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1
Lindmark, Elianne M. "Flow design for migrating fish /." Luleå : Division of Fluid Mechanics, Department of Applied Physics and Mechanical Engineering, Luleå University of Technology, 2008. http://epubl.luth.se/1402-1544/2008/55.
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Lindmark, Elianne. "Flow design for migrating fish." Doctoral thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-25698.
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The utilization of rivers for hydropower production leads to problems for migrating fish, such as Atlantic salmon (Salmo salar) and sea trout (Salmo trutta). Both salmon and trout reproduce in fresh water, but spend their adult years at sea. To overcome man-made obstructions to and from the spawning grounds the fish needs help. Fishways for upstream migrating fish is an old technique; however the efficiency is often low due to inefficient attraction water. The upstream migrating fish are attracted to high water velocities and often approach the dominating flow from the turbine outlet instead of entering the fishway. For the downstream migrating smolt (young fish) the only way to pass a power plant is often via the turbines, with a high mortality as a result. The smolt follow the main flow in the river on the way downstream avoiding high accelerations or retardations. This thesis covers investigations on both an attraction channel to increase the water velocity at the inlet of a fishway for upstream migraters and a smolt guidance device to guide the smolt away from the turbine inlet to a safer passage route. To investigate the properties of the attraction channel both model and field experiments have been carried out, as well as numerical studies. The velocity in the channel has been examined with Laser-Doppler-Velocimetry and the flow field in the channel was studied using Particle-Imaging- Velovimetry. The results show that the water can be accelerated 38 % compared with the surrounding velocity. How far the increase in velocity is present depends on the depth of the attraction channel. The field tests carried out at Sikfors hydropower plant in Piteå River (Sweden) show that the fish do swim through the channel, providing that the channel is black. The flow around a smolt guidance device has been studied using numerical simulations. The aim of the device is to redirect the surface flow from the turbines to the spillway. By doing this, the shallow swimming smolt will also be guided towards the spillway and a much safer route. The results show that the guidance device successfully redirects the surface flow without creating any strong acceleration that may scare the fish.Godkänd; 2008; 20081113 (ysko)
3
Baumgartner, Lee Jason, and n/a. "Effects of weirs on fish movements in the Murray-Darling Basin." University of Canberra. Resource, Environmental & Heritage Sciences, 2005. http://erl.canberra.edu.au./public/adt-AUC20051129.142046.
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Dams and weirs are widely implicated in large-scale declines in both the range and abundance of aquatic fauna. Although many factors are involved, such declines are commonly attributed to the prevention or reduction of migration, reductions in available habitat, alteration of natural flow regimes and changes to physicochemical characteristics. In Australia, studies into the ecological effects of these impacts are limited, and have concentrated mainly on species of recreational and commercial importance. Subsequently, the adverse effects of dams and weirs, and suitable methods of mitigation, remain largely unknown for many other taxa. Therefore, the major aim of this thesis is to investigate the ecological effects of dam and weir construction on previously unstudied migratory assemblages of fish and macroinvertebrates in the Murray-Darling Basin. It is anticipated that the results of these studies will feed back into improved management strategies that help arrest the previously observed declines of aquatic fauna. Initially, fish communities were sampled, by boat electrofishing, from both reference sites and downstream of Balranald and Redbank weirs on the lower reaches of the Murrumbidgee River, Australia. Sampling was stratified over large spatial and temporal scales to gain a comprehensive understanding of species most affected by the presence of these two barriers. In general, the weirs obstructed fish migrations during summer and autumn and many species of small-bodied fish such as Australian smelt, western carp gudgeon, fly-specked hardyhead and crimson-spotted rainbowfish accumulated downstream of Balranald Weir. In addition, downstream accumulations of juveniles of larger-bodied species such as bony herring, common carp and goldfish were also detected. Although many previous studies had either documented or hypothesised that upstream migrating fish accumulate downstream of migration barriers, none attempted to quantify the size of such populations. Therefore, a simple but efficient method to estimate the size of migratory populations was assessed at the Balranald Weir site. The application of two commonly used estimation techniques yielded relatively reliable results for seven species that accumulated downstream of the weir. Population size estimates were greatest for most species during summer and autumn, where accumulations as high as 800 fish per day were detected. The largest calculated population size estimates, in addition to the
greatest temporal variation, of any individual species was observed in bony herring. Given the simplicity of the technique and the relative accuracy of population estimates, it was concluded that these methods could easily be applied to other weirs where the size of migratory populations is of particular interest. A study investigating the effects of Yanco Weir on the diets of three migratory percichthyid species, Murray cod, trout cod and golden perch was also conducted. Observed spatial variation in a number of trophic processes strongly implicated Yanco Weir as a major contributor to increased competition among percichthyid species on the Murrumbidgee River. The greater relative abundance of percichthyids from downstream samples, combined with increases in dietary overlap and a greater percentage of empty stomachs, also suggested percichthyids may be significantly affecting the relative abundance of potential prey items such as freshwater prawns and Australian smelt. These significant changes in dietary composition were likely related to migratory behaviour, as these species accumulated downstream of the weir, and could be readily expected at other sites where passage is obstructed. It was suggested that the construction of suitable fish passage facilities would effectively reduce the probability of migratory fish accumulating and, subsequently, potential effects of dams and weirs on trophic processes. Since it was established that dams and weirs of the Murrumbidgee River were significantly affecting migratory fish communities, an innovative but relatively inexpensive fishway design, the Deelder fish lock (after Deelder, 1958), was constructed and assessed for wider application throughout the Murray-Darling Basin. The Deelder lock was effective at mitigating the effects of Balranald Weir by providing passage for a wide range of size classes and species of fish; but importantly, the structure enabled the passage of most species previously observed to accumulate downstream of the structure. Most significant was the ability of the fish lock to pass substantial numbers of small-bodied fish, which were previously not considered migratory, suggesting that these species should be considered when developing options to mitigate the effects of other dams and weirs throughout the Murray-Darling Basin. A significant finding of this study was the realisation that substantially more species and size classes of Australian native fish are migratory than previously thought.
Subsequently, it is recommended that, when designing facilities to mitigate the effects of a dam or weir, the structure of the entire migratory community is considered when developing operating parameters. Various options for mitigating the effects of dams and weirs are discussed, but it was concluded that the construction of effective fishways would be the most appropriate means of restoring migration pathways to Australian native fish. A strategic approach for assessing and adaptively mitigating the effects of dams and weirs is presented and discussed.
4
Bin, Asad S. M. Sayeed. "Laser-based Measurements connected to Fish Migration." Licentiate thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-59663.
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Hydropower is one of the main sources for Sweden’s energy, which is clean and renewable. It is a clean energy source because no fuels are burned which does not pollute the air and it is a renewable energy source as it only uses natural water cycle for generating energy. However, hydropower has some consequences in nature, such as creating dams in rivers and changing water flow directions, which lead to some problems for migrating fishes. These fish migration problems are mostly studied from a biological point of view but more detailed studies are required from a fundamental fluid mechanics point of view. Fish migrates when ecological imbalance is created and one of the reasons for this imbalance is having dams for hydropower. Some dams have fishways or fish ladders to allow fish to migrate past the dam and during swimming or passing this fishway or fish ladder, fish has to tackle some sort of flow obstructions like, turbine intakes, stones and concrete structures etc. Fluid flow characteristics in fish ladders or fishways during fish migration is crucial for designing effective fishways to migrate fishes effectively. Flow characteristic measurements can provide quantitative information of the velocity distribution in fish ladders, which has strong correlation with the attraction of of fish. Recent research suggests that turbulence also has a large effect on fish migration. This is why obtaining flow information from well-defined turbulent flows, such as flow past cylindrical objects is the prime aim of these measurements. Particle Image Velocimetry (PIV) and Laser Doppler Velocimetry (LDV) have become the most popular and promising techniques for these types of non-contact measurements. PIV techniques are used to visualize and measure the flow characteristic in a selected area while LDV techniques are suited for point-based measurement. The works included in this thesis are reviewing PIV techniques previously used in fish movement related studies, LDV measurements both at upstream (bow wake) and downstream wake of cylindrical obstructions and finally Computational Fluid Dynamics (CFD) for validation of experimental measurements. The results find relatively acceptable agreement between CFD and experiments with some disparities.
5
Nyqvist, Daniel. "Atlantic salmon in regulated rivers : Migration, dam passage, and fish behavior." Doctoral thesis, Karlstads universitet, Institutionen för miljö- och livsvetenskaper, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-46903.
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Hydropower dams block migration routes and disrupt longitudinal connectivity in rivers, thereby posing a threat to migratory fish species. Various fish passage solutions have been implemented to improve connectivity with varying success. A well-functioning passage solution must ensure safe and timely passage routes that are used by a substantial portion of the migrating fish. In this thesis, I report the results from telemetry studies where the behavior and survival of migrating Atlantic salmon spawners, post-spawners and smolts have been evaluated in relation to hydropower dam passage. I evaluate downstream passage performance at dams with no passage solutions in the River Klarälven, and with simple passage solutions in in the Winooski River. In the River Ätran, I study both upstream- and downstream passage performance at a dam with sophisticated passage solutions based on the best available technology. In addition, I have studied the survival and behavior of post-spawners and hatchery-released smolts. A substantial portion of the spawners survived spawning and initiated downstream migration. Most males migrated downstream in autumn following spawning, whereas females tended to stay in the river until spring. For hatchery-reared smolts, early release was associated with faster initiation of migration and higher survival compared to late release. Multiple dam passage resulted in high mortality for both smolts and kelts. For smolts, dam passage, even with simple passage solutions, was associated with substantial delay and mortality. High spill levels were linked to high survival and short delay for downstream migrating salmon. The best available passage solution, which consisted of a nature-like fishway and a low sloping intake rack to guide fish to a bypass, resulted in rapid passage of a large portion of the adult migrants.
6
Jesuthasan, Suresh. "Two modes of cell movement in the zebrafish embryo : neural crest cell migration and epiboly." Thesis, University of Oxford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240465.
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Ordeix, Rigo Marc. "Fish migration in Mediterranean rivers: a case study of the fish pass assessment in Catalonia (NE Iberian Peninsula)." Doctoral thesis, Universitat de Lleida, 2016. http://hdl.handle.net/10803/396363.
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Pràcticament tots els peixos ibèrics d'aigües continentals migren clarament. La majoria són potamòdroms però també n’hi ha de diàdroms. Fan moviments migratoris extensos en el temps, més a mesura que disminueix la latitud, i varien entre els anys. Les seves migracions són molt importants al període de fresa i, gairebé tot l'any, per a alimentació i refugi. Per això, els dispositius de pas per a peixos haurien d’estar pràcticament sempre en funcionament.
Entre 2005 i 2010, es va dur a terme una avaluació preliminar de la connectivitat per als peixos dels rius de Catalunya mitjançant la inspecció directa de 95 dispositius de pas per a peixos. La majoria eren safareigs successius. Només hi havia dispositius de pas a l’11% dels obstacles i molts (el 61%) eren inadequats o amb un manteniment incorrecte.
Es va fer una anàlisi in situ de l'eficàcia de 10 dispositius aparentment adequats. L'estimació de les taxes de pas de moltes espècies eren, amb algunes excepcions, massa baixes i, a la majoria dels casos, aquests dispositius només facilitaven les migracions dels peixos amb més capacitat de superar obstacles o els individus de major talla.
L’avaluació complementària in situ d'una rampa per a peixos considerada eficaç a priori (índex ICF de 95) va mostrar que permetia el pas de tots els ciprínids autòctons. El període de fresa va ser el principal impulsor de la migració riu amunt, que també es va veure influïda per la disminució de cabal just després de puntes de cabal, un mínim de temperatura de l'aigua i les fases lunars menys lluminoses.Prácticamente todos los peces ibéricos de aguas continentales migran claramente. La gran mayoría son potamódromos pero también hay de diádromos. Realizan movimientos migratorios extensos en el tiempo, más a medida que disminuye la latitud, y varían entre los años. Sus migraciones son muy importantes en el periodo de freza y, casi todo el año, para alimentación y refugio. Así, los dispositivos de paso para peces deberían estar casi siempre en funcionamiento. Entre 2005 y 2010, se llevó a cabo una evaluación preliminar de la conectividad para los peces de los ríos de Cataluña mediante la inspección directa de 95 dispositivos de paso para peces. La mayoría eran estanques sucesivos. Sólo había dispositivos de paso en el 11 % de los obstáculos y muchos de ellos (el 61%) eran inadecuados o con un mantenimiento incorrecto. Se efectuó un análisis in situ de la eficacia de 10 dispositivos aparentemente adecuados. La estimación de las tasas de franqueo de muchas especies eran, con algunas excepciones, demasiado bajas y, en la mayoría de los casos, estos dispositivos sólo facilitaban las migraciones de los peces con mayor capacidad de superar obstáculos o los individuos de mayor talla. La evaluación complementaria in situ de una rampa para peces considerada eficaz a priori (índice ICF de 95) mostró que permitía el paso de todas los ciprínidos autóctonos. El periodo de freza fue el principal impulsor de la migración río arriba, que también se vio influida por la disminución de caudal justo después de puntas de caudal, un mínimo de temperatura del agua y las fases lunares menos luminosas.
