, Canada, was estimated using inverse prediction. We examined egg incubation periods at 5, 9, and 13 °C to back-calculate spawning dates. No larvae hatched at 5 °C. At 9 and 13 °C, hatching began after 18 and 8 days post fertilization, respectively. Lengths of yolk-sac larvae reared in the laboratory at 13–21 °C were used to develop a temperature-mediated Gompertz growth model. The inverted Gompertz model, predicting larval age from larval size and water temperature, was applied to 671, 164, and 746 larvae captured in the wild in 2008, 2009, and 2010, respectively. Estimated hatching distributions peaked in late May, and mean spawning events were predicted to occur in late April – early May (9 °C scenario) and middle to late May (13 °C scenario). Larval ages at the two sampling transects, 4.5 km apart, were similar, while catch per unit effort was lower downstream, indicating mortality during dispersal. Inverse prediction of larval ages provides fast and cost-effective estimates of the timing of spawning, hatching, and larval migration in the wild.

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Burger, Carl V., Richard L. Wilmot und David B. Wangaard. „Comparison of Spawning Areas and Times for Two Runs of Chinook Salmon (Oncorhynchus tshawytscha) in the Kenai River, Alaska“. Canadian Journal of Fisheries and Aquatic Sciences 42, Nr. 4 (01.04.1985): 693–700. http://dx.doi.org/10.1139/f85-089.

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From 1979 to 1982,188 chinook salmon (Oncorhynchus tshawytscha) were tagged with radio transmitters to locate spawning areas in the glacial Kenai River, southcentral Alaska. Results confirmed that an early run entered the river in May and June and spawned in tributaries, and a late run entered the river from late June through August and spawned in the main stem. Spawning peaked during August in tributaries influenced by lakes, but during July in other tributaries. Lakes may have increased fall and winter temperatures of downstream waters, enabling successful reproduction for later spawning fish within these tributaries. This hypothesis assumes that hatching and emergence can be completed in a shorter time in lake-influenced waters. The time of upstream migration and spawning (mid- to late August) of the late run is unique among chinook stocks in Cook Inlet. This behavior may have developed only because two large lakes (Kenai and Skilak) directly influence the main-stem Kenai River. If run timing is genetically controlled, and if the various components of the two runs are isolated stocks that have adapted to predictable stream temperatures, there are implications for stock transplantation programs and for any activities of man that alter stream temperatures.

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Tallman, Ross F., und Michael C. Healey. „Phenotypic Differentiation in Seasonal Ecotypes of Chum Salmon, Oncorhynchus keta“. Canadian Journal of Fisheries and Aquatic Sciences 48, Nr. 4 (01.04.1991): 661–71. http://dx.doi.org/10.1139/f91-083.

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We compared the reproductive environments and phenotypes of early and late season breeding stocks of chum salmon, Oncorhynchus keta, to test the hypothesis that seasonal separation has resulted in phenotypically distinct forms. These were autumn- and winter-spawning populations from Bush Creek (Vancouver Island, B.C.) and a winter-spawning stock from nearby Walker Creek. All stocks had a similar time of downstream migration of the fry. No differences were found among the Walker Creek and the autumn-spawning stock of Bush Creek in age at maturity, length composition of spawners, egg size, vertebral counts of adults and fry, and time of fry migration. The winter-spawning stock of Bush Creek differed from the other stocks in egg size and vertebral counts. Discriminant analysis of 10 morphological features of the fry revealed considerable overlap in body form among the stocks. These results do not support the hypothesis that distinct life history morphs are associated with the season of reproduction. We propose that the large amount of similarity in terms of morphology and seasonality among the populations may be the product of selection. Genetic divergence may have occurred to compensate for the environmental differences experienced during embryonic development.

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Broadhurst, B. T., B. C. Ebner, M. Lintermans, J. D. Thiem und R. C. Clear. „Jailbreak: a fishway releases the endangered Macquarie perch from confinement below an anthropogenic barrier“. Marine and Freshwater Research 64, Nr. 9 (2013): 900. http://dx.doi.org/10.1071/mf12245.

