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Auswahl der wissenschaftlichen Literatur zum Thema „Downstream spawning“
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Zeitschriftenartikel zum Thema "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.
Dissertationen zum Thema "Downstream spawning"
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Adolfsson, Oscar. „Consequences on population dynamics following regained connectivity in pike (Esox lucius) spawning location“. Thesis, Linnéuniversitetet, Institutionen för biologi och miljö (BOM), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-104213.
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Distributional movements of subpopulations may act as a buffer to prevent the loss of a species in a certain area. However, within subpopulations adaptations may evolve that makes the inhabitants of a certain habitat to better cope with prevailing environmental conditions. If such traits are related to reproduction, they may reduce the opportunity of gene exchange between other subpopulations. Also, a lack of adaptations to a specific habitat may be what prevents a group of individuals, arriving from an adjacent habitat, to successfully colonize an area where a previous subpopulation has been lost.This is the report from a field study conducted in the wetland Lake Långsjön, that in 2018 was restored in order to promote the recruitment of anadromous pike (Esox lucius) to the Baltic Sea. Commonly, wetlands that are restored to promote anadromous pike recruitment, are constructed so that they enable spawning migration from the sea towards the wetland and juvenile emigration towards the sea only. In that sense Lake Långsjön is different, from other wetlands restored for the same purpose, due to that it is connected to both the Baltic Sea and an upstream located freshwater lake. By quantifying the migration of pike (spawners and juveniles) in both directions I explore the consequences that the regained connectivity between the Lake Långsjön and the coast may have on the population dynamics within this wetland; (i) whether it is potentially influenced by allowing mixture between pike with different migratory strategies for spawning (anadromous and potamodromous), (ii) what drivers there are of pike fry emigration and how they may influence the pike fry emigration route and (iii) whether or not the pike of potamodromous origin, resident in the upstream located lake, may work as a source, providing the Baltic Sea with pike juveniles. Pike spawners arriving in the wetland were caught in traps between March - April. Pike fry were caught withing the wetland with fyke nets and by netting. Emigrating pike fry were caught in fyke nets. Findings suggest that spawning migration patterns do not differ between anadromous and potamodromous pike. However, the spawners arriving from the Baltic Sea I suggested are to be composed by offspring of potamodromous origin, possibly hatched during the previous season, and that they as juveniles swam downstream. This, in turn, indicates that the potamodromous stock can help establish an anadromous stock in the Baltic Sea. Still, due to the observation of pike fry displaying an emigration behaviour upstream, origin is identified as a factor that may influence the pike fry emigration route. Also, this emigration pattern seems to indicate a heritable trait that has not been described before among pike, that of downstream spawning. The restoration of the wetland and the regained connectivity is key, both for the ability to restock the Baltic Sea with pike juveniles but also to ensure the conservation of a fascinating stock of pike exhibiting a unique spawning strategy
Buchteile zum Thema "Downstream spawning"
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„Anadromous Sturgeons: Habitats, Threats, and Management“. In Anadromous Sturgeons: Habitats, Threats, and Management, herausgegeben von Henrietta I. Jager, Mark S. Bevelhimer, Ken B. Lepla, James A. Chandler und Webb Van Winkle. American Fisheries Society, 2007. http://dx.doi.org/10.47886/9781888569919.ch18.
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<em>Abstract.</em>— This paper describes a simulation study of reconnection options for white sturgeon <em>Acipenser transmontanus</em> subpopulations in adjacent river segments above and below CJ Strike Dam on the Snake River, Idaho, USA. In contrast to the downstream river segment, the upstream river segment is long and has areas that are suitable for spawning during normal and wet hydrologic conditions. We evaluated demographic and genetic consequences of upstream and downstream passage using different model assumptions about trashrack spacing and density-dependent effects on the spawning interval. Our genetic results predict that, although reconnection would introduce new alleles to the upstream subpopulation, it would also preserve alleles from the downstream subpopulation by propagating them in the larger subpopulation above the dam. Our demographic results predict that halving the space between trashracks would have large and unequivocal benefits, whereas the predicted effects of reconnection were smaller and more sensitive to model assumptions. Simulated upstream passage tended to benefit both subpopulations only in the absence of density-dependent limitation. In the presence of density dependence, the combination of halved trashrack spacing and upstream and downstream passage produced the best results. Narrower trashracks kept spawning adults in the upstream segment with spawning habitat, while allowing their progeny to migrate downstream. Screening appears to be the best option for such a species in this configuration of a long river segment acting as a demographic source above a short one acting as a demographic sink.