Almost all Iberian freshwater fish clearly migrate. The great majority are potamodromous but there are also diadromous. Migratory movements are extensive in time, greater at lower latitudes, and vary over different years. Migrations take place particularly in the spawning period and throughout the year for feeding and refuge. Thus, fish passes would always be in operation. Between 2005 and 2010, a preliminary evaluation of river connectivity for fish in Catalonia was conducted through direct inspection of 95 devices. Most of them were pool passes. Fish passes were only present at 11% of river obstacles and many of these (61%) were inappropriate or poorly maintained. An in situ analysis of the effectiveness of 10 of these fish passes was carried out. The crossing rates estimated for many species, were, with few exceptions, too low and, in most cases, only fish with a high capacity for overcoming obstacles or the largest individuals succeeded in migrating. A complementary in situ assessment of a fish ramp considered effective a priori (ICF index of 95) showed that it allowed passage of all native cyprinids. The spawning period was a primary driver of upstream fish migration, which was also influenced by the decrease in river flow just after a peak flow, a minimum water temperature and less bright lunar phases. showed allow passage of all species. The spawning period was a primary driver of upstream fish migration, which was also influenced by a decrease in river flow just after a peak flow, a minimum water temperature and less bright lunar phases.
8
Wright, Gillian Victoria. "Impact of tide gates on diadromous fish migration in the UK." Thesis, University of Southampton, 2014. https://eprints.soton.ac.uk/376995/.
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Anthropogenic structures fragment river connectivity, impeding the migration of diadromous fish between essential habitats. Tide gates are used worldwide primarily for flood protection and land reclamation by closing under hydraulic pressure during the flood tide and opening when head differential is sufficient during the ebb. Although tide gates are known to decrease fish species richness, abundance, and movement, their impacts on the migration of ecologically and socioeconomically important diadromous fish in terms of passage efficiency and delay have not been reported elsewhere. Acoustic and passive integrated transponder telemetry revealed that passage efficiencies of upstream migrating adult brown trout, Salmo trutta (92%), and downstream migrating juvenile sea trout smolts (96 - 100%) and adult European eel, Anguilla anguilla (98%), were high at top-hung tide gates in two small English streams. However, these fish experienced delay at the gates (adult brown trout, median = 6.0 h; sea trout smolts, mean = 6.5 and 23.7 h; eels, mean = 66.2 h) when compared to migration through unimpeded reaches. The percentage of time the gates were closed and mean angle of opening were positively related to delay in both species and life stages. Diel periodicity also influenced delay for smolts and eels, which were more active at night. For adult trout, water temperature was positively associated with delay. Upstream and downstream water temperature and salinity were influenced by the temporal operation of the gates. Orifices installed in the gates did not mitigate delay for adult or juvenile trout. For adult eels, delay was decreased when an orifice was operational, although this coincided with more eels first approaching the gates when open, higher tides and greater saline intrusion upstream of the gates. When gates were open, fish would not pass immediately through, indicating the potential influence of a behavioural avoidance component. To examine the effect of hydrodynamics created by top-hung tide gates with different aperture sizes, wild sea trout smolt behaviour was observed by video cameras in an experimental flume at night. Avoidance responses occurred within an average of 1.4 fish body lengths upstream of the gate. Fish were more likely to exhibit avoidance (switch in orientation from negative to positive rheotaxis, increased tail beat frequency and/or retreat upstream) in the vicinity of a model gate with a smaller angle of opening and passage aperture. Overall, top-hung tide gates delayed the migration of diadromous fish, potentially increasing energy expenditure and predation risk. Delay was not decreased by orifices. Modifying or replacing top-hung tide gates with designs that allow them to open wider and for longer could reduce migratory delay and improve the environmental conditions that cause behavioural avoidance.
9
Pritt, Jeremy Joseph. "Fish Migration as an Ecosystem Linkage between Lake Erie and its Tributaries." University of Toledo / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1396277643.
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Lindbladh, Emma, and Johanna Eriksson. "Phenotypic correlates of spawning migration behaviour for roach (Rutilus rutilus) and ide (Leuciscus idus) in the stream Oknebäcken, Sweden." Thesis, Linnéuniversitetet, Institutionen för biologi och miljö (BOM), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-98343.
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Migration occurs among many animal species for the purpose of, among other things, finding food or to reproduce. Spawning migration is a form of migration that occurs among many fish species where they move to another site for reproduction. The movement can be obstructed by migration barriers like road culverts. Barriers to migration pose one of the greatest threats to biodiversity and ecosystem functions in freshwater. They impair the connectivity of watercourses and may prevent fish from improving reproductive success or completing their life histories altogether. There are both benefits and costs with migration, benefits such as increased survival for the adults and offspring, and costs such as increased energy consumption and increased mortality. The costs are often dependent on the morphological traits of the individual, like body shape and size. In this study, the spawning migration of two species of fish of the family Cyprinidae, ide (Leuciscus idus) and roach (Rutilus rutilus) was investigated. Few studies have been made on ide or on roach compared to other cyprinids and salmonids. This study might therefore enhance the overall knowledge of these two species. The overall aims of this project are to study and compare phenotypic correlates of spawning migration behaviour of ide and roach. The field studies were performed in Oknebäcken, Mönsterås (SE632310-152985), Sweden in March and April 2020. To describe the watercourse and define the location and characteristics of different potential migration barriers, a simplified biotope mapping method was used. The fish were caught in a hoop net and then measured, weighted, sexed, and injected with passive integrated transponder using the bevel down method. In order to register in stream movement of fish, reading stations with antennas were placed, at two locations upstream from the marking station and one downstream at the estuary. The sex ratio differed from the expected 1:1 with a majority of females for both species. This might be a result of fluctuations in survival of spawn coupled with different age-at-maturity between sexes. We found that individuals that arrived early to the stream were larger for both study species, as other studies also reported. Also, male ide was both larger and arrived before female ide. There might be an energy cost associated with early arrival to the stream and therefore, larger individuals arrive first. For roach, there was no difference in arrival time between the sexes although female roach were larger. There was no difference in the time spent in the stream between the species. For ide, females stayed for a longer period of time in the stream than males. However, the opposite was true for roach. This may be because male roach might benefit from more fertilization events when staying longer. There might therefore be a trade-off between the energy cost in staying in the stream and the increased fitness advantage in fertilization events. We found no correlation between any of the morphological traits and migration distance. However, since very few individuals were registered at the upstream reading stations, there might be an effect of migration barriers on the spawning migration. The mortality after spawning was higher for roach than for ide. For ide, a larger proportion of females than males died. For roach, individuals that arrived early was classified as alive to a greater extent than those who arrived late. Both similarities and differences between the species were discovered in this study which concludes that even closely related species might differ substantially from each other.
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Buchanan, Rebecca A. "Release-recapture models for migration juvenile and adult salmon in the Columbia and Snake Rivers using PIT tag and radiotelemetry data /." Thesis, Connect to this title online; UW restricted, 2005. http://hdl.handle.net/1773/6369.
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Bryson, J. Glen. "Aspects of the ecology of the intertidal fish fauna of the Forth Estuary, Scotland." Thesis, Heriot-Watt University, 1997. http://hdl.handle.net/10399/664.
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Fisher, Matthew Thomas. "Spatial and Temporal Patterns of Anadromous Fish Passage at Boshers Dam Vertical Slot Fishway on the James River, Richmond, Virginia." Available to VCU users at:, 2007. http://hdl.handle.net/10156/1830.
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Špaček, Jakub. "Úprava toku – návrh migrační cesty pro vodní faunu (rybího přechodu)." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-226144.
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This thesis describes the design of fish ladder on the river Mohelka near the village Chocnějovice. The first section describes the general characteristics of the river-basin and the selected section. It is written introduction to the design, construction and service of the fish ladder. For the task were developed two alternatives. These alternatives were described and compared each other. Included are the input and output data of the given structure modeling using HEC-RAS. The last part is then researched drawings to objects.
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Chovancová, Kateřina. "Studie rybích přechodů na Bečvě." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-226131.
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This master's thesis consists of three main parts. The first section describes some types of fish crossings and basic information of their design. There is also marginally described program HEC-RAS. The second part is about the Zuberská weir and Osek stage. I review here fish ladders according to the original drawings in the HEC-RAS and suggest possible options to address these passable fish crossings for the fish crew. The last section is devoted to Mikulenkov weir where the fish crossing has been completely removed. Here I propose a new fish ramp according to modern knowledge and applicable standards. I also review the proposed fish ramp in the HEC-RAS program in order to verify the hydraulic characteristics.
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Furey, Nathan B. "Migration ecology of juvenile Pacific salmon smolts : the role of fish condition and behaviour across landscapes." Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/58576.
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Migrations are utilized across taxa to exploit spatiotemporal variability across landscapes. The benefits of migrations are balanced with costs, and understanding the factors that limit migratory success is needed for proper management and conservation. Sockeye salmon (Oncorhynchus nerka) are of economic, cultural, and ecological importance and undergo downstream migrations from natal freshwater systems through rivers to the ocean as juvenile smolts. In this thesis, I describe a series of studies investigating the migration behaviour and survival of sockeye smolts emigrating from Chilko Lake, British Columbia, a large population that experiences poor survival in the Chilko River. First, field sampling and bioenergetics models were used to find that short-term feeding on smolts by bull trout (Salvelinus confluentus) in the Chilko River was extreme, not limited by cold temperatures, and resulted in greater exploitation of smolts than expected using traditional bioenergetic assumptions. Examining bull trout stomach contents revealed that consumed smolts had higher rates of infection by hematopoietic necrosis virus and Flavobacterium psychrophilum and were smaller than non-predated smolts. Through acoustic telemetry, I found that smolts traversing the upper Chilko River with higher densities of conspecifics experienced improved survival relative to smolts travelling at times when few smolts were migrating. Thus swamping predators can maximize survival. It is more difficult to conduct field studies in the coastal marine environment such as the Strait of Georgia, and even knowledge on migration routes and behaviour is limited. Aggregating telemetry data collected over ~10 years of research on sockeye and steelhead (Oncorhynchus mykiss) populations determined that contingents of both species exhibited westward lateral movements within the strait, consistent with predicted currents. Steelhead using the eastern migratory route experienced improved survival through the Strait to a location ~250 km further along the migratory corridor - a rare example of migration route impacting fitness. Individually, chapters advanced the fields of migration and feeding ecology and tested long-held ecological hypotheses. Important links were identified between smolt migration behaviour and/or survival and components of the movement ecology framework. This thesis has expanded our understanding of the factors influencing the migration of one of the largest sockeye populations in Canada.Forestry, Faculty of
Graduate
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Tummers, Jeroen Steven. "Evaluating the effectiveness of restoring longitudinal connectivity for fish migration and dispersal in impacted river systems." Thesis, Durham University, 2016. http://etheses.dur.ac.uk/11924/.
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In this study, the impact of anthropogenic in-stream structures on migration and dispersal of a variety of fish species was investigated. The effectiveness of attempted restoration of longitudinal connectivity in fragmented stream and river systems, through implementation of various fish pass designs, both technical and nature oriented, was evaluated for fish of varying age classes. The outcomes of this research are of importance for river management schemes that aim to restore degraded freshwater systems bound by legislation from the EU Water Framework Directive, which requires good connectivity and habitat quality within freshwater systems. Fish community composition in relation to effects of in-stream structures and habitat conditions was investigated on three degraded stream networks, so that future opportunities for longitudinal connectivity restoration could be identified. Differences in fish community composition above and below common types of structures were determined, whereby species richness and density per species showed greatest differences for flow manipulating culvert structures, especially pipe culverts. Obstacle effects on fish dispersal and migration, and the effectiveness of connectivity restoration - obstacle removal and design of various types of fish passes - on those same obstacles were evaluated using a variety of approaches. These included capture-mark-recapture of different life stages of a weak swimmer (European bullhead Cottus perifretum) and of a strong swimmer (brown trout Salmo trutta) tagged with passive integrated transponder (PIT) and/or visible implant elastomer (VIE), displacement studies of juvenile trout and radio telemetry of adult freshwater-resident and sea-going morphotypes of brown trout. Longitudinal connectivity for fish was shown to have improved post-restoration, exemplified by improved fish passage over the multiple structures in both directions, while permeability of unrestored structures remained low. The efficacy of a technical Larinier super active baffle fish pass, a widespread design in Europe, was assessed for upstream-migrating adult river lamprey. Situated next to a common Crump weir, the pass was designed to facilitate passage for a wide range of fish species. Over two migration seasons, with a variety of flow levels occurring in both, the pass was tested for efficacy before and after modification with studded tiles mounted on the inside wall. By using fixed PIT arrays, poor passage through the fish pass by river lamprey was shown before modification, and improved marginally post-modification. Acoustic telemetry identified direct passage over the weir to be two-fold higher than through the modified fish pass. In the context of the Water Framework Directive, there is a strong need to develop well-grounded fish passage criteria, not only for fish species with strong swimming capacity, but for a wide range of fish species and life stages. Ideally, all types of fishways should be critically assessed, in situ, to allow river managers to make more informed decisions on restoring fragmented stream systems.
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Yazgan, Tavsanoglu Ulku Nihan. "Zooplankton Adaptation Strategies Against Fish Predation In Turkish Shallow Lakes." Phd thesis, METU, 2013. http://etd.lib.metu.edu.tr/upload/12615354/index.pdf.