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Management interventions are often needed to facilitate the recovery of ecosystems affected as a result of human alteration. Population-level monitoring is often central to evaluating the effectiveness of specific on-ground actions. In the present study, we assessed the response of a remnant population of the endangered Macquarie perch (Macquaria australasica) to the construction of a rock ramp fishway on the Cotter River, Australia, over a 7-year period. Prior to fishway construction, this obligate riverine spawner had been previously confined to Cotter Reservoir and six kilometres of stream by a raised road-crossing. Surveys conducted in the 2 years following fishway completion failed to detect Macquarie perch upstream of the fishway. Subsequent surveys (6–7 years post-fishway completion) detected Macquarie perch up to 12 km upstream of the fishway. The number and distribution of smaller-sized individuals (0+ (<100-mm total length (TL) and 1+ (100- to >150-mm TL)) suggests that individuals found upstream of the fishway are resident stream fish and not fish that have migrated from known downstream spawning areas. The success of the fishway has been timely because enlargement of a downstream reservoir will inundate four kilometres of river and destroy the majority of spawning sites of this species downstream of the fishway in the Cotter River.

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Young, Jeffery L., Scott G. Hinch, Steven J. Cooke, Glenn T. Crossin, David A. Patterson, Anthony P. Farrell, Glen Van Der Kraak et al. „Physiological and energetic correlates of en route mortality for abnormally early migrating adult sockeye salmon (Oncorhynchus nerka) in the Thompson River, British Columbia“. Canadian Journal of Fisheries and Aquatic Sciences 63, Nr. 5 (01.05.2006): 1067–77. http://dx.doi.org/10.1139/f06-014.

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Since 1995, large segments of the late-run sockeye salmon (Oncorhynchus nerka) stock complex from the Fraser River, British Columbia, Canada, have been initiating spawning migrations several weeks earlier than normal. Most aberrant migrants die before spawning. To evaluate the mechanisms underlying the mortality, we intercepted late-run sockeye salmon of the AdamsShuswap stock complex halfway along their freshwater migration (i.e., in the Thompson River Canyon situated 270 km from the Fraser estuary), nonlethally assessed physiological and energetic status, and tracked individuals using gastrically inserted radio transmitters. Aberrant migrants that resumed their migration but failed to reach the spawning grounds had lower gross somatic energy, higher average migration ground speeds, higher plasma osmolality, and higher levels of plasma reproductive hormones than those that reached the spawning grounds. Fish surgically fitted with electromyogram radio transmitters did not continue their migration and fell downstream. These fish displayed excessive bleeding during transmitter implantation, an unusual phenomenon that likely contributed to the fish's inability to resume migration. Blood clotting time decreased steadily throughout the migration period. Collectively, these data implicate a combination of energy depletion, premature reproductive development, and blood loss from wounds as potential contributors to mortality in early migrating late-run sockeye.

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Koster, W. M., D. R. Dawson und D. A. Crook. „Downstream spawning migration by the amphidromous Australian grayling (Prototroctes maraena) in a coastal river in south-eastern Australia“. Marine and Freshwater Research 64, Nr. 1 (2013): 31. http://dx.doi.org/10.1071/mf12196.

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Understanding the reasons and cues for migration is crucial for developing effective conservation and management strategies of diadromous fishes. Spawning and movement patterns of the threatened diadromous Australian grayling (Prototroctes maraena) were investigated in the Bunyip River, Victoria, using drift sampling (2008–2011) and acoustic telemetry (2009–2010) during the autumn–winter spawning period of each year. Fifty-five adult fish (2009: n = 21; 2010: n = 34) were tagged and released in February ~15–30 km upstream of the Bunyip River estuary. Thirteen fish (2009: n = 7; 2010: n = 6) undertook rapid downstream migrations from March to April to reaches immediately upstream of the estuary. Drifting eggs were detected at multiple sites between April and July; however, the majority (78.8%) were collected in the lower reaches within ~0.5 km of the estuary in early–mid-May. Tagged adult fish arrived in this area 1–4 weeks before eggs were detected and usually moved back upstream within 2 weeks following the peak egg abundance. Downstream migration and peak egg abundance were associated with increased river flows. Although the proportion of fish that undertook migrations was low, low rates of tag retention in this species likely account for the failure to detect migration by many of the tagged individuals.