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„Fishery Resources, Environment, and Conservation in the Mississippi and Yangtze (Changjiang) River Basins“. In Fishery Resources, Environment, and Conservation in the Mississippi and Yangtze (Changjiang) River Basins, herausgegeben von Jing Yuan, Yuguo Xia, Zhongjie Li, Zhan Yin und Jiashou Liu. American Fisheries Society, 2016. http://dx.doi.org/10.47886/9781934874448.ch10.
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<em>Abstract</em>.—The Hanjiang River is the largest tributary of the Yangtze River and contains Danjiangkou Dam, which forms Danjiangkou Reservoir in the middle and upper reaches of the river. During the past 50 years, fisheries resources have changed significantly in the middle and lower Hanjiang River and in Danjiangkou Reservoir. Spawning grounds for major carps and other commercially important fishes have disappeared. Downstream of Danjiangkou Dam, total egg quantity spawned by major carps and other commercially im portant fishes have decreased while similar measures from small-bodied fishes have increased. Important commercial fishes have experienced delayed spawning times and decreased growth. Overall catches of commercial fishes have decreased downstream of the dam, though increased upstream. Some exotic fishes captured in the Danjiangkou Reservoir were likely escapees from cage-culture fish farms in the reservoir or from land-based fish farms around the reservoir. Changes in fisheries resources were presumed related to reservoir management strategies, which produced a narrower range of year-round water temperatures and caused decreases in seasonal water flow variation downstream, overfishing, and eutrophication in the reservoir. To implement a national water diversion policy in central China, the height of the Danjiangkou Dam was increased 15 m in 2012, which significantly increased the impoundment area of the Danjiangkou Reservoir at the end of 2014. Further changes in fisheries resources can be expected in the future. At the present time, management and conservation strategies for fisheries resources need to be developed to ensure future fisheries sustainability for both the Hanjiang River and the Danjiangkou Reservoir.
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„Nutrients in Salmonid Ecosystems: Sustaining Production and Biodiversity“. In Nutrients in Salmonid Ecosystems: Sustaining Production and Biodiversity, herausgegeben von Thomas C. O’Keefe und Rick T. Edwards. American Fisheries Society, 2003. http://dx.doi.org/10.47886/9781888569445.ch8.
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<em>Abstract.</em>—Evidence for the importance of marine-derived nutrient (MDN) inputs from spawning salmon to terrestrial and freshwater ecosystems is rapidly accumulating, but the mechanisms by which MDN inputs are transferred and stored within spawning streams and their catchments are poorly understood. Presumed marine isotope signals have been found in riparian vegetation, suggesting that marine nutrients may impact terrestrial plant communities. Studies have suggested that MDN increases stream productivity both immediately after spawning and during the following spring. The peak of many spawning runs occurs at the end of the summer growing season, suggesting that overwinter storage of MDN must be occurring. A potential location for lateral nutrient transfers and overwinter MDN storage is the hyporheic zone within stream channels or in adjacent riparian floodplains. Within Lynx Creek, a sockeyespawning stream in the Wood River Lake drainage in southwestern Alaska, extensive floodplain hyporheic zones occur along spawning reaches. Surface water moves into the floodplain hyporheic zone and flows downstream 70–80 m before returning to the stream. Ambient nutrient concentrations within the surface and hyporheic zone indicate that marine-derived nitrogen and phosphorus entered hyporheic flow paths, where they were rapidly removed from the water during the spawning run. Some marine-derived ammonium was remobilized as nitrate and continued to move, but marine-derived phosphorus was stored for at least the duration of the spawning run. Hyporheic sediments are not scoured by winter floods and contain active heterotrophic biological communities that are capable of storing and transforming various forms of MDN. Thus, it seems likely that hyporheic storage and re-release of marinederived nutrients is an important mechanism by which salmon-derived nutrients are retained over winter within stream ecosystems and subsequently made available to primary producers the following growing season.