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In this study, the factors influencing zooplankton community structure in Turkish
shallow lakes were elucidated with four main approaches: (i) space-for-time
substitution for shallow lakes using snap-shot sampling in 31 lakes along a latitudinal
gradient(ii) in-situ mesocosm experiments in eleven lakes along a latitudinal gradient using three sets of artificial plants systems
(iii)&lsquo
Habitat Choice&rsquo
laboratory experiments mimicking a &lsquo
shallow littoral&rsquo
zone with plants and a &lsquo
deeper pelagic&rsquo
zone with sediments testing the response of Daphnia magna to predation cues
and (iv) long-term monitoring data (1997-2011) from two interconnected lakes. Snap-shot and long-term monitoring showed that eutrophication has a strong influence on the zooplankton community via increased fish predation, nutrient loading and salinization. Here too the zooplankton community shifted towards a smaller sized profile, especially in lakes located at lower latitudes. Moreover, The laboratory and in-situ mesocosm experiments revealed that under predation risk Daphnia preferred to hide near sediment instead of using submerged plants as a refuge. Accordingly, in-situ mesocosm experiments revealed a predation pressure induced size structure shift towards small-medium sized zooplankton and calanoid copepods. The long-term monitored lakes experienced (i) drought-induced water level drop, leading to increased salinity and eutrophication, and consequent anoxic conditions and fish kill
as well as (ii) biomanipulation in the downstream. Both conditions resulted in major reduction in the top-down control of fish and ultimate predomination by large sized Daphnia spp. Nevertheless, the excessive exploitation of lakes and ongoing warming entail Turkish shallow lakes to become more eutrophic, making this study indicative for the Mediterranean region.
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Wolfbrandt, Jeanette. "Beteende hos lekvandrande lax i Klarälven – utvärdering av en fiskfälla." Thesis, Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-34571.
Full textAbstract:
During the migration season in 2013 a study on spawning migrating salmon and the effect of water flow on the behavior was conducted of the salmon at the Forshaga hydropower station in the River Klarälven. The River Klarälven with its nine hydropower plants on the Swedish side, constituting migration obstacles for the migrating salmon. Fortum Generation AB has together with the County Administrative Board restored a salmon trap at the lowermost hydropower station in Forshaga, aiming at making it possible for the salmon to swim into the trap, and thereafter be transported by truck past the power plants and then continue their journey to the spawning grounds on their own. Unfortunately, it is believed that the trap does not work as well as it should. In this study, I focused on salmon position in relation to water flow and if the number of salmon that swam into the fish trap differed between salmon with previous experience of the trap (experienced) and salmon without experience (unexperienced). My results showed that there were significantly more inexperienced salmon that entered the trap than experienced salmon. The salmon, regardless of experience, chose a position where the flow was highest. To increase catches of salmon in the fish trap I suggest that one use more attraction water and keep the trap open more hours. My results should be of interest to managers as the trap efficiency has never been evaluated, and no earlier studies about the effect of salmon experience on trap efficiency exist.Vandringssäsongen 2013 genomfördes en studie på lekvandrande lax och hur vattenflödet påverkade laxens beteende vid Forshaga kraftstation i Klarälven. Klarälven med dess 9 vattenkraftverk på den svenska sidan utgör vandringshinder för den lekvandrande laxen. Fortum har tillsammans med Länsstyrelsen renoverat en laxfälla i det mest nedströms liggande kraftverket i Forshaga. Syftet med fällan är att laxen ska simma in i fällan till en uppsamlingsbassäng och därefter köras med lastbil förbi kraftverken, för att därefter fortsätta vandringen på egen hand. Fiskfällans effektivitet är ifrågasatt och man vet inte hur effektiv den är. I denna studie fokuserade jag på laxens ståndplats i relation till varifrån det huvudsakliga flödet kom, samt om antalet laxar som simmar in i fiskfällan skiljde sig mellan lax med tidigare erfarenhet av fällan (erfaren) och lax utan erfarenhet av fällan (oerfaren). Mina resultat visade att det var signifikant fler oerfarna laxar än erfarna laxar som simmade in i fällan. Laxen, oavsett erfarenhet, valde ståndplats där flödet var som högst. För att öka fångsterna av lax i fiskfällan skulle mer lockvatten och fler timmar då fällan är öppen kunna bidra med mer fångst. Denna studie borde vara av intresse för inblandade aktörer i laxens förvaltning eftersom fällans effektivitet aldrig utvärderats tidigare, och dessutom har man inte studerat om tidigare erfarenhet av en fälla påverkar laxen.
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Cuchet, Mathilde [Verfasser], Peter [Akademischer Betreuer] Rutschmann, Stefan [Akademischer Betreuer] Schmutz, and Laurent [Akademischer Betreuer] David. "Fish Protection and Downstream Migration at Hydropower Intakes : Investigation of Fish Behavior under Laboratory Conditions / Mathilde Cuchet. Gutachter: Peter Rutschmann ; Stefan Schmutz ; Laurent David. Betreuer: Peter Rutschmann." München : Universitätsbibliothek der TU München, 2014. http://d-nb.info/1069127558/34.
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Johansson, Ulf. "Vandring av vårlekande fisk och jämförelse av fångst mellan ryssja och strömöversiktsnät i Hammerstaån, Stockholms län." Thesis, Linköpings universitet, Institutionen för fysik, kemi och biologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-69515.
Full textAbstract:
During the last two hundred years many wetlands and streams in Sweden have been lowered to provide land for agriculture and forestry. Some of the coastal wetlands and streams probably served as spawning sites for certain species of fish in the Baltic Sea, but the present situation is not well known. As standardized methods to monitor fish in running waters are carried out during late summer or autumn, there is a need for methods to sample spring-spawning fish in these streams. The aim of this study was to survey the lower kilometer stretch of Hammerstaån in Stockholm, to investigate the extent to which the stream is used by spring-spawning fish. Furthermore, the study aims to evaluate a new type of survey fishing gill net called strömöversiktsnät (SÖN). This was done by comparing the catch of fish by SÖN with that of fyke nets. The comparison of the types of gear included number of fish caught, on a catch per unit effort (CPUE) basis, number of species and the size distributions. The study included 14 days with one gill net and one fyke net at two sites, in total 28 net-days. The inventory yielded in total seventeen species among which only trout (Salmo trutta), perch (Perca fluvitalis), roach (Rutilus rutilus), burbot (Lota lota), eel (Anguilla anguilla) and pike (Esox lucius) were previously known to occur. Six spawning species, smelt (Osmerus eperlanus), vimba bream (Vimba vimba), perch (Perca fluvitalis), roach (Rutilus rutilus), bream (Abramis brama) and white bream (Blicka bjoerkna) were caught in more than 60 individuals, which was set as a limit for comparisons of size distributions. There was no significant difference in CPUE between SÖN and fyke nets. Also length distribution did not differ between SÖN and fyke nets except for the species perch and white bream were the nets caught significant smaller perch and bigger white bream than the fyke nets. The results show that investigations with SÖN or fyke nets during springtime can be of great importance to increase our knowledge about spring-spawning fish in Swedish streams and the coastal areas of the Baltic Sea.
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Huusko, R. (Riina). "Downstream migration of salmon smolts in regulated rivers:factors affecting survival and behaviour." Doctoral thesis, Oulun yliopisto, 2018. http://urn.fi/urn:isbn:9789526217840.
Full textAbstract:
Abstract Atlantic salmon is one of the most widely known migratory fish species whose populations have declined because of hydropower installations. Attempts have been made to preserve salmon stocks in regulated rivers by building fishways for adult fish migrating upstream, but downstream migration of salmon smolts has been almost totally ignored. Instead, captive breeding programmes and extensive stocking of hatchery-reared salmon smolts have been initiated to compensate for highly reduced natural production and to maintain salmon yields. In recent decades, demands to reduce the environmental effects of hydropower production, together with public awareness of decreasing recapture rate and yield of stocked salmon, have increased calls for rebuilding wild salmon stocks in rivers modified for hydropower production. As a consequence, survival of salmon smolts during downstream migration and the effects of hatchery rearing and stocking methods are now research topics of high importance. This thesis examined the need for modifications to the current standard hatchery rearing and release methods, determined the effects of commonly used tagging methods and investigated the impacts of river regulation on the survival and behaviour of downstream migrating smolts by applying telemetry techniques. Modifications made to the standard rearing processes noticeably affected the physiology, behaviour and survival of salmon smolts. In addition, the timing of release was shown to be a key factor for the survival of released smolts. Therefore, comprehensive rearing of smolts, and improving current release methods, especially to match the timing of release to the migration window of wild smolts, are high priorities. Observations in semi-natural environments indicated that commonly used tagging methods had only slight effects on the survival of smolts, so they can be freely used to examine smolt performance. However, more information on rearing and stocking processes and tagging methods is still needed to fully verify the present findings in field conditions. Finally, increasing smolt survival during their downstream migration in regulated rivers is an urgent issue, as survival of smolts was found to be six-fold lower within a river section with five hydropower dams than in a corresponding section of a free-flowing river. In future salmon stock rebuilding actions in regulated rivers, safeguarding downstream migration of smolts should be considered as an equally important issue to safeguarding upstream migration of spawnersTiivistelmä Lohen kannat ovat taantuneet jokien vesivoimarakentamisen seurauksena. Rakennettujen jokien katkenneita vaellusyhteyksiä on pyritty avaamaan rakentamalla kalateitä ylävirtaan vaeltavia aikuisia lohia varten, mutta alavirtaan vaeltavat kalat ovat jääneet lähes huomiotta. Samanaikaisesti kalankasvatus ja massiiviset poikasistutukset ovat olleet suuressa roolissa lohikantojen ylläpitämisessä. Viime vuosikymmeninä istutustulosten heikkeneminen ja toisaalta yleisemminkin lisääntynyt kiinnostus ympäristöasioita kohtaan ovat lisänneet halukkuutta palauttaa lohikantojen luontaista lisääntymistä rakennettuihin jokiin. Tämän seurauksena kasvatus- ja istutusmenetelmien vaikutukset lohen poikasiin sekä vaelluksen onnistuminen rakennetuilla joilla ovatkin nousseet tärkeiksi tutkimusaiheiksi. Väitöskirjani tavoitteena oli selvittää telemetriatekniikoiden avulla nykyisin käytössä olevien kasvatus- ja istutusmenetelmien, yleisesti käytössä olevien kalamerkintätapojen sekä joen patoamisen vaikutusta lohen vaelluspoikasten jokivaelluksen onnistumiseen. Poikaskasvatuksen aikaiset muutokset vaikuttivat vaelluspoikasten kokoon, fysiologiaan ja käyttäytymiseen. Lisäksi kasvatuskäytäntöjä muuttamalla saatiin tuotettua enemmän luonnonpoikasia muistuttavia istukkaita kuin perinteisellä kasvatusmenetelmällä. Istutusajankohta osoittautui myös tärkeäksi selittäjäksi vaelluspoikasten eloonjäännissä. Kasvatusmenetelmien muuttaminen paremmin luonnonolosuhteita vastaaviksi ja istutusajankohdan sovittaminen luonnonpoikasten luonnolliseen vaellusaikaan olisivat tarpeellisia muutoksia nykyisiin kasvatus- ja istutuskäytäntöihin. Yleisesti käytössä olevat kalamerkintätavat soveltuvat vaelluspoikastutkimuksiin, sillä eri merkintämenetelmien vaikutukset vaelluspoikasten kasvuun ja käyttäytymiseen olivat vähäisiä kokeellisissa olosuhteissa tehdyssä tutkimuksessa. Lisää tietoa kuitenkin tarvitaan kasvatus- ja istutusmenetelmien sekä merkintätapojen vaikutuksista luonnonolosuhteissa. Lohen vaelluspoikasten selviytymistä alasvaelluksesta rakennetuilla joilla tulee parantaa merkittävästi, sillä vapaasti virtaavassa joessa vaelluspoikasten selviytymisen havaittiin olevan kuusinkertainen rakennettuun jokeen verrattuna. Lohikantojen palauttamishankkeissa on palaavien aikuislohien kutuvaelluksen rinnalla kiinnitettävä erityistä huomiota myös vaelluspoikasten jokivaelluksen onnistumiseen
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Killinger, Gregory M. "Movement and survival of chinook salmon fry stocked in a stream with natural barriers to anadromous fish migration." Thesis, Virginia Tech, 1994. http://hdl.handle.net/10919/42100.
Full textAbstract:
This study examined the movement, habitat utilization, growth, and survival of hatchery incubated chinook salmon (Oncorhynchus tshavvytscha) fry stocked above a barrier falls on the Indian River, Chichagof Island, southeast Alaska. The Indian River contained significant potential salmonid rearing habitat, but was devoid of anadromous fish upstream of the barrier falls near tidewater. Approximately 50,000 and 260,000 chinook fry were stocked into Indian River in 1986 and 1988, respectively. The stream was divided into reaches which were stocked with equal numbers of fry. In 1988, fry also were stocked into beaver ponds connected to the stream. Each group of fry contained coded-wire tagged individuals, identified by stocking location.
Fry movement was almost entirely downstream, with a substantial emigration during a spring flood immediately after the 1988 stocking. Most emigrating fry had been stocked in the lower stream section.