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Quellet, Patrick, und Julian J. Dodson. „Dispersion and Retention of Anadromous Rainbow Smelt (Osmerus mordax) Larvae in the Middle Estuary of the St. Lawrence River“. Canadian Journal of Fisheries and Aquatic Sciences 42, Nr. 2 (01.02.1985): 332–41. http://dx.doi.org/10.1139/f85-042.

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The vertical and horizontal distribution of anadromous rainbow smelt (Osmerus mordax) larvae from hatching in their natal river to their occupation of nursery areas in the middle estuary of the St. Lawrence River was documented to describe the mechanism responsible for the retention of smelt larvae in this area. Peaks of larval abundance observed downstream of the spawning grounds indicate a 24-h periodicity in hatching and the introduction of larvae into the riverine circulation. No retention of larvae was observed between the spawning ground and the downstream portion of the natal river. Our evidence indicates daytime accumulation of larvae at the mouth of the natal river, possibly resulting from the negative phototaxis exhibited by small smelt larvae. Patches of smelt larvae were incorporated into the St. Lawrence estuarine water mass once every 24 h at night following high tide. The subsequent downstream transport of larvae in the St. Lawrence estuary appears slower than the advection of the water mass due to the tendency of larvae to remain deeper in the water column during ebb tides and to concentrate near the surface during flood tides. Smelt larvae are transported from the south shore to the partially mixed northern portion of the middle estuary which represents the principal zone of larval smelt accumulation. We propose that the vertical displacements exhibited by smelt larvae in combination with the two-layer circulation system of the northern middle estuary results in the retention of smelt larvae in this region.

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Larson, Douglas L., Jacob G. Kimmel, Joseph J. Riedy, Jonathan Hegna, Edward A. Baker und Kim T. Scribner. „Male lake sturgeon (Acipenser fulvescens) migratory and spawning behaviors are associated with sperm quality and reproductive success“. Canadian Journal of Fisheries and Aquatic Sciences 77, Nr. 12 (Dezember 2020): 1943–59. http://dx.doi.org/10.1139/cjfas-2020-0124.

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Intra-annual reproductive investments may not be predictive of male reproductive success because of the effects of intra- and intersexual interactions on sperm depletion. For long-lived iteroparous fish species such as lake sturgeon (Acipenser fulvescens), reproductive effort may affect lifetime reproductive success. Radio frequency identification antennas were placed at the mouth of the Upper Black River, Michigan, and downstream of spawning locations to quantify male migratory and mating behaviors, including upstream migration time (UT), river residence time (RT), number of intra-annual spawning migrations (IM), interannual spawning interval, and operational sex ratio during 2017–2018. Computer assisted sperm analysis was used to quantify sperm quality. RT had a strong negative influence on sperm concentration and with measures of sperm quality. RT and the number of females encountered were positively associated with male reproductive success (number of offspring sired) across years. RT, IM, and UT were negatively associated with sperm quality, indicating sperm depletion is a reliable measure of sexual activity. Results demonstrate trade-offs between benefits and costs associated with current reproductive effort on future reproduction.

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Acolas, M. L., V. Véron, H. Jourdan, M. L. Bégout, M. R. Sabatié und J. L. Baglinière. „Upstream migration and reproductive patterns of a population of allis shad in a small river (L'Aulne, Brittany, France)“. ICES Journal of Marine Science 63, Nr. 3 (01.01.2006): 476–84. http://dx.doi.org/10.1016/j.icesjms.2005.05.022.