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„Paddlefish Management, Propagation, and Conservation in the 21st Century“. In Paddlefish Management, Propagation, and Conservation in the 21st Century, herausgegeben von MAURICE F. METTEE, PATRICK E. O’NEIL und STEVEN J. RIDER. American Fisheries Society, 2009. http://dx.doi.org/10.47886/9781934874127.ch5.
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<em>Abstract</em>.—This paper describes the movements of 102 sonic tagged paddlefish released in the Alabama River from 2001 to 2005 and 10 sonic fish released in Mobile Bay in 2006, evaluates possible spawning site fidelity at Millers Ferry Lock and Dam, and presents fisheries, river discharge, and lock use data in support of our recommendation to implement January through April fish passage operations at two locks and dams in the Alabama River. Fifty-seven paddlefish released in the Alabama River remained between Millers Ferry and Claiborne locks and dams. Thirty-four fish moved downstream past Claiborne Lock and Dam and inhabited widely separated sites in the Alabama, Tensaw, and Tombigbee rivers. One fish moved upstream through Millers Ferry lock chamber and was detected in Dannelly Reservoir for 2 years. Spawning site fidelity is suggested based on the return of 15 tagged fish to Millers Ferry tailwater area 1 or 2 years following their release. Four of eight paddlefish released in Mobile Bay remained in the Tensaw River system throughout the study. Four other fish were detected above and below Claiborne Lock and Dam in the Alabama River. Movement patterns documented during our study established an important life history link between spawning habitats in the Alabama River, summer feeding habitats in the Mobile–Tensaw River delta, and winter feeding habitats in Mobile Bay. Proposed fish passage operations at Claiborne and Millers Ferry locks and dams should not be expensive to implement and they should not adversely affect navigation, hydroelectric generation schedules, and industrial water needs along the river.
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„Challenges for Diadromous Fishes in a Dynamic Global Environment“. In Challenges for Diadromous Fishes in a Dynamic Global Environment, herausgegeben von Timothy D. Jardine, Jean-Marc Roussel, Sean C. Mitchell und Richard A. Cunjak. American Fisheries Society, 2009. http://dx.doi.org/10.47886/9781934874080.ch27.
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<em>Abstract</em>.—We used stable isotope analysis in an attempt to detect marine subsidies from anadromous fish to freshwater benthos in four river systems draining to the Atlantic Ocean. Benthic invertebrates in the West River, Nova Scotia, Canada, had elevated d<sup>13</sup>C, d<sup>15</sup>N, and d<sup>34</sup>S values in a downstream reach that suggested consumption of marine-derived organic matter from spawning blueback herring <em>Alosa aestivalis</em>. In Doctor’s Brook, Nova Scotia, the arrival of rainbow smelt <em>Osmerus mordax </em>to spawn led to rapid increases in the d<sup>13</sup>C and d<sup>15</sup>N of a predatory stonefly (Perlidae), but lower trophic levels (mayflies and biofilm) showed inconsistent responses. Sculpin <em>Cottus </em>sp. showed no evidence of predation on Atlantic salmon <em>Salmo salar </em>eggs in Catamaran Brook, New Brunswick, Canada or the Scorff River, Brittany, France. These analyses suggest that marine organic matter subsidies, in the form of direct consumption of eggs and/or carcasses, are important in streams with concentrated spawning activity such as by alosid and osmerid species, whereas carbon and nitrogen contributions from more sparse spawning species such as by Atlantic salmon may be minimal.