Master of Science
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Veenstra, Arno. "Putting behavioral assays on fish to the test: Are sociality and scototaxis trials relevant in the wild?" Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-172154.
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Animal behavior has become a frequently used tool in modern ecology and ecotoxicology, where laboratory behavioral traits are recognized as sensitive endpoints for assessing natural behavior or non-lethal effects of pollutants on animals. Within these research fields, behavioral traits measured in laboratory environments have been used to formulate predictions of ecological consequences that accompany specific behavior. However, the predictive power of behavioral traits measured in simplified laboratory environments for complex natural aquatic ecosystems has been questioned. In this study, I have examined to what extent behavioral changes, noted in laboratory settings in response to chemical stressors (an anxiolytic drug) or visual cues of black and white bottom substrates, are also expressed in the wild. In my first experiment, I scrutinized whether reduced social behavior previously shown to occur in the lab for European perch (Perca fluvatilis) in response to oxazepam also occurs within a natural lake subjected to oxazepam. The in situ behavior was measured using high temporal resolution (3 sec) acoustic telemetry. In my second experiment, I assessed if the Atlantic salmon’s (Salmo salar) preference for black bottom substrates (scototaxis) in laboratory assays could be utilized for guiding migrating Atlantic salmon in situ. I show that: i) Oxazepam does not affect the social (association) behavior or the social network structure of perch in natural settings, in contrast to laboratory-based predictions; ii) Atlantic salmon show a preference for black bottom substrates both in laboratory- and natural environments. My study with oxazepam underlines that abiotic environmental factors and collective decision making in-situ, can override the anti-social behavioral effects of oxazepam on perch in a natural Lake. However, there seems to be potential in using laboratory behavioral assays to predict behavior in the wild, given that there is a tendency for migrating salmon to follow black bottom substrates both in laboratory environments and in streams.
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Santos, Lúcio. "Conectividade de hábitat em bacias hidrográficas : simulações com múltiplas barragens e hierarquia de segmentos para conservação." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2011. http://hdl.handle.net/10183/117132.
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A biodiversidade dos rios brasileiros encontra-se sob severa ameaça, em razão da fragmentação e perda de hábitat que os barramentos representam. Até o presente, os aproveitamentos hidrelétricos têm seu licenciamento ambiental condicionado a análises de impacto locais, sem avaliação dos impactos cumulativos de múltiplas barragens em uma bacia hidrográfica, com relação à conservação da diversidade da ictiofauna. Estudos anteriores para subsídio de licenciamento de múltiplas barragens na bacia Taquari-Antas (RS) propuseram cenários alternativos de conservação (número e posição de barragens), quando ainda não havia métricas de conectividade dendrítica desenvolvidas. Entre os problemas identificados naqueles estudos figuram a quantificação dos efeitos cumulativos das barreiras sobre a conectividade da bacia, o estabelecimento de áreas prioritárias para conservação e a influência do número e da posição das barreiras na conservação da biodiversidade aquática em uma bacia. Avaliamos a aplicação de conectividade para mensuração de impactos cumulativos de fragmentação de bacias hidrográficas através de índices de conectividade dendrítica recentemente propostos. Propomos um método genérico e replicável para analisar quantitativamente os efeitos de sucessivos barramentos em relação à conectividade dos hábitats aquáticos em processos de migração e dispersão de peixes em bacias hidrográficas. Utilizamos simulações de cenários de múltiplos barramentos para a avaliação. Propomos também uma sistematização para a simulação de múltiplos barramentos. Além disso, hierarquizamos áreas para conservação por conectividade, aplicamos as novas métricas de conectividade a estudos anteriores e demonstramos casos de cenários de alta conectividade com outras implicações na conservação. Discutimos o amadurecimento do método para aplicação em licenciamento ambiental e planejamento de conservação, bem como limitações atuais e perspectivas para trabalhos futuros.Biodiversity of Brazilian rivers is nowadays seriously threatened due to fragmentation and habitat loss that impoundments represent. Up to now, hydroelectric power plants have their environmental licensing processes conditioned to local impact analysis, with no evaluation of cumulative impacts of multiple dams in a watershed landscape on the conservation of the integrity of ichthyofauna. Former studies for supporting environmental licensing processes of multiple hydroelectric dams in the Taquaria-Antas basin (RS, Brasil) proposed alternative conservation scenarios (number and position of barriers), in a time when there were no dendritic connectivity metrics developed. Among the problems identified at that time, we point quantification of cumulative effects of multiple barriers on the drainage connectivity, detecting prioritary areas for conservation and detecting the influence of the number and position of the barriers in the catchment for best conservation of aquatic biodiversity. We evaluated the application of connectivity for quantifying the impacts of fragmentation in hydrographic basins through recently proposed indexes. We proposed a replicable and generic method for quantifying the effects of successive impoundments in relation to aquatic habitat connectivity in ecological processes of migration and dispersal of fishes in hydrographic basins. We used multiple barriers scenarios simulation in order to perform the assessments. We also propose a way of systematizing multiple barriers simulations. Moreover, we rank areas for conservation by connectivity, apply the new connectivity metrics on former studies and demonstrate cases of high connectivity scenarios with other implications on conservation. We discuss maturing the method for application on environmental licensing and conservation planning as well as current limitations and perspectives for future studies.
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Svensson, Rebecka. "Temperatur- och flödespåverkan på aspens (Leuciscus aspius) lekvandring i Fyrisån och Örsundaån, Uppland." Thesis, Uppsala universitet, Institutionen för biologisk grundutbildning, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-383797.
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Interconnected freshwater habitats are essential for many fish populations, which allow fish to migrate between areas to fulfil their life-cycle and maximize their fitness. Currently, such populations are negatively affected by human habitat exploitation. As a result, the biodiversity in freshwater ecosystems is decreasing. In this study, I use data from surveys of two Asp (Leuciscus aspius) populations in Uppland to see how a representation of day length, water temperature and water current influence their spawning migrations. I also determine the difference in timing of migration between males and females, and if the individual body size matters. I found that day length, water temperature and water current affect the migratory behavior of Asp. I also found a significant difference in migratory timing between males and females, where males on average arrive 5-6 days earlier than females to spawning areas.
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Arenas, Amado Antonio. "Development and application of a mechanistic model to predict juvenile salmon swim paths." Diss., University of Iowa, 2012. https://ir.uiowa.edu/etd/2813.
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Utility companies and regulatory agencies are interested in understanding juvenile salmon swimming patterns as they approach hydropower dams because it can allow them to assess fish bypass efficiency and conduct fish survival studies. A model capable of predicting juvenile salmon swim paths can assist in the design of fish bypasses and diversion structures. This thesis presents a mechanistic model tailored to simulate swimming patterns of juvenile salmon swimming in forebays, tailraces, and free-flowing rivers. The model integrates information on juvenile salmon behavior at both field and laboratory scale and literature on juvenile salmon swimming capabilities.
Simulated fish swim paths are determined by solving Newton's Second Law. Most of the model parameters are represented by probability distributions. Behavioral responses are triggered for the most part by the flow acceleration and pressure. The model uses conditional probability distributions of thrust magnitude and direction, given flow acceleration. Simulated fish select a swimming direction referenced to the flow velocity vector. To consider juvenile salmon's tendency to coast with the flow, the model intersperses periods of active swimming and gliding. Chinook salmon measured swim paths were analyzed. The flow variables at the fish locations were obtained from CFD simulations. Juvenile salmon mean thrust was determined from solving Newton's Second Law at every measured location. Results show that as flow acceleration increases, the juvenile salmon average thrust increases and the probability of gliding decreases. Chinook salmon tend to migrate tail-first as flow acceleration increases. For the flow accelerations of 5x10-4 m/s2 and 1x10-2 m/s2, approximately 85% and 95% of the analyzed fish migrated tail-first, respectively. The model capacity to predict fish migration route selection, fish-like trajectories, and residence times was tested at two hydropower dams. On average, migration routes were predicted with 17 percent of relative error. Model predictions for fish average residence times were within 10 percent of measured values.
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Bakala, Filip. "Revitalizace vybraného úseku vodního toku." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-226147.
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This thesis deals with revitalization of the selected part of river Drevnice. Main scopes of the work are proposals of fish passages through migration barriers. The work is conceived on four levels. The first of them is dealing with the general characteristics of selected segment and with description of objects on watercourse. The second level is dealing with revitalization, where the basic information about migration and efficiency of fishes are described. In this chapter basic distribution of fish ladders is included. In third part, which is the most comprehensive, I design a boulder fish ramp and bypass channel. The last chapter contains drawings documentation of watercourse Drevnice and my own proposed revitalization elements.
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Few, Janet Mary. "Faith, fish, farm or family? : the impact of kinship links and communities on migration choices and residential persistence in North Devon 1841-1901." Thesis, University of Exeter, 2009. http://hdl.handle.net/10036/88193.
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From Ravenstein onwards, historians considering the causes of migration have stressed the importance of economic factors. Whilst work related issues have been shown to prompt the majority of migrations, the role of extended kin deserves further attention. Plakans and Wetherell found that, the ‘placing [of the] domestic group within a larger kin context’, seen as the next logical research step as long ago as the 1970s, was an issue that remained largely unaddressed in 2003. Here the impact of the extended family, on migration decisions and the likelihood of residential persistence, is investigated. Evidence for community cohesion has been sought and kinship links have been investigated; both have been found to influence the residential patterns of individuals. This research has revealed that, whilst economics may provide the impetus for a move, cultural factors and the role of non-resident kin played a far greater part in the decision to migrate, or not, than most previous studies have acknowledged. It has been shown that, although kinship impacted upon both, reasons for emigration were very different from those for migration. The substantial role played by religious belief, not only as a motivation for the emigration of extended family groups, but also as an issue influencing the choice of destination, is a particular feature of the findings of this study. In 1994, Pryce and Drake were ‘making a strong plea for the adoption of rigorous intellectual approaches in migration research’ and the methods used here address this appeal. A technique of total reconstruction and longitudinal tracing has been employed in order to investigate the inhabitants of three small areas of North Devon. A comprehensive range of sources has been used and an in-depth examination of exemplar migrants and the residentially persistent, has allowed possible motivations to be scrutinised. In this way, the details of the structures and processes observed become clearer. In the context of family reconstitution, Barry Reay wrote of ‘a dearth of such studies of nineteenth-century England’ and it is intended that the methods used in this research will facilitate a wider understanding of the factors that motivated migrants in Victorian rural England. Whilst considering the influences of kin and community on migration patterns in the three study areas, the relative roles of other factors have been taken into account. It has been necessary to look at economic patterns and to investigate how, for example, farming and fishing, and any nineteenth century changes therein, affected the lives of the inhabitants. In an area where, and at a time when, non-conformist religion took a particular hold, the effect that the faith of these individuals had on their decisions to move, or stay put, has been assessed. Thus, the issues of faith, fish, farm and family are all borne in mind when studying the motivations for the migration decisions of the inhabitants of the three settlements.
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Nordin, Jonathan. "Highway To Hell: Can a bubble barrier guide descending salmonid kelt to safety?" Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-174689.
Full textAbstract:
Loss of connectivity in riverine systems due to construction of hydropower dams has resulted in a worldwide decline of anadromous salmonid species such as Atlantic salmon (Salmo salar L.) and sea trout (Salmo trutta L.). The future of these species depend on the presence of available spawning habitat in freshwater river systems. Modern research and mitigation efforts mainly focus on ensuring a successful upstream passage past dams e.g. fish ladders. Atlantic salmon and sea trout are iteroparous, and are thus able to spawn repeatedly during their lifetime. Individuals surviving upstream migration and spawning generally face a hazardous journey back to their marine feeding grounds. In this large scale natural field study I evaluate the possibility of using a bubble barrier as a non-physical structure to guide downstream migrating kelt past the turbines at a large hydropower station in northern Sweden. Results from this study clearly show that kelt effectively can be diverted using a bubble barrier in daylight conditions with a mean water velocity of 1.1 m s-1 (p=0,01). From a fishway managers perspective, increasing survival of salmonid kelt is a substantial step towards achieving a viable population with increased numbers of repeat spawners and large individuals. This study presents new results in a sparsely explored subject; the diversion of post-spawn salmonid migrants using non-physical barriers.
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Van, Der Waal Zelda. "When fish are not poisson : modelling the migration of Atlantic salmon (Salmo salar) and sea trout (Salmo trutta) at multiple time scales." Thesis, University of Newcastle upon Tyne, 2014. http://hdl.handle.net/10443/2420.