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Abstract The characteristics and activity of adult allis shad [Alosa alosa (L.)] were analysed during the last part of their upstream migration in the L'Aulne, a small river in Brittany, and during reproduction on a unique spawning ground downstream of an insurmountable dam. The age of the spawners ranged from three to seven years, females being larger and older than males. Population-level migration and reproduction were studied by counting the number of migrating fish, by estimating the sex ratio, and by counting the number of nocturnal spawning acts for three consecutive years starting in 2000. The influence of the environment, especially water temperature and discharge, was highlighted: temperature during migration may supplant the influence of water flow, although high flow could allow passage over the dam. Such factors partly explain the annual pattern of migration and reproduction during the spawning season. The study showed that the biological features and characteristics of this population of allis shad in a small river were similar to those of western Atlantic stocks in large rivers.

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Crook, David A., Wayne M. Koster, Jed I. Macdonald, Simon J. Nicol, Chris A. Belcher, David R. Dawson, Damien J. O'Mahony, Danny Lovett, Adam Walker und Lucas Bannam. „Catadromous migrations by female tupong (Pseudaphritis urvillii) in coastal streams in Victoria, Australia“. Marine and Freshwater Research 61, Nr. 4 (2010): 474. http://dx.doi.org/10.1071/mf09170.

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Understanding migratory requirements is critical for the conservation of diadromous fishes. Tupong (Pseudaphritis urvillii) are diadromous fishes found in freshwater and estuarine regions of south-eastern Australia. Previous studies have hypothesised that mature female tupong undertake downstream spawning migrations from freshwater to the estuary or sea, with a compensatory return of juveniles, and possibly spent fish, back upstream. We applied acoustic telemetry to test this hypothesis. We tagged 55 female tupong in two river systems in Victoria, Australia, and tracked movements for 4- to 6-month periods over 2 years. Thirty-one fish undertook rapid downstream migrations and then appeared to move through the estuary and out to sea between May and August in each year. Migration was associated with relatively high river discharges, and movement from the estuary to the sea tended to occur most frequently during intermediate moon phases. Low rates of movement between September and April suggested that tupong inhabited restricted home ranges outside of the spawning season. The apparently disparate migratory patterns of female (catadromous) and male (non-diadromous) tupong are rare amongst fishes globally. Differential exertion of a range of selective pressures may have resulted in the evolution of sexual differences in migratory modes in this species.

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Schrank, Amy J., und Frank J. Rahel. „Movement patterns in inland cutthroat trout (Oncorhynchus clarki utah): management and conservation implications“. Canadian Journal of Fisheries and Aquatic Sciences 61, Nr. 8 (01.08.2004): 1528–37. http://dx.doi.org/10.1139/f04-097.

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Knowledge of movement patterns is critical to the management and conservation of inland salmonids. We studied the movements of Bonneville cutthroat trout (Oncorhynchus clarki utah) in a drainage in western Wyoming, USA. Our objectives were to (i) characterize the postspawning movement patterns of adult Bonneville cutthroat trout, (ii) contrast postspawning and summer movement patterns, and (iii) identify factors that disrupt the movements of Bonneville cutthroat trout. Our data showed that postspawning movements of Bonneville cutthroat trout formed a continuum, with fish moving from 0.5 to 82.0 km. Postspawning distance was positively related to fish length. Despite the wide range of movement observed during the spring, fish did not move more than 0.5 km during the summer. A road culvert and an irrigation diversion dam did not seem to pose barriers to the upstream movement of Bonneville cutthroat trout to headwater spawning areas in the spring. However, 23% of radio-tagged fish in 2000 moved into the irrigation diversion ditch as they moved downstream after spawning and subsequently died there. Maintaining drainage connectivity is an important conservation concern for trout populations such as this one, where fish move between complementary spawning and summer habitats.