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„Early Life History of Fishes in the San Francisco Estuary and Watershed“. In Early Life History of Fishes in the San Francisco Estuary and Watershed, herausgegeben von Andrew K. Rockriver. American Fisheries Society, 2004. http://dx.doi.org/10.47886/9781888569599.ch7.
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<em>Abstract.</em>—The goal of this study was to determine if the vertical distribution of larval delta smelt <em>Hypomesus transpacificus </em>and striped bass <em>Morone saxatilis </em>was affected by tidal stage and diel period. Delta smelt and striped bass have similar early life histories in that their larvae drift downstream from freshwater spawning habitats to brackish water rearing habitats. Little is known on whether the larvae undergo a vertical migration as they move downstream. Conical plankton nets were used to collect larval fishes from the surface, middle, and bottom sections of the main channels of the Sacramento and San Joaquin rivers. Samples were collected over six paired day–night cruises. Approximately 45,000 fish were collected; 82% were striped bass and 2% were delta smelt. More delta smelt were caught at night than during the day, and more at middle depth than surface or bottom. Very few striped bass were found at surface during day; most were caught at middle depth. Both species were fairly dispersed throughout the water column at night. Although striped bass larvae appear to undergo a small surface to middepth migration, this study indicates that larval delta smelt and striped bass do not undergo a mass diel or tidal vertical migration as they drift down the Sacramento and San Joaquin rivers.
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„Black Bass Diversity: Multidisciplinary Science for Conservation“. In Black Bass Diversity: Multidisciplinary Science for Conservation, herausgegeben von Steven M. Sammons und Laurie A. Earley. American Fisheries Society, 2015. http://dx.doi.org/10.47886/9781934874400.ch22.
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<em>Abstract</em>.—Movement and habitat use of Shoal Bass <em>Micropterus cataractae</em> were evaluated in the flow-regulated Chattahoochee River, Alabama–Georgia. Forty Shoal Bass were tracked using radio tags in a 2-km section of river between two impoundments. Movement of Shoal Bass in this population was low, and most fish never left the reach of river where shoal habitat existed. A few fish migrated approximately 10 km up a tributary stream during the spring to reach a large shoal complex, presumably to spawn. No fish were found in the downstream impoundment or associated tributary streams. Shoal Bass were most commonly found in areas with bedrock substrate and cover, especially in the spring. Use of a tributary for presumed spawning indicates that this population of Shoal Bass was less isolated than many others in the Chattahoochee River.
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„Island in the Stream: Oceanography and Fisheries of the Charleston Bump“. In Island in the Stream: Oceanography and Fisheries of the Charleston Bump, herausgegeben von John J. Govoni und Jonathan A. Hare. American Fisheries Society, 2001. http://dx.doi.org/10.47886/9781888569230.ch7.
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<em> Abstract.</em>—The region of the outer continental shelf and upper slope, encompassed roughly by 32 and 33°N and 78 and 79°W, is unique within the southeastern Atlantic coast of the United States because of the frequent presence of large (amplitudes of 50-100 km), cyclonic eddies. These eddies develop continuously north of the deflection of the Gulf Stream at the Charleston Bump and decay downstream. The cyclonic circulation of these eddies brings nutrient-rich water from deep and off the shelf edge to near surface and results in enhanced primary production. Succession of Zooplankton assemblages, driven by enhanced primary production, might serve fish production by providing an exceptional, and more continuous food supply for larval fishes spawned in or entrained into eddies. In addition, larval fishes that risk entrainment into the Gulf Stream and consequent loss from local populations, can be retained on, or near, the shelf when embedded within these eddies. The residence of an eddy within the region ranges from a week to a month or two, while the larval period of most fishes ranges from weeks to months. The large-scale eddies in the region develop most frequently in winter when the Gulf Stream is in its strongly deflected mode, coincident with the spawning of a suite of commercially important fishes. Although the region of the Charleston Gyre has the potential to act as an important spawning and nursery habitat, published evidence of usage of the habitat afforded by large scale eddies in this region is weak. High concentrations of larval fishes occasionally occur in the region, but there is no indication of high concentrations of fish eggs. With its high primary and secondary production, succession of Zooplankton assemblages, and retention mechanism, the region of the Gyre may constitute an important spawning and nursery habitat for fishes, but more research aimed at assessing this potential is necessary.