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Migratory species undertake prolonged seasonal journeys; monitoring these movements is challenging but can sometimes be achieved by observations that taken locally and, ideally, using remote methods. Amongst the best known examples of migrating fish in Europe, are Atlantic salmon (Salmo salar) and sea trout (Salmo trutta) that migrate between river and seawater. Characteristics of habitat suitability, feeding opportunities, predation, as well as salmonid sensitivity and needs, vary throughout successive stages of their anadromous life cycle. Since the marine stage is the longest but is also challenging to monitor, in-river fish counters are of increasing importance in understanding salmonid patterns in abundance. The original contribution of this thesis lies in the use of modelling techniques to investigate salmonid migration, based on temporal observations produced by an electronic fish counter triggered by salmonid passage, as they return to spawn in the River Tyne. Small scale observation revealed seasonal differences; aggregation behaviour intensified during the middle of the migration season, and explanatory covariates varied in both their effect size and relevance to salmonid abundance. At the population scale, migration was highly driven by annual periodicity, abundance increased with river temperature and there was an NAO effect with a four year lag, underlining the importance of marine conditions to parent population and/or post-smolts. Differences between distinct populations of S. salar and S. trutta appeared related to a species-specific annual periodicity and oceanic conditions as salmonids return (more so for S. salar). State-space models suggested a complex demographic structure for the two species. There was a species identification learning curve that affected the data by 2007. A classification algorithm determined that observations are more likely to be S. salar for larger signal amplitude, within a higher river flow and earlier in the year; characteristics were too similar between the two species to reach a useful classification success rate (69%). The project overall suggests specificities relating to both species and age-class that cannot be addressed in depth with the collected data; emerging limitations and recommendations are discussed.
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Sandberg, Marcus. "Pilot study: Is it possible to get Clown loach, Chromobotia macracanthus, ready to spawn in aquariums?" Thesis, Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-30604.
Full textAbstract:
The clown loach Chromobotia macracanthus, is a well known species in ornamental fish circuits although the knowledge about it in its wild environment today is limited. The outtake of 50 million juveniles every year may drive the population into a collapse and it might be necessary to breed clown loaches in captivity to lower the pressure in wild stocks. This has not yet been accomplished without hormone treatment. The aim of the present study is to find out if it is possible for C. macracanthus to prepare for spawning in captivity without the use of hormones. The study was set up according to documentation about the wild conditions simulating the migration prior to spawning from greater rivers and swamps to smaller streams upriver. Although the experiment did not result in spawning it is believed that egg production took place according to criteria for identifying sexually mature fish ready to spawn. If so it would have resulted in the fish retaining or reabsorbing the eggs since they were not laid. A surprising result which tells us it would not be unusual with egg production in C. macracanthus in aquariums around the world.
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Duncan, Murray. "The genetic stock structure and distribution of Chrysoblephus Puniceus, a commercially important transboundary linefish species, endemic to the South West Indian Ocean." Thesis, Rhodes University, 2014. http://hdl.handle.net/10962/d1011868.
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Chrysoblephus puniceus is an over-exploited linefish species, endemic to the coastlines off southern Mozambique and eastern South Africa. Over-exploitation and habitat loss are two of the biggest threats to the sustainability of fisheries globally. Assessing the genetic stock structure (a prerequisite for effective management) and predicting climate related range changes will provide a better understanding of these threats to C. puniceus which can be used to improve the sustainability of the fishery. Two hundred and eighty four genetic samples were collected from eight sampling sites between Ponta da Barra in Mozambique and Coffee Bay in South Africa. The mitochondrial control region and ten microsatellite loci were amplified to analyse the stock structure of C. puniceus. The majority of microsatellite and mtDNA pairwise population comparisons were not significant (P > 0.05) although Xai Xai and Inhaca populations had some significant population comparisons for mtDNA (P < 0.05). AMOVA did not explain any significant variation at the between groups hierarchical level for any pre-defined groupings except for a mtDNA grouping which separated out Xai Xai and Inhaca from other sampling sites. SAMOVA, isolation by distance tests, structure analysis, principle component analysis and spatial autocorrelation analysis all indicated a single population of C. puniceus as being most likely. The migrate-n analysis provided evidence of current driven larval transport, with net migration rates influenced by current dynamics.Two hundred and thirty six unique presence points of C. puniceus were correlated with seasonal maximum and minimum temperature data and bathymetry to model the current distribution and predict future distribution changes of the species up until 2030. Eight individual species distribution models were developed and combined into a mean ensemble model using the Biomod2 package. Winter minimum temperature was the most important variable in determining models outputs. Overall the ensemble model was accurate with a true skills statistic score of 0.962. Binary transformed mean ensemble models predicted a northern and southern range contraction of C. puniceus' distribution of 15 percent; by 2030. The mean ensemble probability of occurrence models indicated that C. puniceus' abundance is likely to decrease off the southern Mozambique coastline but remain high off KwaZulu-Natal. The results of the genetic analysis support the theory of external recruitment sustaining the KwaZulu Natal fishery for C. puniceus. While the high genetic diversity and connectivity may make C. puniceus more resilient to disturbances, the loss of 15 percent; distribution and 11 percent; genetic diversity by 2030 will increase the species vulnerability. The decrease in abundance of C. puniceus off southern Mozambique together with current widespread exploitation levels could result in the collapse of the fishery. A single transboundary stock of C. puniceus highlights the need for co-management of the species. A combined stock assessment between South Africa and Mozambique and the development of further Marine Protected Areas off southern Mozambique are suggested as management options to minimise the vulnerability of this species.
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Ahlbeck, Ida. "Living in a predation matrix : Studies on fish and their prey in a Baltic Sea coastal area." Doctoral thesis, Stockholms universitet, Systemekologiska institutionen, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-75238.
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This thesis was written within the framework of a biomanipulation project where young-of-the-year (YOY) pikeperch (Sander lucioperca) were stocked to a Baltic Sea bay to improve water quality through a top-down trophic cascade. The aim of my doctorial studies was however focused on a broader ecological question, namely predation (the main driving force in a biomanipulation). Hence, this thesis consists of four papers where we study the interactions between predator and prey using fish and zooplankton and how these interactions can be measured. In paper I we evaluated the performance of different diet analysis methods by individual based modelling and found that when having a nutritional gain perspective, mass based methods described diets best. Paper II investigated how the explorative, foraging and anti-predator behaviour of the YOY pikeperch used for stocking were affected by their rearing environment (pond vs. tank rearing). The more complex and varied environment in the semi-natural ponds seemed to promote a more flexible and active behaviour, better equipping young fish for survival in the wild. For paper III we studied the diel vertical migration in the six copepodite stages of the zooplankton Acartia spp. and Eurytemora affinis in relation to fish biomass, phytoplankton abundance and temperature. Both species migrated and in addition showed increased migration range with size within species, indicating evasion from visual predators. Paper IV addressed the movement of littoral Eurasian perch (Perca fluviatilis) via stable isotope signatures (13C and 15N) and body condition. We found clear indications of sedentarity and intra-habitat dietary differences. Interactions between predators and prey are complex and affected by both physiological and environmental characteristics as well as behavioural traits. The results in this thesis suggest that different species and even different life stages pursue different strategies to survive.At the time of doctoral defense, the following papers were unpublished and had a status as follows: Paper 1: Submitted. Paper 2: In press. Paper 4: Submitted.
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Carvajal, Fernando Marcelo. "Phylogeny and population genetics of the fish performing the largest migration known in freshwater, the Amazonian catfish "Brachyplatystoma rousseauxii" : revelations from the upper Madera Basin." Thesis, Montpellier 2, 2013. http://www.theses.fr/2013MON20269.
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Le plateado ou dorado - Brachyplatystoma rousseauxii (Pimelodidae, Siluriformes) est un grand poisson-chat Amazonien d’intérêt commercial, qui présente un des cycles de vie les plus surprenants et énigmatiques, avec la plus grande migration connue en eaux douces, entre l’estuaire de l'Amazone et les têtes de fleuves en Amazonie occidentale. Le but de ce travail était de déterminer, au niveau moléculaire, la position phylogénétique du plateado dans la famille Pimelodidae ainsi que sa structure génétique dans le Haut Madera (Villa Bella–VB, Cachuella Esperanza–CE, Puerto Maldonado–PM, Rurrenabaque–RU, Puerto Villarroel–PV) et ouest de l'Amazonie (Iquitos–IQ) bassins (Bolivie et Pérou). Les relations phylogénétiques ont été définies par une analyse du maximum de vraisemblance (ML) des séquences nucléotidiques de deux gènes mitochondriaux (Région de Contrôle–RC, ~ 900 pb, 32 taxons; Cytochrome Oxydase 1-CO1, ~ 650 pb, 61 taxons), et d’un gène nucléaire (F-reticulon4–RTN4, ~ 1700 pb, 38 taxons). La structure génétique des populations a été évaluée par le polymorphisme de longueur de neuf microsatellites (284 inds) et par les variations de séquence de la RC (461 inds + 45 en provenance du Brésil, disponibles dans GenBank). Les variations de fréquences des microsatellites ont été utilisées pour identifier les unités panmictiques (clusters) les plus probables dans l'ensemble des données, à travers une approche bayésienne (BAPS), après avoir démontré une déviation significative à l'équilibre de Hardy-Weinberg (HWE) quand l’ensemble des données étaient analysé comme faisant partie d’une seule unité. L’analyse phylogénétique concaténée (ML) a montré que la famille Pimelodidae était un groupe monophylétique. Les résultats les plus notables de la phylogénie sont la monophylie peu soutenue (77%) de la tribu Brachyplatystomatini et la non-monophylie des Brachyplatystoma. Seul le sous-genre Malacobagrus (B. rousseauxii + (B. filamentosum + B. capapretum)), défini morphologiquement, s’est avéré monophylétique. Ces résultats suggèrent que le genre Brachyplatystoma pourrait contenir Platynematichthys ou pourrait être limité au sous-genre Malacobagrus.L'analyse des microsatellites sur l'ensemble des échantillons (ouest Amazone + haut Madera) a montré un écart significatif á la panmixia, ainsi que sur l'ensemble des échantillons du haut Madera. A la lumière de ces résultats, l’approche bayésienne a été développée, montrant qu'au moins trois clusters (1, 2, 3) sont présents dans les bassins du haut Madera et de l'ouest de l'Amazone, avec des répartitions qui se chevauchent partiellement. En parallèle á l'identification des clusters, il a été mis en évidence une différence significative au sein de B. rousseauxii entre l’ouest de l'Amazonie et le haut Madera bassin. L'analyse généalogique (ML) des séquences de la RC a montré une topologie en peigne, sans groupe d'haplotypes montrant une histoire commune. En revanche, l'analyse des fréquences haplotypiques a révélé l’existence de 4 haplogroupes, liés à la géographie. Un haplogroupe a été identifié le long de l'axe principal de l’Amazonas-Solimões (Belem-Brésil et Iquitos-Pérou) et 3 autres dans le haut Madera (VB; CE+MD; RU+PV), organisés selon une tendance aval - amont. Ainsi, nous observons d’un coté 3 populations (clusters) avec une distribution géographique partiellement chevauchante, et de l’autre quatre haplogroupes positionnés selon une logique géographique. Le scenario le plus probable implique un comportement de homing des individus du cluster 1 (homing à l’échelle des grands sous-bassins), qui préfèrent ou tendent à retourner dans le sous-bassin du Madera. Les 3 populations coexisteraient alors dans le haut Madera en se reproduisant à des périodes (phénologie) ou à des endroits différents (ségrégation spatiale). Enfin, les résultats sont discutés à la lumière des résultats précédemment publiés dans le bassin de l'Amazone et des menaces qui pèsent sur l'espèce dans le bassin du MaderaThe Plateado or Dorado - Brachyplatystoma rousseauxii (Pimelodidae, Siluriformes) is a commercial migratory catfish species with one of the most surprising and enigmatic life histories in the Amazon basin, involving the largest migration known for a freshwater species, between the estuary and the head waters in the Andean piedmont. The aim of the present work was to determine the molecular phylogenetic position of the Plateado in the Pimelodidae family and its population genetic structure in the Upper Madera (Villa Bella – VB, Cachuella Esperanza – CE, Puerto Maldonado – PM, Rurrenabaque – RU, Puerto Villarroel - PV) and Western Amazon (Iquitos - IQ) basins (Bolivia and Peru). The phylogenetic relationships were defined through a Maximum Likelihood (ML) analysis of nucleotide sequences of two mitochondrial (Control Region – CR, ~ 900 pb, 32 taxa; Cytochrome Oxidase 1 – CO1, ~ 650 bp, 61 taxa), and a nuclear fragment (F-reticulon4 - RTN4, ~1700 bp, 38 taxa). The population genetic structure was evaluated through the length polymorphism of nine microsatellites (284 inds) and CR sequence variations (461 inds + 45 from Brazil available in GenBank). Microsatellites frequencies variations were used to identify through a Bayesian approach (BAPS) the most probable panmictic units (clusters) in the whole data, after previous demonstration of a deviation to Hardy-Weinberg Equilibrium (HWE). The ML phylogenetic concatenated analysis showed the Pimelodidae family as a monophyletic group, with the genera Phractocephalus and Leiarius as basal lineages. The most notable results in the phylogeny were the not well-supported monophyly (77%) of the tribe Brachyplatystomatini and the non-monophyly of Brachyplatystoma. Only the morfologically defined subgenus Malacobagrus (B. rousseauxii + (B. filamentosum + B. capapretum)) was recovered as monophyletic. These results suggest that Brachyplatystoma could contain Platynematichthys or be restricted to the subgenus Malacobagrus, and the other species be related to distinct (earliest) genera, in agreement with another study carried out in parallel with other markers.Microsatellite analysis of the whole data (Western Amazon + Upper Madera) showed a significant departure of the HWE expectations, as well as the analysis of the whole data from the Upper Madera region. In the light of these results, the Bayesian approach has been implemented, showing that at least three clusters (1, 2, 3) are present in the Upper Madera and Western Amazon basins with partial overlapping distribution.To the margin of the cluster identification, it was evident the significant difference between Western Amazon (Iquitos region) and the Upper Madera basin.The genealogical analysis (ML) of the CR sequences showed a generalized comb-like topology without group of haplotypes with common ancestry. On the other hand, CR frequency analysis showed the conformation of four haplogroups associated to geography. One haplogroup was identified along the main axis of the Amazonas-Solimões, from Belem (Brazil) to Iquitos (Peru), and three other haplogroups were observed in the Upper Madera basin (VB; CE+PM; RU+PV), positioned in a downstream - upstream pattern.Hence, we observed on the one hand three genetic populations (clusters), distributed in partially overlapping geographical areas, and on the other hand four haplogroups, positioned according to a geographical pattern. The most probable scenario involves a homing behavior of individuals from cluster 1 (homing at the scale of large watersheds), which prefer or tend to return to the Madera basin, with the three populations coexisting within the upper Madera because they reproduce at different moments (phenology) or different places (spatial segregation). Finally, the results are discussed in the light of previous results in the Amazon basin and the threats to the species in the Madera basin (p.e. fragmentation by dams, overfishing, climate variability, among other)
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Bido, Adriane Federici. "Indicadores de estresse em curimba (Prochilodus lineatus) (Valenciennes, 1836) em escada para peixes, no Alto Rio Paraná, Brasil." Universidade Estadual do Oeste do Parana, 2016. http://tede.unioeste.br:8080/tede/handle/tede/712.