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Parsley, Michael J., Lance G. Beckman und George T. McCabe. „Spawning and Rearing Habitat Use by White Sturgeons in the Columbia River Downstream from McNary Dam“. Transactions of the American Fisheries Society 122, Nr. 2 (März 1993): 217–27. http://dx.doi.org/10.1577/1548-8659(1993)122<0217:sarhub>2.3.co;2.

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Voicu, Răzvan, Artur Radecki-Pawlik, Liliana Voicu, Joseph Dominick Urbani und Doru Bănăduc. „Innovative On-Site Adapted System for Fish Migration with Flow Divider and Glass Collector Basin“. Transylvanian Review of Systematical and Ecological Research 22, Nr. 1 (01.04.2020): 81–98. http://dx.doi.org/10.2478/trser-2020-0006.

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Abstract The authors designed a new site-adapted fish passage system for upstream and downstream migration of small and large fish on the urban sector of the Bistriţa River. The longitudinal connectivity of this lotic system is interrupted by numerous transversal hydrotechnical works (weirs). This proposed system was designed to facilitate fish migration, promote fish recolonization of upstream and downstream habitats, allow the expansion of fish range, and increase spawning potential. All components of the proposed system are attached to a concrete girder located to the right stream bank, except a glass basin that is submerged in the riverbed. The positioning of the system in this girder ensures its resistance to high water events, while offering safe passage for fish in both directions.

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D'Amours, Julie, Stéphanie Thibodeau und Réjean Fortin. „Comparison of lake sturgeon (Acipenser fulvescens), Stizostedion spp., Catostomus spp., Moxostoma spp., quillback (Carpiodes cyprinus), and mooneye (Hiodon tergisus) larval drift in Des Prairies River, Quebec“. Canadian Journal of Zoology 79, Nr. 8 (01.08.2001): 1472–89. http://dx.doi.org/10.1139/z01-095.

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Several fish species that spawn in lotic habitats have a larval-drift phase which is a major determinant of their reproductive success. The main objective of this study was to compare seasonal, diel, longitudinal, transverse, and vertical variations in rates of lake sturgeon (Acipenser fulvescens), Stizostedion spp., Catostomus spp., Moxostoma spp., quillback (Carpiodes cyprinus), and mooneye (Hiodon tergisus) larval drift in Des Prairies River (DPR) near Montreal (Quebec), which is one of the major lotic spawning habitats of the St. Lawrence River system. Larval sampling was conducted in the spring of 1994 and 1995 for the six taxa, and on a more restricted basis for lake sturgeon in 19961998, using drift nets set at several transects, stations, depths, and periods of the day, along a 19 km long section of river beginning ca. 2 km downstream from the DPR power house. For all taxa except lake sturgeon, peak larval drift occurred ca. 1 week earlier in 1995 than in 1994. The sequence was very similar between years, beginning with Stizostedion spp., followed by Catostomus spp., then lake sturgeon, quillback, and mooneye drifting simultaneously, and finally Moxostoma spp. Generally, for all taxa except quillback, whose multimodal drift pattern suggests intermittent, prolonged spawning, larval-drift profiles showed one major seasonal mode, which was observed simultaneously at all transects. For all taxa except quillback, drift rates peaked between 21:00 and 03:00 and were minimal during daylight hours. Lake sturgeon and Stizostedion spp. larval drift rates decreased radically from the most upstream to the most downstream transect, suggesting that both taxa spawn mostly in the vicinity of the DPR power house. More studies are required to explain this longitudinal decline in drift rates, particularly for lake sturgeon. The other taxa showed longitudinal variation in larval drift rates, suggesting that they spawn near the DPR power house and (or) in the Île de Pierre Rapids, ca. 12 km downstream. At all transects, larval drift rates for the six taxa were generally higher in the right half (Montreal) of the river, suggesting that eggs are deposited mostly in this part of the river at the two major spawning areas and that larvae tend to remain in the same general corridors during downstream migration. For all taxa, though to a lesser extent for lake sturgeon, nocturnal drift rates tend to be higher near the surface than at mid-depth and near the bottom, the reverse situation being observed for diurnal drift rates.