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„Muskellunge Management: Fifty Years of Cooperation Among Anglers, Scientists, and Fisheries Biologists“. In Muskellunge Management: Fifty Years of Cooperation Among Anglers, Scientists, and Fisheries Biologists, herausgegeben von Steven J. Kerr und Brandon Jones. American Fisheries Society, 2017. http://dx.doi.org/10.47886/9781934874462.ch4.
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<em>Abstract</em>.—We report on results of a Muskellunge <em>Esox masquinongy </em>tagging project, which was conducted on the Saint John River, New Brunswick, from 2006 to 2015 (inclusive). During that period of time, 691 Muskellunge were angled, tagged, and released by members of the Saint John River Chapter of Muskies Canada Inc. By the end of the 2015 angling season, a total of 64 (9.3%) tagged Muskellunge had been recaptured by angling. An additional four tagged fish were captured at the Mactaquac Dam fishway. Most Muskellunge were observed to establish discrete summer home ranges from which there was little, if any, movement. Transitional movements were believed to occur during the spring and fall, associated with spawning as well as the establishment of summer and winter ranges. Muskellunge movements that were documented in this study occurred in both upstream and downstream directions in equal proportion. Muskellunge also demonstrated the ability to move long distances both upstream and downstream, including passage over/through the Mactaquac Dam. Observations of Muskellunge behavior and movements from this study are generally consistent with observations (small home ranges, males more sedentary than females, movements seasonal in nature, capable of long distance movements, etc.) reported from similar tagging studies in other North American jurisdictions. Future efforts will be directed to obtaining additional information on recaptured fish. With additional recapture information, a more detailed analysis of Muskellunge in the Saint John watershed can be completed.
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„Early Life History of Fishes in the San Francisco Estuary and Watershed“. In Early Life History of Fishes in the San Francisco Estuary and Watershed, herausgegeben von Michael Dege und Larry R. Brown. American Fisheries Society, 2004. http://dx.doi.org/10.47886/9781888569599.ch4.
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<em>Abstract.</em>—We analyzed data on spring and summertime larval and juvenile fish distribution and abundance in the upper San Francisco Estuary (SFE), California between 1995 and 2001. The upper SFE includes the tidal freshwater areas of the Sacramento–San Joaquin Delta downstream to the euryhaline environment of San Pablo Bay. The sampling period included years with a variety of outflow conditions. Fifty taxa were collected using a larval tow net. Two common native species, delta smelt <em>Hypomesus transpacificus </em>and longfin smelt <em>Spirinchus thaleichthys</em>, and four common alien taxa, striped bass <em>Morone saxatilis</em>, threadfin shad <em>Dorosoma petenense</em>, gobies of the genus <em>Tridentiger</em>, and yellowfin goby <em>Acanthogobius flavimanus</em>, were selected for detailed analysis. Outflow conditions had a strong influence on the geographic distribution of most of the species, but distribution with respect to the 2 psu isohaline (X2) was not affected. The distribution patterns of delta smelt, longfin smelt, and striped bass were consistent with larvae moving from upstream freshwater spawning areas to downstream estuarine rearing areas. There were no obvious relationships of outflow with annual abundance indices. Our results support the idea of using X2 as an organizing principle in understanding the ecology of larval fishes in the upper SFE. Additional years of sampling will likely lead to additional insights into the early life history of upper SFE fishes.