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Stress is an adaptive component that allows the fish to deal with various stressful events that occur during the life cycle of fish, such as the reproductive migration that demands physical efforts. The aim was to assess whether the steps for implementation to fish in the reservoir dam is promotes stress in curimba (Prochilodus lineatus). Adult fish species were sampled in March 2015 at three sites in the Hydroelectric Powerplant of Porto Primavera, Upper Paraná River, Brazil: downstream, the fish ladder and upstream of the dam, totaling 48 individual. Variations in body weight, standard length, and determination of plasma concentrations of cortisol, glucose, lactate, choloride and hematocrit they were analyzed in relation to gender and local sampled. The body weight and standard length presented comparable values for each location between genders, but the averages of females were significantly higher. Significant increase in plasma levels of glucose and lactate were observed but without significant changes in cortisol, chloride levels, as well as in hematocrit. The intense exercise of the fish by the transposition of fish ladder represented moderate stressor, without causing harmful effects to these animals, since the recovery of fish at the upstream from the dam. These results are deepening about the physiology used as a tool for conservation by providing knowledge and subsidies for the conservation and management of migratory species.
Resumo O estresse é um componente adaptativo que permite ao peixe lidar com eventos estressores que ocorrem durante o ciclo de vida dos peixes, como, por exemplo, a migração reprodutiva que exige esforço fisiológico dos animais. O objetivo do trabalho foi avaliar, por meio de indicadores fisiológicos, se a transposição de escada para peixes em barragem de reservatório representa um evento estressor para o curimba (Prochilodus lineatus). Peixes adultos da espécie foram amostrados em março de 2015 em três locais na Usina Hidrelétrica de Porto Primavera, Alto Rio Paraná, Brasil: a jusante, na escada para peixes e a montante da barragem, totalizando 48 indivíduos. Variações do peso corporal, comprimento padrão e das concentrações plasmáticas de cortisol, glicose, lactato, cloreto e hematócrito foram analisadas em relação ao gênero e local amostrado. O peso corporal e o comprimento padrão apresentou valores similares em todos os locais de coleta, nos dois gêneros, porém as fêmeas foram significativamente maiores a montante. Aumento significativo nos níveis plasmáticos de glicose e lactato foram observados, mas sem alterações significativas das concentrações circulantes de cortisol, cloreto e do hematócrito. O exercício intenso dos peixes pela transposição da escada para peixes representou uma condição moderadamente estressante, sem causar prejuízo biológico, visto a recuperação observada a montante. Estes resultados são aprofundamentos sob a fisiologia utilizada como ferramenta para conservação fornecendo conhecimento e subsídios para a conservação e manejo de espécies migratórias.
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Guiot, de la Rochère Léo. "Cours d'eau régulés et provision de services écosystémiques : contrôle d'ouvrages pour la migrations d'espèces piscicoles." Thesis, Toulouse, INPT, 2020. http://www.theses.fr/2020INPT0085.
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Mon travail de thèse s’intéresse au rétablissement de la continuité de la migration piscicole dans des réseaux d'irrigations, et plus particulièrement le cas des marais littoraux fortement régulés. Nous traitons le cas particulier du marais de Charras (estuaire de La Charente), et comme espèce cible nous nous intéressons à l’Anguille (a son stade de développement communément appelé civelle). Il s’agit d’un marais où l’écoulement est fortement régulé par des ouvrages de régulations: portes à flots, clapets, vannes. Or ces ouvrages sont des obstacles à la libre circulation des civelles. Dans un premier temps, nous nous sommes intéressés à la description du fonctionnement des ouvrages spécifiques à la gestion de l’eau dans les réseaux côtiers (portes à flots et clapet), et des solutions hydromécaniques permettant leurs franchissements (cale, raidisseur, et flotteur). Nous avons développé un modèle de fonctionnement de ces ouvrages permettant de dimensionner et comparer les solutions hydromécaniques existantes. Puis dans un second temps, nous avons étudié le comportement de la civelle au niveau des vannes. Nous avons vérifié, in-situ, la limite de vitesse de nage des civelles établie en laboratoire. Et nous avons mis en évidence que des modifications d’écoulement locales à l’aide de rugosités ne permettaient pas d’améliorer le franchissement des civelles. La troisièmes partie est consacrée à l’amélioration du passage des civelles aux niveaux d'ouvrage d’étagement (vannes et seuils) par modification de leurs gestions. Un modèle hydraulique basé sur les équations de Saint-Venant 1D du marais de Charras a été réalisé. Il permet d’évaluer l’impact des modifications de gestions des ouvrages de contrôle (porte à flot, clapet, vanne,…) sur les paramètres hydrauliques contraints par les besoins d’exploitation (ici les hauteurs d’eau, et les débit) et les grandeurs physiques de l’écoulement contrôlant le passage des civelles au niveau des ouvrages d’étagement (ici la vitesse de l’écoulement). Une quatrième partie présente plusieurs campagnes de suivi de conductimétrie dans le marais de Charras. Ils ont été mis en place pour évaluer l’impact du rétablissement de la continuité de la migration piscicole sur un réseaux hydrographique d’eau douce. Ils mettent en évidence que les solutions de franchissement piscicole permettent des intrusions salines qui complexifient l’écoulement: il est alors fortement stratifiéThis PhD thesis investigates the fish migration continuity restoration in irrigation network, more specifically the highly regulated coastal marshes. We consider the study case of the Charras marsh (Charent estuary), and we focus on the eel migration (in particular on its lifestage part called glass eel). It is a highly regulated marsh where the flow regulate whiwh hydraulics structures: tide gates, flap gates, sluices gates. These structures are obstacles to glass eel migration. We start by studing specific structures for water management in coastal networks (flood gates and flap gates), and hydromechanical solutions for fish passage (blocks, stiffeners and floats). We propose an operating model for these specific structures that takes these hydromechanical solutions for fish passage into account. The model makes it possible to evaluate the impact of these solutions on the passabilities for fish, and on their performance in terms of hydraulic regulation. Then we studied the glass eel behaviour in front of a sluice gate. We verified, in situ, the swimming speed limit of the glass eel established by laboratory studies. And we showed that local flow modifications using roughnesses did not improve glass eel passage at sluice gate. The third part is devoted to the improvement of the glass eel passage at sluice gates (or weirs) by modifying their management rules. To evaluate the impact of these adaptations, a model of the marsh was built, based on the one-dimensional Saint-Venant equations and appropriate gate equations. It allows to evaluate the impact of the modifications of the control structures management (gate, flap gate, sluice gate,...) on: the key hydraulic parameters for the exploitation needs (water levels and flow rates), and the physical quantities of the flow controlling the passage of the elvers at the level of the structures (Flow velocities at the hydraulic structures). A fourth part presents several conductivity monitoring campaigns in the Charras marsh. They were made to assess the impact of restoring the fish migration continuity at coastal water control structures, on a freshwater hydrographic network. They show that the fish passage solutions allow saline intrusions that modify the flow: it becomes highly stratified
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Gutfreund, Carola. "Efetividade da escada para peixes de uma barragem no rio Paraná para duas espécies migradoras neotropicais." Universidade Estadual do Oeste do Paraná, 2017. http://tede.unioeste.br/handle/tede/3547.
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Large hydroelectric dams along the Paraná River have caused severe impacts on fish communities as they represent obstacles to long-range migratory species that need to migrate to complete their life cycle. Dams can bring numerous problems through the interception of migratory routes and reduction of spawning areas. The most common measures used to mitigate the effect of these physical obstacles is the implementation of fish ladders. It is not only important to implement these structures, but also to monitor them. This study was performed at the Engenheiro Sergio Motta Hydroelectric Power plant in the Upper Paraná River during December/2012 and March/2016. The aim of it was to evaluate the effectiveness of this structure in relation to the attractiveness rate and passage efficiency of to two Neotropical fish species in the fish ladder. In total, 563 fish of genus Leporinus (447 Leporinus obtusidens and 116 Leoporinus piavussu) were tagged and released with the implementation of 32-mm programmable transponders (PIT-tags). Radio Frequency Identification (RFID) was used to monitor the system. The attractiveness of the ladder was 8.7%. The minimum time to find it was 1.49 days for the fish released upstream and the maximum time was 449.86 days for the individuals released downstream. The release site had a significant influence on the entry rate of fish released on the other side of the river. No detection was observed for fish released downstream and upstream on the right bank of the river. Only the fish released on the same site where the fish ladder is located were detected, suggesting low attractiveness of the ladder in relation to the studied species. In the course of this study it was verified that for the two species studied it would be extremely important to increase the attractiveness at the entrance of the ladder, as well as to build a second ladder for fish on the right side of the river.
As grandes hidrelétricas ao longo do Rio Paraná têm causado impactos severos nas comunidades de peixes, pois representam obstáculos para as espécies migradoras de longa distância, que precisam migrar para completar seu ciclo de vida. As barragens podem trazer inúmeros problemas por meio da intercepção das rotas migratórias e redução das áreas de desova. As medidas mais comuns utilizadas para mitigar o efeito desses obstáculos físicos é a implementação de escadas para peixes. Não é somente importante a implementação dessas estruturas, como também o monitoramento. Esse estudo realizado na escada para peixes da Usina Hidrelétrica Engenheiro Sérgio Motta no alto Rio Paraná no período de dezembro/2012 a março/2016 teve como objetivo avaliar a efetividade dessa estrutura em relação a taxa de atratividade e eficiência de passagem para duas espécies de peixes migradores neotropicais. No total, foram marcados e liberados 563 peixes do gênero Leporinus (447 Leporinus obtusidens e 116 Leoporinus piavussu) com a implantação de transponders com códigos programáveis (PIT-tags) de 32 mm. Foi utilizado o sistema de rádio frequência (RFID Radio Frequency Identification) para o monitoramento do sistema. A atratividade da escada foi de 8,7%. O tempo mínimo para encontrar a escada correspondeu a 1,49 dias para os peixes liberados a montante e o tempo máximo foi de 449,86 dias para os indivíduos liberados a jusante. O local de liberação influenciou significativamente a taxa de entrada dos peixes liberados na margem oposta do rio, sendo que nenhuma detecção foi observada para peixes liberados na margem direita, tanto a jusante como a montante. Foram detectados apenas os peixes liberados na mesma margem onde a escada para peixes está localizada, sugerindo baixa atratividade da escada para as espécies analisadas. No decorrer deste estudo verificou-se que para as duas espécies estudadas seria extremamente importante aumentar a atratividade na entrada da escada, como também a construção de uma segunda escada para peixes no lado direito do rio.
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Holliland, Per B. "Trophic interactions and behaviour : Studies relevant to a Baltic Sea biomanipulation." Doctoral thesis, Stockholms universitet, Systemekologiska institutionen, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-79075.
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The main theme of this thesis is the interactions of animals with the environment and each other. The thesis was written within the framework of a biomanipulation project “Pikeperch in Himmerfjärden”. With the aim to investigate possible trophic pit-falls, give the manipulation the best possible start, and find ways to monitor the progression of the manipulation. In Paper I the diet of the invader cladoceran Cercopagis pengoi is analysed with stable isotopes; conducted prior to stocking. C.pengoi has a preference for large copepods, indicating possible competition with fish. Paper II investigates the behavioural differences between pikeperch fingerlings reared in different environments (pond vs. tank). Results suggest that fish reared in semi-natural ponds are more likely to survive directly after stocking. In Paper III and IV, the diel vertical migrations (DVM) of copepods are in focus. In Paper III the migrations of two copepod species: Acartia spp. and Eurytemora affinis are studied over season and life stage. The amplitude of migration was found to increase with ontogeny for both species, indicating evasion of visual predators. Paper IV examines the varying migratory patterns of adult female E. affinis finding that these animals migrate more actively when feeding conditions deteriorate and growth decreases. The overall conclusions of the thesis are that behavioural, not only direct trophic interactions are key when studying ecosystems.At the time of the doctoraldefense, the following papers were unpublished and had a status asfollows: Paper2: In press. Paper 4: Manuscript.