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Hensleigh, Jay E., und Andrew P. Hendry. „Rheotactic response of fry from beach-spawning populations of sockeye salmon: evolution after selection is relaxed“. Canadian Journal of Zoology 76, Nr. 12 (01.12.1998): 2186–93. http://dx.doi.org/10.1139/z98-174.

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Rheotactic response was quantified for newly emerged sockeye salmon (Oncorhynchus nerka) fry from a beach population (Pleasure Point) and from an adjacent inlet population (Cedar River). The Pleasure Point population was small in number and had been established by straying from the much larger Cedar River population no more than 13 generations previously. When tested in laboratory raceways, fry from the Cedar River population were displaced downstream in the dark but not in the light. Such behavior is typical of inlet populations and presumably reflects selection for rapid movement to rearing lakes with minimal losses to predation. Fry from the Pleasure Point population showed greater downstream displacement than the Cedar River fry. Behavioral divergence of the Pleasure Point population could not be explained by selection, because water movement was absent from the beach environment. Genetic drift appeared to be a more plausible divergence mechanism. We suggest that the rheotactic response of beach populations should reflect the founding genotypes, gene flow from other populations, and random genetic drift. The results of previously published studies on the rheotactic response of beach fry in two other lake systems qualitatively support our hypothesis.

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Burman, Anton J., Richard D. Hedger, J. Gunnar I. Hellström, Anders G. Andersson und Line E. Sundt-Hansen. „Modelling the downstream longitudinal effects of frequent hydropeaking on the spawning potential and stranding susceptibility of salmonids“. Science of The Total Environment 796 (November 2021): 148999. http://dx.doi.org/10.1016/j.scitotenv.2021.148999.

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Couto, Thiago Belisario d’Araújo, Jansen Zuanon, Julian D. Olden und Gonçalo Ferraz. „Longitudinal variability in lateral hydrologic connectivity shapes fish occurrence in temporary floodplain ponds“. Canadian Journal of Fisheries and Aquatic Sciences 75, Nr. 2 (Februar 2018): 319–28. http://dx.doi.org/10.1139/cjfas-2016-0388.

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Dynamic flow regimes maintain critical connections between main channel and adjacent floodplain habitats that provide fish access to shelter, foraging, and spawning opportunities. Our study advances the understanding of these processes by exploring the importance of coupled longitudinal–lateral connectivity for determining species occurrence in headwater streams of the Amazon. Using a multispecies occupancy model, we revealed a clear pattern of species addition in the downstream direction in temporary floodplain ponds, associated with changes in the pool of potential colonists present in the channel and with increasing lateral hydrologic connectivity. Species that are more tolerant of stagnant waters and those able to disperse in shallow habitats (e.g., Anablepsoides micropus) occurred frequently in ponds along the entire longitudinal extent, whereas those species preferring lotic habitats were present only in the most downstream sites. We also observed increasing similarity of pond and channel communities with distance downstream. This study provides insights on the spatial structuring of tropical fish communities in response to flood-induced hydrologic connectivity and further highlights the vulnerability of floodplain fishes to modification in flooding regimes.

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Murphy, Michael L., K. V. Koski, J. Mitchel Lorenz und John F. Thedinga. „Downstream migrations of juvenile Pacific salmon (Oncorhynchus spp.) in a glacial transboundary river“. Canadian Journal of Fisheries and Aquatic Sciences 54, Nr. 12 (01.12.1997): 2837–46. http://dx.doi.org/10.1139/f97-178.