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Melo, Bruno Francelino de [UNESP]. "Genética de populações de Prochilodus argenteus e P. costatus do médio São Francisco." Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/92543.
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O Rio São Francisco forma uma das maiores bacias hidrográficas sulamericanas e vem sofrendo grandes impactos causados por ações antrópicas. A bacia conta com uma rica fauna de peixes, muitos de elevada importância para a pesca comercial e de subsistência. O estado de Minas Gerais apresenta uma importante indústria pesqueira e a região de Três Marias representa a zona mais produtiva na bacia do São Francisco. Nesta região, duas espécies de peixes são encontradas abundantemente: Prochilodus argenteus (curimatã-pacu), responsável por até 50% do pescado, sendo a espécie de maior porte da família Prochilodontidae com alguns indivíduos alcançando 15 kg, e Prochilodus costatus (curimatã-pioa) que possui um importante papel ecológico e para a pesca de subsistência. Estudos prévios sugerem a existência de diferentes populações de P. argenteus na região de Três Marias e de apenas uma população de P. costatus na mesma área. No entanto, os níveis de estruturação e os padrões de migração das espécies não foram testados utilizando indivíduos pertencentes aos tributários de todo o médio São Francisco. No presente estudo, duas hipóteses foram testadas: (i) os peixes que nascem nas lagoas marginais dos tributários vivem, preferencialmente nesses próprios tributários, não migrando para o leito do São Francisco; (ii) os peixes que nascem nas lagoas dos tributários migram preferencialmente para o leito do São Francisco no período de alimentação, retornando aleatoriamente ou não para os tributários durante o período de reprodução. Nove amostragens de P. argenteus com um total de 273 espécimes e cinco de P. costatus com 156 espécimes foram coletadas em todo o médio São Francisco em dois períodos, chuvoso e seco. Utilizamos seis loci microssatélites altamente polimórficos e os resultados indicaram...
The São Francisco is one of the largest South America river basin and has suffered large impacts caused by human actions. The basin has a rich fish fauna, many of great importance for commercial fishing and for subsistence. The Minas Gerais State has a strong fishery activity and the Três Marias region is the most productive fishing region in the São Francisco basin. In this region, two fish species are abundantly found: Prochilodus argenteus (curimatã-pacu), representing almost 50% of the total catch, being the largest member of the Prochilodontidae family sometimes reaching a body weight of 15 kg and P. costatus (curimatã-pioa) that has an important ecological role and for subsistence fishing. Previous studies suggest the existence of distinct populations of P. argenteus and only one population of P. costatus in the Três Marias region. However, the structuring levels and migration patterns were not tested using individuals from tributaries of the middle São Francisco. Here we tested two hypotheses: (i) fishes recruited on marginal lagoons from tributaries live preferably in these tributaries; (ii) fishes recruited on marginal lagoons from tributaries preferentially migrate downstream to the main stream of the São Francisco River in the feeding season, returning upstream randomly or not to the tributaries for reproduction. Nine populations of P. argenteus with 273 specimens and five populations of P. costatus with 156 specimens were collected throughout middle São Francisco in the rainy and dry seasons. We used six highly polymorphic microsatellite loci and the results indicated high levels of variability within populations for both species. Additionally, low values of population differentiation were detected in P. argenteus (FST = 0,008, P < 0,008) and P. costatus (FST = 0,031, P < 0,008) with high values... (Complete abstract click electronic access below)
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Martins, Sidney Lazaro. "Sistemas para a transposição de peixes neotropicais potamódromos." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/3/3147/tde-13092005-084816/.
Full textAbstract:
Os Sistemas para a Transposição de Peixes Neotropicais são, ainda, temas multidisciplinares polêmicos envolvendo cultura ambiental, engenharia, biologia, ecologia, política e economia. Nesse universo de interesses, o econômico diverge do ambiental, principalmente no escopo dos investimentos corporativos em energia hídrica, nos quais a busca de lucros suplanta o compromisso ambiental, deixando o ônus à sociedade e irrelevando o bem renovável dos peixes nos ecossistemas aquáticos. Há um grande interesse corporativo nacional para mistificar e irrelevar as estruturas para passagens de peixes em barramentos de modo à desjustificá-las como alternativa de mitigação de impactos e assim não expandi-las, tornando-as não obrigatórias principalmente em empreendimentos existentes, em que pese às questões ictiológicas abertas e não esclarecidas que deveriam estar em grau de consistência e confiança mais desenvolvidas. Os Estudos de Impactos Ambientais e os relicenciamentos dos barramentos são os instrumentos para disciplinar os STPs, mas deixam a desejar quando os empreendedores ou investidores são também os agentes que financiam os estudos. As agências licenciadoras contam com uns corpos técnicos inexperientes e susceptíveis a informações parciais e com forte empenho político e econômico. A concepção, projeto, manuseio de vazões, níveis, velocidades, potência do escoamento são de natureza hidráulica para as quais os engenheiros, atendendo as premissas biológicas dos peixes, são os agentes indicados para o tratamento dos sistemas para a transposição de peixes em barragens. Neste trabalho há as propostas para STPs nacionais baseadas em de estudos de similitude tridimensional; a apresentação de recomendações e critérios baseados na experiência nacional além da proposta experimental de criadouros artificiais em reservatórios e afluentes simulando-se os baixios e lagoas marginais. Para que as informações contidas neste trabalho não sejam reproduzidas erroneamente: as dimensões do STP devem ser concebidas em função das espécies a serem transportadas, que variam segundo as variáveis ambientais locais. O projeto de um STP não pode ser padronizado, pois implicará em erros. Padronizar um STP é reduzir a técnica e a ciência a um padrão primário, tipo Manual de Bolso, o que não atenderia aos peixes, fadando a concepção ao insucesso.The theme Systems for Neo-tropical Fishes Transposition is a multidisciplinary subject: it encompasses the fields of engineering, biology, ecology, politics, economy and environmental culture. It is also a polemic subject: in a broad range of interests, most of the time the economical overtake the environmental ones. This is especially true when corporative investments in hydroelectric energy are under consideration, where seek for profits supersedes the environmental commitments, leaving to the community the liability of endangering fish species renewal in aquatic ecosystems. In fact, there is a strong corporative interest, in the national context, to obstacle fish passage devices, not only for new dam structures, but also for the existing ones. Among the local entrepreneurs there is a tendency to mystify and underestimate fish passage structures, as a way to disqualify them as effective mitigative measures. The development of a fish passages culture in the country becomes even more difficult. Additionally, there are several non-clarified questions related to neo-tropical fish species; those issues should already be in a more developed consistency and soundness stage. Environmental Impact Assessments and existing dams Re-licensing Processes should play a disciplinary role for fish passage structures, but they usually fail when the investors and/or entrepreneurs are the ones who financially support those studies. Even worse, licensing agencies technical staffs frequently lack on reliable information and let themselves be guided by political and economical interests. The treatment of discharges, water levels, velocities, energy of flow, dimensions and layout or, in a broader sense, the conception and design of fish passage structures, should only be carried out by specialist engineers, with the invaluable supervision of biologists. The objective of this Thesis is the proposition of fish passage structures adapted to the conditions of Brazilian rivers and following the results of studies with reduced scale tri-dimensional models. Also some recommendations and criteria are presented, supported by the feedback from nationwide experience. Finally, a proposition is presented for the experimental implementation of artificial breeding farms along reservoirs and tributaries, where the conditions of swamps and peripheral ponds could be reproduced. The dimensions of the STP must be function of the species to be transponding, of this form its conception cannot be standardized, therefore it will imply in errors. To standardize a STP is to reduce the technique and science to a secundarista standard, Manual of Pocket, what it would not take care of to the fish, predestinateing the conception to failure.
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Buck, Sine. "Determining the best location for a nature-like fishway in Gavle River, Sweden." Thesis, Högskolan i Gävle, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-15725.
Full textAbstract:
The construction of dams and hydro-power stations are some of the most common anthropogenic changes of watercourses and rivers. While being important to humans and society by providing electricity, these obstructions of watercourses can have severe consequences for the aquatic ecosystems. One consequence is that dams often hinder the important movement of migrating fish species between habitats. This can lead to decline and even extinction of important fish populations. To prevent these negative effects, a number of different fish passage systems, including nature-like fishways, have been developed. Nature-like fishways mimic natural streams in order to function as a natural corridor for a wide range of species. Planning and construction of a nature-like fishway is a complex task that often involves many different interests. In the present study a combination of multi-criteria decision analysis and least-cost path analysis is used for determining the best location for a nature-like fishway past Strömdalen dam in Gavleån, Sweden. An anisotropic least-cost path algorithm is applied on a friction-layer and a digital elevation model, and the least-cost path for a nature-like fishway is determined. The results show that the method is useful in areas of varying topography and steep slopes. However, because low slope is a very important factor when constructing a nature-like fishway, slope becomes the dominating factor in this analysis at the expense of e.g. distance to roads. Combining the methods with results from biological studies of fish behavior and detailed hydrological modelling would provide a very strong tool for the planning of nature-like fishways.
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Elder, Timothy Sean. "Ecology and Population Dynamics of Salmonids in the Columbia River: Response of Fishes to Anthropogenic Change in a Large Riverscape." PDXScholar, 2018. https://pdxscholar.library.pdx.edu/open_access_etds/4635.
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Freshwater ecosystems and the species that reside therein are disproportionately imperiled compared to terrestrial systems. Over the past 150 years, the Columbia River basin in the western United States has gone from one of the most productive and abundant salmon watersheds in the world, to having just a small fraction of its former salmon abundance. The cause of declines in salmon productivity and abundance are related to overlapping and confounding stressors including changes in large-scale climatic patterns and anthropogenic alterations within and adjacent to the Columbia River. Four main anthropogenic stressors have been identified as the leading causes of salmonid declines: commercial harvest of adult salmon, hydroelectric power generation and associated reservoirs, habitat loss due to impassible dams and restricted access to historical habitat, and hatchery production.
My dissertation broadly examined how salmon ecology and population dynamics have been influenced by anthropogenic alterations occurring within the Columbia River basin. This dissertation addresses three main questions: Do the hydroelectric dams on the Lower Columbia River represent a pulse- or press-type ecological disturbance to migrating Chinook salmon (Oncorhynchus tshawytscha) and steelhead (O. mykiss) and what are the biotic and abiotic factors that most influence the survival of fish passing multiple dams? How do wild and hatchery fish differ in regards to the precocious life-history strategy, and which variables influence this strategy across environments (freshwater to marine) and life stages (egg to adult)? What are the morphological differences between wild and hatchery salmonids and how much of that variation is attributable to rearing-environment?
I found that high outflow volumes led to involuntary spill in 2011 and created an environment of supersaturated dissolved gas concentrations. In this environment, migrating smolt survival was strongly influenced by barometric pressure, fish velocity and water temperature. The effect of these variables on survival was compounded by multiple dam passages compared to fish passing a single dam. Despite spatial isolation between dams in the Lower Columbia River hydrosystem, migrating smolt appear to experience cumulative effects akin to an ecological press disturbance. In general, Chinook salmon and steelhead respond similarly in terms of survival rates and responses to altered environmental conditions. Management actions that limit dissolved gas concentrations in years of high flow will benefit migrating salmonids during this life stage.
Both biotic and environmental factors affect precociousness in hatchery and wild Chinook salmon, across freshwater and marine environments. Wild fish are influenced by density-dependent processes in freshwater, as well as marine conditions that promote growth. Wild Chinook have the highest probability of precocious maturation when large smolt (>150 mm) experience productive marine environments within the first several months of ocean residence. Precocious hatchery fish are broadly influenced by conditions experienced during freshwater residency, outmigration, and in marine habitats. There was no interaction between the size of hatchery fish and environmental variables, suggesting that these fish attained the size required to mature precociously prior to migration. These results indicate that hatchery Chinook salmon do not respond to the same environmental cues that determine life history transitions as wild Chinook salmon, likely as a result of different physiological conditions and environmental exposures during early life stages. There are ecological and economic consequences to the precocious life history strategy including reduced marine-derived nutrients entering freshwater ecosystems and a loss of investment for fish intended for the adult fishery.
There are significant differences in body shape between wild and hatchery origin Chinook salmon and steelhead that can be partially explained by rearing environment and variables influenced by smoltification. Hatchery fish of both species are significantly larger (i.e. centroid size, length, weight) than wild fish but have comparable or lower condition factor. In general, hatchery fish have smaller heads and longer, thinner tails (i.e. fusiform) compared to wild fish. Allometric trajectories (i.e. shape change with size) indicate that the shape of wild and hatchery fish are significantly different at small and large sizes. Wild and hatchery Chinook salmon became more morphologically different as size increased, while steelhead became more similar. The overall amount of shape variation was not significantly different between wild and hatchery Chinook salmon. This finding suggests that regardless of significant differences in the way shapes vary, hatchery Chinook have not lost overall shape variation. Total amount of shape variation was significantly greater in wild compared to hatchery steelhead, indicating that hatcheries may have a homogenizing effect on steelhead shape. I recommend a coordinated effort between federal, state and tribal hatcheries to incorporate elements of the natural rearing environment into conventional hatcheries. These elements include in-water structure that promotes the burst swimming mode, increased water velocities to increase dorsal-ventral distance, under-water feeding apparatus that reduce surface feeding behavior, overhead cover and mimicked predators to teach escape behavior.
Major advancements have been made in identifying and ameliorating negative effects of anthropogenic alterations within the Columbia Basin, however, many wild populations continue to decline. My research suggests that the physical (i.e. weirs and bypass structures) and operational alterations (i.e. voluntary spill) to the lower Columbia hydrosystem have substantially improved conditions for migrating smolt compared to past years, but involuntary spill during years of high flow continue to create deleterious conditions for migrating smolt. Riverscape-scale management strategies that recognize biotic and abiotic connectivity between dams (i.e. press disturbance) will benefit migrating smolt. My research indicates that hatchery fish are not currently equal or adequate replacements for wild fish. Hatcheries vary greatly in their stated goals and desired outcomes and several coordinated changes to general hatchery practices may help produce fish that are more similar to wild fish in morphology and life histories: 1) Change the goals of production away from producing as many, large individuals as possible, to producing fish that resemble the target wild populations they are intended to support; 2) Alter the hatchery environment to reflect the rearing environments in which salmon evolved and into which they will be released; and 3) Reduce the annual number of hatchery fish released into the Columbia Basin for the sole purpose of harvest. Recovering and rehabilitating critical and diverse habitats utilized by salmonids at each life stage (spawning, rearing, migration, estuary and marine) remains crucial for wild population success into the future.
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Pereira, Esmeralda Cristina Duarte. "Avaliação da eficiência da passagem para peixes do Açude-Ponte de Coimbra para espécies migradoras." Master's thesis, Universidade de Évora, 2014. http://hdl.handle.net/10174/14234.
Full textAbstract:
O presente trabalho enquadra-se no projecto de monitorização da passagem para peixes (PPP) do Açude-Ponte de Coimbra. Desde 2012 e até agosto de 2014, várias técnicas de biotelemetria (radio, EMG, PIT) foram empregues com o objectivo de avaliar a eficiência de passagem para montante deste dispositivo para lampreia-marinha (Petromyzon marinus), barbo do Norte (Luciobarbus bocagei), boga-comum (Pseudochondrostoma polylepis), e muge (Liza ramada), bem como identificar o comportamento da lampreia-marinha a jusante e no interior da PPP.
Enquanto para a lampreia-marinha e barbo do Norte a eficiência de passagem foi de 30%, a boga-comum e muge apresentaram eficiências baixas (6% e 4%, respetivamente), sendo necessária uma reavaliação. O tempo e permanência da lampreia-marinha a jusante do açude é elevado (tempo mediano = 11-14 dias) mas a transposição da PPP decorre em 3 horas, sendo o limite crítico de natação ultrapassado em menos de 1% do tempo total.
Estes resultados têm implicações no dimensionamento de novas PPP, na gestão de caudais que maximizam a respetiva eficiência para a lampreia-marinha e constituem uma base de referência a futuras monitorizações; Abstract:
“Efficiency of the Coimbra Açude-Ponte dam fishway for migratory species”
The present study is part of the Coimbra Açude-Ponte dam fishway (PPP) monitoring program in Coimbra, Portugal. From 2012 to august 2014, several bio-telemetry techniques (radio, EMG, PIT-tag) were employed with the aim of assessing this structure’s upstream passage efficiency for sea lamprey (Petromyzon marinus), Iberian barbel (Luciobarbus bocagei), Iberian nase (Pseudochondrostoma polylepis), and thinlip grey mullet (Liza ramada), as well as identifying sea lamprey behavior downstream and within the PPP.
While sea lamprey and Iberian barbel passage efficiency was 30%, Iberian nase and thinlip grey mullet showed low efficiencies (6% and 4% respectively) with a new assessment being necessary. Sea lamprey spent a great amount of time downstream the Açude-Ponte (median time= 11-14 days), however once in the PPP individuals took only 3 hours to successfully negotiate this structure, and the critical swimming speed was exceeded less than 1% of the total time.
These results have implications in the development of new fishways, in flow management actions that maximize efficiency for sea lamprey, and can be used as a reference for future assessments.
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Turenne, Eric D. "Lipid Mobilization In Exercising Salmonids." Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/37075.
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Animals rely on lipids as a major fuel for endurance exercise because they pack more joules per gram than any other fuel. However, in contrast to mammals, information on how the mobilization of lipids from endogenous stores is managed to meet the needs of energy metabolism in swimming fish is sparse. Information on in vivo rates of lipid mobilization in swimming fish has been limited to relatively low exercise intensities and has only been investigated in a single species. Therefore, the goal of my thesis was to address this paucity of information by quantifying lipolytic rate in rainbow trout during graded exercise and fatty acid mobilization in Atlantic salmon during prolonged endurance exercise.
In the first part of my work, I hypothesized that like mammals, rainbow trout stimulate lipolysis above resting levels to a peak with increasing work intensity, but subsequently lower its rate at high intensities when ATP production from carbohydrates becomes dominant. To test this hypothesis, I measured the rate of appearance of glycerol (Ra glycerol) in the blood (resulting from the breakdown of triacylglycerol (TAG)) of trout at rest (control) and during graded exercise from rest to Ucrit. Results showed that Ra glycerol in trout averaged 1.24 ± 0.10 µmol kg -1 min-1 and that this rate was unaffected by exercise of any intensity. These experiments revealed that rainbow trout do not modulate lipolysis during exercise. Furthermore, I calculated that baseline lipolytic rate was much higher in trout than in mammals and that this rate is in constant excess of the requirements of energy metabolism.
My second investigation focused on measuring fatty acid mobilization in Atlantic salmon. To date, the majority of studies on energy metabolism in salmonids have used rainbow trout as the ubiquitous model for salmonids. I postulated that domesticated rainbow trout may be far less impressive athletes than their wild anadromous form and other salmonids. In this regard, I proposed that studying energy metabolism in Atlantic salmon (even those from aquaculture) may help to deepen our understanding of the physiology of true long-distance migrant fish. To study the effects of prolonged endurance exercise on the mobilization of fatty acids from endogenous stores in these fish, I monitored the rate of appearance of fatty acids (Ra NEFA calculated from Ra Palmitate) in the blood during 72 hours of sustained swimming. I found that contrary to what has been previously described in rainbow trout, Ra Palmitate (and by proxy, Ra NEFA) is reduced by approximately 64% (from 0.75 ± 0.12 µmol kg-1min-1 to 0.27 ± 0.06 µmol kg-1min-1 and from 19.3 ± 7.8 µmol kg-1min-1 to 6.9 ± 2.0 µmol kg-1min-1 for Ra Palmitate and Ra NEFA, respectively) during prolonged endurance exercise in Atlantic salmon. However, like in trout, even this reduced rate of fatty acid mobilization exceeds the requirements of energy metabolism at rest and during swimming. While further experiments will be necessary, I speculated that this reduction in Ra NEFA may be caused by a partial inhibition of lipolysis to reduce the energetic cost of TAG:FA cycling and optimize fuel budgets during prolonged endurance exercise.
This thesis provides the first in vivo measurements of lipolysis during graded exercise in salmonids and the first in vivo measurements of fatty acid mobilization in Atlantic salmon. From the results mentioned above, I concluded that salmonids mobilize lipids in constant excess of the requirements for energy metabolism, possibly to allow for rapid reorganization of membrane phospholipids in response to changing environmental conditions. However, more anadromous and migratory phenotypes may rely on a tighter control of lipolysis to minimize the costs of substrate cycling and conserve energy on limited fuel stores.
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Wasserman, Ryan. "The importance of estuarine head waters for fishes in selected Eastern Cape systems, with particular emphasis on the influence of freshwater inflow, migration barriers and non-native predators on the juvenile and small fish component." Thesis, Nelson Mandela Metropolitan University, 2010. http://hdl.handle.net/10948/1457.
Full textAbstract:
The utilisation of estuary headwater environments by young estuary- and marine-spawned fish species was investigated together with the effects of riverflow alteration, in-stream barrier effects and non-native ichthyofauna on the nursery function of these habitats. The distribution and abundance of young estuary- and marine-spawned fish were sampled using seine and fyke nets in the headwater environments of four permanently open Eastern Cape systems, namely the Great Fish, Kowie, Kariega and Sundays Estuaries. Within the suite of study systems, the first of two case studies focussed on barrier effects of in-stream structures on fish migration. This was undertaken in the Sundays River. In the second case study, predation and competition dynamics of the non-native piscivorous Micropterus salmoides on estuary-dependent fish was investigated in the estuary headwater regions of the Kowie River system. In all four estuaries, young estuary-spawned fish species dominated the ichthyofaunal community followed by marine-spawned species, despite varied freshwater inflow resulting in headwaters varying in salinity from fresh to hypersaline. Fish community structure however, differed largely between estuaries, with both freshwater abstraction and unnatural elevation of freshwater into estuaries, as a result of inter-basin transfers, affecting these communities. In-stream structures were found to effect upstream movement of fish in two ways, dependent on the type of barrier. Partial (size-dependent) and complete (species-dependent) restriction to upstream migration of fish by causeway-type instream structures were observed. Weir-type in-stream structures acted as a complete barrier to most species, regardless of fish size. Predation of estuary- and marine-spawned fish species by large sized M. salmoides was recorded, although these fish did not contribute significantly to their diet during this study. However, the main dietary components found in smaller sized M. salmoides stomachs overlap with those of juvenile estuary- and marinespawned fish species, suggesting feeding competition between the juveniles of indigenous and non-native fish species.
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Samia, Yasmine. "Persistence of River Populations." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/34495.
Full textAbstract:
Streams and rivers are examples of vital ecosystems that frequently undergo various environmental and anthropogenic stresses. A core question in population ecology is whether a given population will persist under changing ecological conditions. This thesis consists of three papers and is devoted to the mathematical analysis of responses of river-dwelling species to population persistence threats. The first paper presents a stochastic approach to the 'drift paradox' problem, where the classical reaction-advection-diffusion model is replaced by a birth-death-emigration process. We explore the effects of temporally varying flow on the
persistence probability and highlight the importance of the benthic stage for the persistence of stream organisms. The second paper addresses the problem of river network fragmentation through disconnecting structures such as dams. We construct a population matrix model that incorporates the spatial structure of the studied river network and compare structural connectivity to an indicator of population persistence. The third paper adapts the same basic matrix model to examine fish response to disturbances travelling downstream from upstream sites. The study of these three aspects of persistence challenges for river populations
contributes to the cumulative effects assessment on river networks.
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Gisen, David Christoph [Verfasser], Andreas [Akademischer Betreuer] Malcherek, Andreas [Gutachter] Malcherek, Volker [Gutachter] Grimm, and Christoph [Gutachter] Heinzelmann. "Modeling upstream fish migration in small-scale using the Eulerian-Lagrangian-agent method (ELAM) / David Christoph Gisen ; Gutachter: Andreas Malcherek, Volker Grimm, Christoph Heinzelmann ; Akademischer Betreuer: Andreas Malcherek ; Universität der Bundeswehr München, Fakultät für Bauingenieurwesen und Umweltwissenschaften." Neubiberg : Universitätsbibliothek der Universität der Bundeswehr München, 2018. http://d-nb.info/1182946011/34.
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Gisen, David Christoph [Verfasser], Andreas Akademischer Betreuer] Malcherek, Andreas [Gutachter] Malcherek, Volker [Gutachter] Grimm, and Christoph [Gutachter] [Heinzelmann. "Modeling upstream fish migration in small-scale using the Eulerian-Lagrangian-agent method (ELAM) / David Christoph Gisen ; Gutachter: Andreas Malcherek, Volker Grimm, Christoph Heinzelmann ; Akademischer Betreuer: Andreas Malcherek ; Universität der Bundeswehr München, Fakultät für Bauingenieurwesen und Umweltwissenschaften." Neubiberg : Universitätsbibliothek der Universität der Bundeswehr München, 2018. http://d-nb.info/1182946011/34.
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Jágr, Josef. "Revitalizace jezu ve Vranovicích na Svratce rybím přechodem." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2012. http://www.nusl.cz/ntk/nusl-225702.
Full textAbstract:
This present work deals with the design of revitalization measures for the weir in Uherčice (Vranovice) on the river Svratka. The current condition of weir constuction does not allow aquatic animals to migrate, weir constuction is transverse barrier. In this river section are found many fish species like barbel, vimba, nase and chub, for which is migration completely natural part of their behavior. There is concrete weir with a movable flap and on the right bank is located a small hydroelectric power plant. Close to hydroelectric power plant outlet is mouth of Šatava river. Weir revitalization consists of fish pass construction. Proposed fish pass is located on the right bank of the stream. There is a close-to-nature bypass channel that will ensure a continuity of water flow of already mentioned river Svratka between Věstonice lake and Rajhrad weir. Entrance to the fish pass will use a part of Šatava mount, then will continue in the artificial channel to the upstream part of Svratka river. Fish pass exit cannot breake the function of protective anti-flood embankment of Svratka river, hence there will be used block off construction. During condition of flooding will exist the possibility to shut down proposed fish pass.