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Migrations of juvenile Pacific salmon (Oncorhynchus spp.) in the glacial Taku River (seventh order) were studied to assess movement from upriver spawning areas (in British Columbia) into lower-river rearing areas (in Alaska). Differences between fyke-net catches in the river and seine catches in the river's estuary indicated that many downstream migrants remained in the lower river instead of migrating to sea. In particular, age-0 coho salmon (O. kisutch) and chinook salmon (O. tshawytscha) moved downriver from May to November but were not caught in the estuary. Age-0 sockeye salmon (O. nerka), coho presmolts, and other groups delayed entry into the estuary after moving downriver. We tagged groups of juvenile coho (ages 0-2) from the fyke net with coded-wire to determine when they left the river. One-third of all tags recovered from sport and commercial fisheries occurred 2-3 years later, showing that many coho remained in fresh water for 1-2 years after moving to the lower river. Lower-river areas of large glacial rivers like the Taku River can provide essential rearing habitat for juvenile salmon spawned upriver and are important to consider in integrated whole-river management of transboundary rivers.

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Tanimoto, M., J. B. Robins, M. F. O'Neill, I. A. Halliday und A. B. Campbell. „Quantifying the effects of climate change and water abstraction on a population of barramundi (Lates calcarifer), a diadromous estuarine finfish“. Marine and Freshwater Research 63, Nr. 8 (2012): 715. http://dx.doi.org/10.1071/mf11246.

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Many aquatic species are linked to environmental drivers such as temperature and salinity through processes such as spawning, recruitment and growth. Information is needed on how fished species may respond to altered environmental drivers under climate change so that adaptive management strategies can be developed. Barramundi (Lates calcarifer) is a highly prized species of the Indo-West Pacific, whose recruitment and growth is driven by river discharge. We developed a monthly age- and length-structured population model for barramundi. Monte Carlo Markov Chain simulations were used to explore the population’s response to altered river discharges under modelled total licenced water abstraction and projected climate change, derived and downscaled from Global Climate Model A1FI. Mean values of exploitable biomass, annual catch, maximum sustainable yield and spawning stock size were significantly reduced under scenarios where river discharge was reduced; despite including uncertainty. These results suggest that the upstream use of water resources and climate change have potential to significantly reduce downstream barramundi stock sizes and harvests and may undermine the inherent resilience of estuarine-dependent fisheries.

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Danancher, Delphine, Jacques Labonne, Roger Pradel und Philippe Gaudin. „Capturerecapture estimates of space used in streams (CRESUS) at the population scale: case study on Zingel asper (percid), a threatened species of the Rhône catchment“. Canadian Journal of Fisheries and Aquatic Sciences 61, Nr. 3 (01.03.2004): 476–86. http://dx.doi.org/10.1139/f04-004.

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In this study, capturemarkrecapture statistics were applied to spatial recapture histories to assess the intensity of fish restricted movements along the longitudinal axis of a river using a previously described model for survival and recruitment analysis. Adapting the stopover estimation method to spatial data, movement probabilities were then used to estimate space used at the population scale. This capturerecapture estimates of space used in streams (CRESUS) method may thus be seen as a complementary tool of classic home range methods and should be used to explore the consequence of behavioural strategies on population mechanisms. We propose a methodological example where movements and space use strategies of a Zingel asper (percid) population in the Beaume River (Ardèche, France) were directly estimated at the population scale taking account of the effects of different biotic or abiotic factors. Results showed differences in Z. asper space use patterns among sexes, periods of biological cycle (growing and spawning period), and types of mesohabitat. Downstream movements were more important during the spawning period and by the way the riffle was more intensively used.

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Heim, Kurt C., Thomas E. McMahon, Steven T. Kalinowski, Brian D. Ertel und Todd M. Koel. „Abiotic conditions are unlikely to mediate hybridization between invasive rainbow trout and native Yellowstone cutthroat trout in a high-elevation metapopulation“. Canadian Journal of Fisheries and Aquatic Sciences 77, Nr. 9 (September 2020): 1433–45. http://dx.doi.org/10.1139/cjfas-2019-0317.

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Understanding factors mediating hybridization between native and invasive species is crucial for conservation. We assessed the spatial distribution of hybridization between invasive rainbow trout (Oncorhynchus mykiss) and native Yellowstone cutthroat trout (Oncorhynchus clarkii bouveri) in the Lamar River of Yellowstone National Park using a paired telemetry and genetic dataset. Spawning populations containing hybrids (15/30) occupied the full spectrum of abiotic conditions in the watershed (stream temperature, stream size, runoff timing), including an intermittent stream that dried completely in late June, and mainstem spawning locations. Hybrids and rainbow trout occupied an entire high-elevation (∼2500–1900 m) tributary where rainbow trout ancestry was highest in headwaters and decreased downstream. Fluvial distance to this ostensible source population was the only covariate included in top hybridization models; effects of abiotic covariates and stocking intensity were relatively weak. In this watershed, abiotic conditions are unlikely to mediate continued hybridization. We conclude that management intervention is important for the persistence of nonhybridized Yellowstone cutthroat trout and highlight the value of pairing telemetry with genetic analysis to identify and characterize populations for hybridization assessments.

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Fu, Xiao-li, Da-mei Li und Guo-yu Jin. „Calculation of Flow Field and Analysis of Spawning Sites for Chinese Sturgeon in the Downstream of Gezhouba Dam“. Journal of Hydrodynamics 19, Nr. 1 (Februar 2007): 78–83. http://dx.doi.org/10.1016/s1001-6058(07)60031-6.

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Arai, Takaomi, und Nobuyuki Miyazaki. „Use of otolith microchemistry to estimate the migratory history of the Russian sturgeon, Acipenser guldenstadti“. Journal of the Marine Biological Association of the United Kingdom 81, Nr. 4 (August 2001): 709–10. http://dx.doi.org/10.1017/s0025315401004465.

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Ontogenic change patterns in otolith Sr:Ca ratios were examined in the Russian sturgeon, Acipenser guldenstadti in the Caspian Sea. Otolith Sr:Ca ratios fluctuated widely during the life history in accordance with the migration pattern from freshwater to brackish water habitats, i.e. all specimens exhibited a typical anadromous pattern in the ratio. Several specimens had two transition points in otolith Sr:Ca ratios from the low ratios to the high indicating that those specimens had a flexible migration strategy in the ambient water and had the possibility of migrating downstream to the Caspian Sea multiple times after spawning in a freshwater habitat.

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Bell, Donovan A., Ryan P. Kovach, Scott C. Vulstek, John E. Joyce und David A. Tallmon. „Climate-induced trends in predator–prey synchrony differ across life-history stages of an anadromous salmonid“. Canadian Journal of Fisheries and Aquatic Sciences 74, Nr. 9 (September 2017): 1431–38. http://dx.doi.org/10.1139/cjfas-2016-0309.

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Differential climate-induced shifts in phenology can create mismatches between predators and prey, but few studies have examined predator–prey mismatch across multiple life-history stages. We used long-term data from a warming stream with shifting salmonid migration timings to quantify intra-annual migration synchrony between predatory Dolly Varden (Salvelinus malma) and Pacific salmon prey and examined how predator–prey synchrony has been influenced by climate change. We demonstrate that Dolly Varden have become increasingly mismatched with spring downstream migrations of abundant pink salmon (Oncorhynchus gorbuscha) juveniles. However, Dolly Varden have remained matched with fall upstream migrations of spawning Pacific salmon, including coho (Oncorhynchus kisutch), sockeye (Oncorhynchus nerka), and pink salmon. Downstream predator–prey migration synchrony decreased over time and with higher temperatures, particularly with pink salmon. In contrast, upstream migration synchrony was temporally stable and increased with rising temperatures. Differing trends in Dolly Varden predator–prey synchrony may be explained by the direct use of salmon to cue upstream migration, but not downstream migration. Overall, we show that climate change can have differing impacts on predator–prey synchrony across life-history stages.

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